Articles de revues : « Grapevine wood pathogen »

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Rolshausen, P. E., F. Trouillas et W. D. Gubler. « Identification of Eutypa lata by PCR-RFLP ». Plant Disease 88, n^o 9 (septembre 2004) : 925–29. http://dx.doi.org/10.1094/pdis.2004.88.9.925.

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Eutypa lata is a vascular canker pathogen of woody plants commonly diagnosed by isolating the pathogen from infected tissue. Related fungi from the same family, the Diatrypaceae, also have been found in association with grapevine in Californian vineyards. An in situ polymerase chain reaction (PCR) method has been developed for detection of E. lata in infected wood tissue. However, our results indicate that this method also would amplify other Diatrypaceous fungi, which could potentially lead to an incorrect diagnosis. Therefore, we developed a PCR-restriction fragment length polymorphism (PCR-RFLP) assay. The internal transcribed spacer (ITS)1/5.8S/ITS2 ribosomal DNA region was amplified by PCR using universal primers, and RFLP patterns were determined after digestion with AluI. The restriction profiles obtained served to distinguish E. lata from wood trunk pathogens of grapevine (Phomopsis viticola, Botryodiplodia sp., Phaeoacremonium aleophilum, and Phaeomoniella chlamydospora), Diatrypaceous fungi (Diatrype sp., Diatrypella sp., Eutypella vitis, and Eutypa leptoplaca), and Cryptovalsa sp. found on dead wood of grapevine, and other Eutypa spp. (E.petrakii var. hederae, E. astroidea, E. crustata, and E. lejoplaca), with the exception of E. armeniacae, which we regard as a synonym for E. lata, and E. laevata, which has not been found on grapevine.

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Moyo, Providence, Lizel Mostert, Christoffel F. J. Spies, Ulrike Damm et Francois Halleen. « Diversity of Diatrypaceae Species Associated with Dieback of Grapevines in South Africa, with the Description of Eutypa cremea sp. nov. » Plant Disease 102, n^o 1 (janvier 2018) : 220–30. http://dx.doi.org/10.1094/pdis-05-17-0738-re.

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Recent studies in grape-growing areas including Australia, California, and Spain have revealed an extensive diversity of Diatrypaceae species on grapevines showing dieback symptoms and cankers. However, in South Africa, little is known regarding the diversity of these species in vineyards. The aim of this study was, therefore, to identify and characterize Diatrypaceae species associated with dieback symptoms of grapevine in South Africa. Isolates were collected from dying spurs of grapevines aged 4 to 8 years old, grapevine wood showing wedge-shaped necrosis when cut in cross section as well as from perithecia on dead grapevine wood. The collected isolates were identified based on morphological characters and phylogenetic analyses of the internal transcribed spacer region (ITS) and β-tubulin gene. Seven Diatrypaceae species were identified on grapevine, namely Cryptovalsa ampelina, C. rabenhorstii, Eutypa consobrina, E. lata, E. cremea sp. nov., Eutypella citricola, and E. microtheca. The dying spurs yielded the highest diversity of species when compared with the wedge-shaped necrosis and/or perithecia. C. ampelina was the dominant species in the dying spurs, followed by E. citricola, whereas E. lata was the dominant species isolated from the wedge-shaped necroses and perithecia. These results confirm E. lata as an important grapevine canker pathogen in South Africa, but the frequent association of C. ampelina with spur dieback suggests that this pathogen plays a more prominent role in dieback than previously assumed. In some cases, more than one species were isolated from a single symptom, which suggests that interactions may be occurring leading to decline of grapevines. C. rabenhorstii, E. consobrina, E. citricola, E. microtheca, and E. cremea are reported for the first time on grapevine in South Africa.

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Úrbez-Torres, J. R., F. Peduto, R. J. Smith et W. D. Gubler. « Phomopsis Dieback : A Grapevine Trunk Disease Caused by Phomopsis viticola in California ». Plant Disease 97, n^o 12 (décembre 2013) : 1571–79. http://dx.doi.org/10.1094/pdis-11-12-1072-re.

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Field surveys recently conducted in California and in other grape-growing regions in the United States showed Phomopsis viticola to be one of the most prevalent fungi isolated from grapevine perennial cankers in declining vines. The current study has not only confirmed the presence of P. viticola from grapevine cankers in California but also has for the first time revealed the occurrence of Diaporthe ambigua, D. eres, and D. neotheicola in symptomatic grapevine wood in California by means of morphological studies and multi-gene sequence analysis. Pathogenicity trials conducted on mature cordons of Vitis vinifera ‘Syrah’ and ‘Red Globe’, as well as on lignified Syrah dormant canes, showed P. viticola isolates from California to be capable of causing perennial cankers. Lengths of vascular discoloration caused by P. viticola were similar to those caused by Eutypa lata and several Botryosphaeriaceae spp., which are well-known grapevine trunk disease pathogens. Additionally, a lack of spring growth was commonly observed in dormant canes inoculated with P. viticola spore suspensions in two pathogenicity trials. As part of this study, V. vinifera ‘Cabernet Sauvignon’ and ‘Zinfandel’ wood was shown to be more susceptible to infection by P. viticola than ‘Barbera’, ‘Chardonnay’, ‘Merlot’, and ‘Thompson Seedless’ wood. After more than 40 years overlooking P. viticola as a grapevine wood pathogen, this study provides strong evidence of the role of P. viticola as a canker-causing organism, and suggests its addition to the fungi involved in the grapevine trunk disease complex. Results from this study suggest D. ambigua and D. neotheicola to be saprophytes or weak pathogens on grapevine wood.

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Yacoub, Amira, Noel Magnin, Jonathan Gerbore, Rana Haidar, Emilie Bruez, Stéphane Compant, Rémy Guyoneaud et Patrice Rey. « The Biocontrol Root-Oomycete, Pythium Oligandrum, Triggers Grapevine Resistance and Shifts in the Transcriptome of the Trunk Pathogenic Fungus, Phaeomoniella Chlamydospora ». International Journal of Molecular Sciences 21, n^o 18 (19 septembre 2020) : 6876. http://dx.doi.org/10.3390/ijms21186876.

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The worldwide increase in grapevine trunk diseases, mainly esca, represents a major threat for vineyard sustainability. Biocontrol of a pioneer fungus of esca, Phaeomoniella chlamydospora, was investigated here by deciphering the tripartite interaction between this trunk-esca pathogen, grapevine and the biocontrol-oomycete, Pythium oligandrum. When P. oligandrum colonizes grapevine roots, it was observed that the wood necroses caused by P. chlamydospora were significantly reduced. Transcriptomic analyses of plant and fungus responses were performed to determine the molecular events occurring, with the aim to relate P.chlamydospora degradation of wood to gene expression modulation. Following P. oligandrum-root colonization, major transcriptomic changes occurred both, in the grapevine-defense system and in the P. chlamydospore-virulence factors. Grapevine-defense was enhanced in response to P. chlamydospora attacks, with P. oligandrum acting as a plant-systemic resistance inducer, promoting jasmonic/ethylene signaling pathways and grapevine priming. P. chlamydospora pathogenicity genes, such as those related to secondary metabolite biosynthesis, carbohydrate-active enzymes and transcription regulators, were also affected in their expression. Shifts in grapevine responses and key-fungal functions were associated with the reduction of P. chlamydospora wood necroses. This study provides evidence of wood fungal pathogen transcriptional changes induced by a root biocontrol agent, P. oligandrum, in which there is no contact between the two microorganisms.

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van Niekerk, J. M., W. Bester, F. Halleen, P. W. Crous et P. H. Fourie. « First Report of Lasiodiplodia crassispora as a Pathogen of Grapevine Trunks in South Africa ». Plant Disease 94, n^o 8 (août 2010) : 1063. http://dx.doi.org/10.1094/pdis-94-8-1063a.

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In 2003 and 2004, a survey of grapevine (Vitis vinifera L.) trunk pathogens was conducted in 30 vineyards in the Western and Northern Cape and Limpopo provinces of South Africa. In each vineyard, 20 visually healthy plants were sampled randomly by removing the distal part of one cordon arm. Isolations were made onto potato dextrose agar (PDA) from the internal wood decay symptoms observed in the cordon samples. Seven Botryosphaeriaceae spp. were identified, including Lasiodiplodia crassispora (1). Other Botryosphaeriaceae spp. are known grapevine trunk pathogens (2). Species identity was confirmed by DNA sequence data of the partial translation factor 1-α gene (1) and sequences deposited in GenBank (GU233658 and GU233659). The L. crassispora isolates (CBS 125626 and 125627) were associated with brown internal necrosis, a known symptom of grapevine Botryosphaeriaceae spp. infection (3), in the cordon arms of Ruby Cabernet grapevines occurring in two vineyards in the Northern Cape Province. L. crassispora was described from cankered wood of Santalum album in Western Australia and endophytically from Eucalyptus urophylla in Venezuela (1). Its grapevine pathogen status was determined using both isolates in a repeated pathogenicity test that included three isolates each of Botryosphaeria dothidea and Neofusicoccum australe as positive controls (2), Trichoderma harzianum as a nonpathogen treatment, and an uncolonized agar plug as a negative control. The Botryosphaeriaceae spp. and T. harzianum were plated on PDA and incubated at 25°C for 7 days. Lignified, 6-month-old shoots of grapevine cv. Chardonnay were excised from grapevines with internodes 4 to 6 used for inoculations. Before wounding, shoots were disinfected by submersion for 1 min in a 1 ml/liter solution of a quaternary ammonium compound (Sporekill; ICA International Chemicals (Pty) Ltd, Stellenbosch, South Africa). Twelve shoots were used for each isolate or control treatment. Wounds were made 2 mm deep on the fifth internode of the shoots with a 5-mm flame-sterilized cork borer (2,3). Wounds were inoculated with a pathogen colonized agar plug (5 mm in diameter) or an uncolonized agar plug and then covered with Parafilm (2,3). Inoculated shoots were incubated in the dark in moist chambers for 14 days at 25°C. After incubation, the bark of the shoots was peeled from the area around the wound and the lengths of any resultant lesions were measured under sterile conditions. The inoculum effect was assessed by analysis of variance and Student's t-test. Results showed that significantly (P < 0.0001) longer lesions were caused by L. crassispora (13.36 mm) compared with N. australe (9.27 mm) and B. dothidea (5.28 mm) and also significantly longer than lesions caused by the nonpathogen and negative controls (3.23 and 2.90 mm, respectively). To determine if lesions were caused by inoculated fungi, isolations were made from the tissue at the edges of the lesions by aseptically removing five 0.5 × 1 mm pieces of wood and placing them on PDA dishes amended with 0.04 g/liter of streptomycin sulfate. Dishes were incubated under normal fluorescent light at 25°C for 14 days before identifying isolated fungi based on morphological and cultural characteristics (1). To our knowledge, this is the first report of L. crassispora as a grapevine pathogen. References: (1) T. I. Burgess et al. Mycologia 98:423, 2006. (2) J. M. van Niekerk et al. Mycologia 96:781, 2004. (4) J. M. van Niekerk et al. Phytopathol. Mediterr. 45:S43, 2006.

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Kaliterna, Joško, Tihomir Miličević et Bogdan Cvjetković. « Grapevine Trunk Diseases Associated with Fungi from the Diaporthaceae Family in Croatian Vineyards / Identifikacija Vrsta Roda Fusarium Izoliranih S Plodova Jabuke Nakon Skladištenja ». Archives of Industrial Hygiene and Toxicology 63, n^o 4 (1 décembre 2012) : 471–79. http://dx.doi.org/10.2478/10004-1254-63-2012-2226.

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AbstractGrapevine trunk diseases (GTD) have a variety of symptoms and causes. The latter include fungal species from the family Diaporthaceae. The aim of our study was to determine Diaporthaceae species present in the woody parts of grapevines sampled from 12 vine-growing coastal and continental areas of Croatia. The fungi were isolated from diseased wood, and cultures analysed for phenotype (morphology and pathogenicity) and DNA sequence (ITS1, 5.8S, ITS2). Most isolates were identified as Phomopsis viticola, followed by Diaporthe neotheicola and Diaporthe eres. This is the first report of Diaporthe eres as a pathogen on grapevine in the world, while for Diaporthe neotheicola this is the first report in Croatia. Pathogenicity trials confirmed Phomopsis viticola as a strong and Diaporthe neotheicola as a weak pathogen. Diaporthe eres turned out to be a moderate pathogen, which implies that the species could have a more important role in the aetiology of GTD.

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Labois, Clément, Elodie Stempien, Justine Schneider, Christine Schaeffer-Reiss, Christophe Bertsch, Mary-Lorène Goddard et Julie Chong. « Comparative Study of Secreted Proteins, Enzymatic Activities of Wood Degradation and Stilbene Metabolization in Grapevine Botryosphaeria Dieback Fungi ». Journal of Fungi 7, n^o 7 (16 juillet 2021) : 568. http://dx.doi.org/10.3390/jof7070568.

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Botryosphaeriaceae fungi are plant pathogens associated with Botryosphaeria dieback. To better understand the virulence factors of these fungi, we investigated the diversity of secreted proteins and extracellular enzyme activities involved in wood degradation and stilbene metabolization in Neofusicoccum parvum and Diplodia seriata, which are two major fungi associated with grapevine B. dieback. Regarding the analysis of proteins secreted by the two fungi, our study revealed that N. parvum, known to be more aggressive than D. seriata, was characterized by a higher quantity and diversity of secreted proteins, especially hydrolases and oxidoreductases that are likely involved in cell wall and lignin degradation. In addition, when fungi were grown with wood powder, the extracellular laccase and Mn peroxidase enzyme activities were significantly higher in D. seriata compared to N.parvum. Importantly, our work also showed that secreted Botryosphaeriaceae proteins produced after grapevine wood addition are able to rapidly metabolize the grapevine stilbenes. Overall, a higher diversity of resveratrol and piceatannol metabolization products was found with enzymes of N. parvum compared to D. seriata. This study emphasizes the diversity of secreted virulence factors found in B. dieback fungi and suggests that some resveratrol oligomers produced in grapevine wood after pathogen attack could be formed via pathogenic fungal oxidases.

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Belair, Marie, Alexia Laura Grau, Julie Chong, Xubin Tian, Jiaxin Luo, Xin Guan et Flora Pensec. « Pathogenicity Factors of Botryosphaeriaceae Associated with Grapevine Trunk Diseases : New Developments on Their Action on Grapevine Defense Responses ». Pathogens 11, n^o 8 (22 août 2022) : 951. http://dx.doi.org/10.3390/pathogens11080951.

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Botryosphaeriaceae are a family of fungi associated with the decay of a large number of woody plants with economic importance and causing particularly great losses in viticulture due to grapevine trunk diseases. In recent years, major advances in the knowledge of the pathogenicity factors of these pathogens have been made possible by the development of next-generation sequencing. This review highlights the knowledge gained on genes encoding small secreted proteins such as effectors, carbohydrate-associated enzymes, transporters and genes associated with secondary metabolism, their representativeness within the Botryosphaeriaceae family and their expression during grapevine infection. These pathogenicity factors are particularly expressed during host–pathogen interactions, facilitating fungal development and nutrition, wood colonization, as well as manipulating defense pathways and inducing impacts at the cellular level and phytotoxicity. This work highlights the need for further research to continue the effort to elucidate the pathogenicity mechanisms of this family of fungi infecting grapevine in order to improve the development of control methods and varietal resistance and to reduce the development and the effects of the disease on grapevine harvest quality and yield.

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GUARNACCIA, Vladimiro, Christian KRAUS, Emmanouil MARKAKIS, Artur ALVES, Josep ARMENGOL, Ales EICHMEIER, Stephane COMPANT et David GRAMAJE. « Fungal trunk diseases of fruit trees in Europe : pathogens, spread and future directions ». Phytopathologia Mediterranea 61, n^o 3 (13 janvier 2023) : 563–99. http://dx.doi.org/10.36253/phyto-14167.

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Production from crops of pome, stone fruit, nut, berry fruit, citrus, grapevine, and olive is increasingly threatened by fungal trunk diseases (FTD). These diseases and the consequent production losses are major problems. Many fungi (including Botryosphaeriaceae, Calosphaeriaceae, Diaporthaceae, Diatrypaceae, Nectriaceae, Phaeomoniellaceae, Pleosporaceae, Togniniaceae, Valsaceae) infect host wood, mainly through wounds and subsequent colonization of woody tissues, causing symptoms such as cankers, gummosis, wood rotting, blight and dieback. Propagative plant material, seedlings and fruit play a significant role in pathogen spread. Several abiotic factors (e.g. shifts in cultural practices and climate change) are involved in the disease development. This paper reviews recent literature on FTD of fruit crops, particularly focusing on the European status of pathogen occurrence. Case studies are described related to diseases of apple, citrus, grapevine, berry, nut and stone fruit, and olive trees. Aspects related to epidemiology and the increase in disease incidence along with the future perspectives on the FTD research are also discussed.

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KASSEMEYER, Hanns-Heinz, Fabian KLUGE, Evi BIELER, Markus ULRICH, Jörg GRÜNER, Sigfried FINK, Markus DÜRRENBERGER et René FUCHS. « Trunk anatomy of asymptomatic and symptomatic grapevines provides insights into degradation patterns of wood tissues caused by Esca-associated pathogens ». Phytopathologia Mediterranea 61, n^o 3 (25 novembre 2022) : 451–71. http://dx.doi.org/10.36253/phyto-13154.

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Wood colonizing fungi are specialists that exploit the lignocellulose of cell wall components in host wood cylinders as a carbon sources. Some of these specialized fungi, including Fomitiporia mediterranea (Fmed) and Phaeomoniella chlamydospora (Pch), cause the disease Esca of grapevine. This disease complex includes grapevine leaf stripe disease (GLSD) of canopies and white rot and black wood streaking in trunks. The present study gained insights into the activity of Esca pathogens in host xylem of the trunk tissues at an anatomical level. Lesions with white rot and brown wood streaking were microscopically analyzed, and the structures of affected tissues were compared with intact xylem. In trunks with white rot, demarcation zones separated intact tissues from the lesions. Immediately adjacent to the demarcation zones, cell wall decomposition initiated in the xylem. At this initial stage, cavities appeared in the secondary cell walls of libriform fibres, which expanded and closely resembled the degradation pattern of soft rot. In the advanced stage, the fibre cell walls were completely decomposed, and the vessels were attacked with a degradation pattern similar to white rot. Only remnants of the xylem elements remained, forming amorphous matrices. These decomposition patterns occurred in field samples and in wood cores artificially infected with Fmed. The obvious compartmentalization of the tissue affected by Fmed indicated a defense reaction in the xylem, according to the CODIT model. In contrast, brown wood streaking affected only small groups of vessels, adjacent libriform fibres and parenchyma. Dark inclusions in cells and tyloses in vessels indicate a defense reaction against the pathogens causing brown wood streaking. Artificial inoculation of sterile wood cores with Pch confirmed the contribution of this pathogen to brown wood streaking. This research provides insights into the structural and functional anatomy of intact and infected tissues of grapevines, which clarify the etiology of Esca, and provide new knowledge for developing new approaches to control of this disease complex.

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Lambert, Carole, Ian Li Kim Khiook, Sylvia Lucas, Nadège Télef-Micouleau, Jean-Michel Mérillon et Stéphanie Cluzet. « A Faster and a Stronger Defense Response : One of the Key Elements in Grapevine Explaining Its Lower Level of Susceptibility to Esca ? » Phytopathology® 103, n^o 10 (octobre 2013) : 1028–34. http://dx.doi.org/10.1094/phyto-11-12-0305-r.

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Wood diseases like Esca are among the most damaging afflictions in grapevine. The defense mechanisms in this plant–pathogen interaction are not well understood. As some grapevine cultivars have been observed to be less susceptible to Esca than others, understanding the factors involved in this potentially stronger defense response can be of great interest. To lift part of this veil, we elicited Vitis vinifera plants of two cultivars less susceptible to Esca (‘Merlot’ and ‘Carignan’) and of one susceptible cultivar (‘Cabernet Sauvignon’), and monitored their defense responses at the leaf level. Our model of elicitation consisted in grapevine cuttings absorbing a culture filtrate of one causal agent of Esca, Phaemoniella chlamydospora. This model might reflect the early events occurring in Esca-affected grapevines. The two least susceptible cultivars showed an earlier and stronger defense response than the susceptible one, particularly with regard to induction of the PAL and STS genes, and a higher accumulation of stilbene compounds and some pathogenesis-related proteins.

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Martín, Laura, Blanca García-García et María del Mar Alguacil. « Interactions of the Fungal Community in the Complex Patho-System of Esca, a Grapevine Trunk Disease ». International Journal of Molecular Sciences 23, n^o 23 (25 novembre 2022) : 14726. http://dx.doi.org/10.3390/ijms232314726.

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Worldwide, Esca is a complex and devastating Grapevine Trunk Disease (GTD), characterized by inconstant foliar symptoms and internal wood degradation. A large range of fungal taxa have been reported as causal agents. We applied both culture-dependent and culture-independent methods (Illumina Technology and q-PCR) to investigate this concerning disease. Woods from vines with asymptomatic leaves and vines with leaf Esca symptoms were compared. Internally, different types of wood were found, from healthy wood with black necrosis to wood with white rot. A combination of leaf and wood Esca symptoms resulted in four experimental categories. Although there was no relation with symptoms, culture-independent mycobiome composition revealed Phaeomoniella chlamydospora, a GTD pathogen, as the most abundant species (detected in 85.4% of wood samples, with 14.8% relative abundance). Using TaqMan q-PCR, P. chlamydospora DNA was detected in 60.4% of samples (far from the 18.8% of positive results in the culture-dependent approach). There was a predominance of saprotrophs, even if their abundance was not affected by Esca symptoms. Concerning pathotrophs, the white rot development within grapevines was linked to the abundance of fungi belonging to the Hymenochaetaceae family. The Botryosphaeriaceae family was identified as an indicator for expression of Esca foliar symptoms. Lastly, the Aureobasidiaceae family was found to be a potential biocontrol agent for Esca, since it was most abundant in the control asymptomatic plants.

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Rolshausen, P. E., L. C. Greve, J. M. Labavitch, N. E. Mahoney, R. J. Molyneux et W. D. Gubler. « Pathogenesis of Eutypa lata in Grapevine : Identification of Virulence Factors and Biochemical Characterization of Cordon Dieback ». Phytopathology® 98, n^o 2 (février 2008) : 222–29. http://dx.doi.org/10.1094/phyto-98-2-0222.

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Eutypa lata is a vascular pathogen of woody plants. In the present study we (i) determined which component(s) of the cell wall polymers were degraded in naturally infected grapevines and in artificially inoculated grape wood blocks; (ii) compared the pattern of wood decay in the tolerant grape cv. Merlot versus the susceptible cv. Cabernet Sauvignon; and (iii) identified secondary metabolites and hydrolytic enzymes expressed by E. lata during wood degradation. Biochemical analyses and a cytochemical study indicated that glucose-rich polymers were primary targets of E. lata. Structural glucose and xylose of the hemicellulose fraction of the plant cell wall and starch were depleted in infected woods identically in both cultivars. Moreover, the more tolerant cv. Merlot always had more lignin in the wood than the susceptible cv. Cabernet Sauvignon, indicating that this polymer may play a role in disease resistance. In vitro assays demonstrated the production by E. lata of oxidases, glycosidases and starch degrading enzymes. Phytotoxic secondary metabolites were also produced but our data suggest that they may bind to the wood. Finally, we demonstrated that free glucose in liquid cultures repressed primary but not secondary metabolism.

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Bruez, Emilie, Philippe Larignon, Christophe Bertsch, Guillaume Robert-Siegwald, Marc-Henri Lebrun, Patrice Rey et Florence Fontaine. « Impacts of Sodium Arsenite on Wood Microbiota of Esca-Diseased Grapevines ». Journal of Fungi 7, n^o 7 (22 juin 2021) : 498. http://dx.doi.org/10.3390/jof7070498.

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Although sodium arsenite was widely used in Europe until its ban in 2003, its effects on microorganisms is not clearly understood. To improve our understanding of sodium arsenite curative effect on GTDs, grapevines displaying esca-foliar symptoms from different French regions (Alsace, Champagne, Languedoc) were treated or not with sodium arsenite, and analyzed for their wood microbiota. Using metabarcoding, we identified the fungal and bacterial taxa composition of microbiota colonizing woody trunk tissues. Large differences in fungal microbiota composition between treated and untreated grapevines were observed while no major impacts were observed on bacteria microbiota. The main fungal species detected in untreated necrotic woody tissues was Fomitiporia mediterranea (63–94%), a fungal pathogen associated with esca. The relative abundance of this fungal species significantly decreased after sodium arsenite treatment in the three vineyards, in particular in white-rot necrotic tissues and their borders (−90%). F. mediterranea was the most sensitive to sodium arsenite among fungi from grapevine woody tissues. These results strongly suggest that the effect of sodium arsenite on GTDs is due to its ability to efficiently and almost specifically eliminate F. mediterranea from white-rot necrotic tissues, allowing saprobic fungi to colonize the tissues previously occupied by this pathogenic fungus.

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Reveglia, Pierluigi, Regina Billones-Baaijens, Jennifer Millera Niem, Marco Masi, Alessio Cimmino, Antonio Evidente et Sandra Savocchia. « Production of Phytotoxic Metabolites by Botryosphaeriaceae in Naturally Infected and Artificially Inoculated Grapevines ». Plants 10, n^o 4 (19 avril 2021) : 802. http://dx.doi.org/10.3390/plants10040802.

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Grapevine trunk diseases (GTDs) are considered a serious problem to viticulture worldwide. Several GTD fungal pathogens produce phytotoxic metabolites (PMs) that were hypothesized to migrate to the foliage where they cause distinct symptoms. The role of PMs in the expression of Botryosphaeria dieback (BD) symptoms in naturally infected and artificially inoculated wood using molecular and analytical chemistry techniques was investigated. Wood samples from field vines naturally infected with BD and one-year-old vines inoculated with Diplodia seriata, Spencermartinsia viticola and Dothiorella vidmadera were analysed by cultural isolations, quantitative PCR (qPCR) and targeted LC-MS/MS to detect three PMs: (R)-mellein, protocatechuic acid and spencertoxin. (R)-mellein was detected in symptomatic naturally infected wood and vines artificially inoculated with D. seriata but was absent in all non-symptomatic wood. The amount of (R)-mellein detected was correlated with the amount of pathogen DNA detected by qPCR. Protocatechuic acid and spencertoxin were absent in all inoculated wood samples. (R)-mellein may be produced by the pathogen during infection to break down the wood, however it was not translocated into other parts of the vine. The foliar symptoms previously reported in vineyards may be due to a combination of PMs produced and climatic and physiological factors that require further investigation.

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Jones, E. E., D. S. Brown, C. M. Bleach, B. Pathrose, C. Barclay, M. V. Jaspers et H. J. Ridgway. « First Report of Cylindrocladiella parva as a Grapevine Pathogen in New Zealand ». Plant Disease 96, n^o 1 (janvier 2012) : 144. http://dx.doi.org/10.1094/pdis-04-11-0347.

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Isolates morphologically identified as Cylindrocladiella parva were isolated from characteristic black foot symptoms on a grapevine (Vitis vinifera) rooted on 101-14 rootstock from Central Otago in 2005 and 101-14 rootstocks from a nursery in the Auckland Region in 2007 and 2008. On potato dextrose agar, the isolates initially produced cottony, white mycelia that turned grayish cream or golden cream within 10 days, the initially tawny colony undersides becoming dark brown with age. Conidia (0 to 1 septate; 16.4 to 17.0 [16.7] × 2.3 to 2.6 [2.5] μm) and abundant chlamydospores were produced. To confirm identity of the isolates, genomic DNA was extracted and the ribosomal DNA (rDNA) and β-tubulin gene were amplified and sequenced (3,4). Sequences of the PCR products were compared with sequences in GenBank. The rDNA (535 bp) and β-tubulin (297 bp) sequences of the four isolates were 100 and 99% identical, respectively, to reported sequences of C. parva in GenBank (AY793454, grapevine isolate (4)/AY793455 for rDNA; AY793486/AY793488, grapevine isolate (4)/AY793489/HM034822 for β-tubulin). Although C. parva was previously isolated from grapevines in New Zealand (2) and rootstocks of mature grapevines, cuttings, and graft unions of grafted young grapevines in South Africa (4), its role as a pathogen of Vitis spp. has not been confirmed (2,4). However, it has been reported as a pathogen of Eucalyptus spp. (1) and was also isolated from Telopea speciosissima and Macadamia integrifolia in New Zealand (2,4). The C. parva isolates were tested as a mixed inoculum (four isolates) for pathogenicity on roots of 10 grapevine rootstock plants each of cvs. 101-14 and Schwarzmann (Sch). The rootstocks were grown in potting mix for 4 months, after which the root systems of all vines were wounded with an asparagus knife with a sharp, square tip, driven vertically down into the soil at four equidistant locations approximately 8 cm from the trunk. Each plant was inoculated with 50 ml of the mixed-isolate conidial suspension (106/ml), or 50 ml water (controls), followed by 50 ml of water. After 7 months of growth, the plants were harvested. For C. parva-inoculated plants, internal blackening of the stem base tissue was observed. Isolations from surface-sterilized trunk bases recovered C. parva from four and nine plants of 101-14 and Sch, respectively, with C. parva infections in 25 and 48%, respectively, of the four wood pieces taken per plant. Plants inoculated with water had no blackening and no C. parva was isolated from their stem bases. Mean shoot dry weights of inoculated plants (17.9 and 15.0 g for 101-14 and Sch, respectively) were significantly lower (P = 0.035) than noninoculated controls (26.5 and 20.0 g for 101-14 and Sch, respectively). Mean root dry weights were reduced by C. parva inoculation, although not significantly (32.7 and 27.0 g for C. parva inoculated 101-14 and Sch, respectively, and 36.2 and 27.4 g for control 101-14 and Sch, respectively). To our knowledge, this is the first report of C. parva as a pathogen of grapevines (2,4) and suggests that along with Cylindrocarpon spp., C. parva is part of the pathogen complex responsible for black foot of grapevines. References: (1) P. W. Crous et al. Plant Pathol. 42:302, 1993. (2) P. D. Gadgil et al. Fungi on Trees and Shrubs in New Zealand. Fungal Diversity Press, Hong Kong, 2005. (3) N. L. Glass and G. C. Donaldson. Appl. Environ. Microbiol. 61:1323, 1995. (4) G. J. van Coller et al. Australas. Plant Pathol. 34:489, 2005.

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Sanderlin, R. S., et R. A. Melanson. « Reduction of Xylella fastidiosa Transmission Through Pecan Scion Wood by Hot-Water Treatment ». Plant Disease 92, n^o 7 (juillet 2008) : 1124–26. http://dx.doi.org/10.1094/pdis-92-7-1124.

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Pecan (Carya illinoinensis) bacterial leaf scorch disease, caused by the bacterium Xylella fastidiosa, causes leaf loss and reduction in yield of pecans. One of the ways that the pathogen infects newly developing trees is by graft-transmission through infected scion wood. Submersion of pecan scion wood in 46°C water for 30 min greatly reduced transmission of X. fastidiosa following grafting. During a 2-year study with potted rootstock grafted to either hot-water-treated or nontreated scion wood collected from limbs of ‘Cape Fear’ pecan infected with X. fastidiosa, the pathogen was detected in 21% of the trees that developed from the nontreated scion wood and 0.7% of the trees from the hot-water-treated scions. The hot-water treatment of 46°C for 30 min did not affect graft success. Likewise, scion diameter had no effect on success of grafting or on the efficacy of hot-water treatment. Similar hot-water treatments have been efficacious in elimination of X. fastidiosa and some other pathogens from grapevine cuttings. The use of the hot-water treatment demonstrated in this report could be helpful to individual pecan growers and nurseries that use scion wood that may be infected with X. fastidiosa to reduce the occurrence of pecan bacterial leaf scorch disease in new trees.

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Labois, Clément, Kim Wilhelm, Hélène Laloue, Céline Tarnus, Christophe Bertsch, Mary-Lorène Goddard et Julie Chong. « Wood Metabolomic Responses of Wild and Cultivated Grapevine to Infection with Neofusicoccum parvum, a Trunk Disease Pathogen ». Metabolites 10, n^o 6 (4 juin 2020) : 232. http://dx.doi.org/10.3390/metabo10060232.

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Grapevine trunk diseases (GTDs), which are associated with complex of xylem-inhabiting fungi, represent one of the major threats to vineyard sustainability currently. Botryosphaeria dieback, one of the major GTDs, is associated with wood colonization by Botryosphaeriaceae fungi, especially Neofusicoccum parvum. We used GC-MS and HPLC-MS to compare the wood metabolomic responses of the susceptible Vitis vinifera subsp. vinifera (V. v. subsp. vinifera) and the tolerant Vitis vinifera subsp. sylvestris (V. v. subsp. sylvestris) after artificial inoculation with Neofusicoccum parvum (N. parvum). N. parvum inoculation triggered major changes in both primary and specialized metabolites in the wood. In both subspecies, infection resulted in a strong decrease in sugars (fructose, glucose, sucrose), whereas sugar alcohol content (mannitol and arabitol) was enhanced. Concerning amino acids, N. parvum early infection triggered a decrease in aspartic acid, serine, and asparagine, and a strong increase in alanine and β-alanine. A trend for more intense primary metabolism alteration was observed in V. v. subsp. sylvestris compared to V. v. subsp. vinifera. N. parvum infection also triggered major changes in stilbene and flavonoid compounds. The content in resveratrol and several resveratrol oligomers increased in the wood of both subspecies after infection. Interestingly, we found a higher induction of resveratrol oligomer (putative E-miyabenol C, vitisin C, hopeaphenol, ampelopsin C) contents after wood inoculation in V. v. subsp. sylvestris.

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Reis, Pedro, Vincenzo Mondello, Inês Diniz, Artur Alves, Cecília Rego et Florence Fontaine. « Effect of the Combined Treatments with LC2017 and Trichoderma atroviride Strain I-1237 on Disease Development and Defense Responses in Vines Infected by Lasiodiplodia theobromae ». Agronomy 12, n^o 5 (21 avril 2022) : 996. http://dx.doi.org/10.3390/agronomy12050996.

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Grapevine trunk diseases constitute one of the major problems for viticulture worldwide, with Botryosphaeria dieback considered as one of the most important of these diseases. In this work, we aimed to (i) evaluate the effect of the combination of two products, Esquive® (a Trichoderma-based product) and LC2017 (a low-copper-based product), in the control of Lasiodiplodia theobromae, by evaluating the internal lesion length caused by inoculation of this pathogen on greenhouse kept grapevines of cvs Cabernet Sauvignon and Touriga Nacional and, (ii) investigating their elicitor effect on plant defense responses, through the analysis of the expression of a set of genes. The pathogen was always re-isolated from the infected tissues and was able to cause wood discoloration. Touriga Nacional exhibited longer lesions than Cabernet Sauvignon, and the application of both products did not appear to reduce lesion length when compared to LC2017 applied alone. The elicitor effect of LC2017 on plant defense was confirmed by gene expression analysis, and no significant differences were found between plants treated with LC2017 and with both products. Moreover, a specific response related to the cultivar was verified, but this apparently unique interaction between product, cultivar and pathogen remains to be further investigated.

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Cortesi, Paolo, Michael Fischer et Michael G. Milgroom. « Identification and Spread of Fomitiporia punctata Associated with Wood Decay of Grapevine Showing Symptoms of Esca ». Phytopathology® 90, n^o 9 (septembre 2000) : 967–72. http://dx.doi.org/10.1094/phyto.2000.90.9.967.

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A full understanding of the pathology of esca, a chronic disease of grapevines, has been problematic, in part because the identity of the pathogen (or pathogens) has been difficult to determine. The wood decay symptoms of esca have been most often associated with Phellinus igniarius or Fomitiporia punctata. However, Koch's postulates have not been completely fulfilled because symptoms take many years to develop. The goal of this study was to determine the identity and mode of spread of basidiomycetes associated with wood decay in vines showing esca symptoms in Italian vineyards. Vineyards were intensively studied for the presence of basidiocarps, and mycelium was isolated from symptomatic vines. Fruiting bodies were identified by morphology, while mycelial isolates were identified by restriction fragment length polymorphism analysis of the internal transcribed spacer region of the nuclear ribosomal RNA gene cluster. Fomitiporia punctata fruiting bodies and mycelium were associated with approximately 50% of the vines showing esca symptoms in two vineyards; P. igniarius was not found in any samples. Fruiting bodies of F. punctata were found in five of six vineyards examined, but at low frequencies except in one vineyard. The diversity of somatic incompatibility types was very high; isolates from almost every vine had different somatic incompatibility types. With few exceptions, symptomatic and dead vines were not spatially aggregated within 12 vineyards. The combination of diverse somatic incompatibility types and lack of spatial aggregations are not consistent with the hypothesis that the disease is spread clonally through roots or by pruning tools. The correct identity of basidiomycetes associated with wood decay of vines with esca symptoms is important for understanding the epidemiology of this disease because F. punctata is found commonly on many woody hosts in Europe, which may represent a potential inoculum source for this disease.

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Czemmel, Stefan, Erin R. Galarneau, Renaud Travadon, Andrew J. McElrone, Grant R. Cramer et Kendra Baumgartner. « Genes Expressed in Grapevine Leaves Reveal Latent Wood Infection by the Fungal Pathogen Neofusicoccum parvum ». PLOS ONE 10, n^o 3 (23 mars 2015) : e0121828. http://dx.doi.org/10.1371/journal.pone.0121828.

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Martin, M. T., L. Martin, M. T. de-Francisco et R. Cobos. « First Report of Lasidiplodia theobromae and Cryptovalsa ampelina Associated with Grapevine Decline from Castilla y León, Spain ». Plant Disease 93, n^o 5 (mai 2009) : 545. http://dx.doi.org/10.1094/pdis-93-5-0545c.

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Symptoms of grapevine decline were surveyed. Samples from mature vines exhibiting external symptoms of Eutypa dieback and Esca were collected, as were young plants with and without external symptoms, and fungal isolations were performed. In 2007, 3-year-old grapevines (cv. Tempranillo grafted onto 110R rootstock) with low vigor, reduced foliage, and vascular streaking in the wood were observed. Small pieces of discolored wood were placed onto malt extract agar supplemented with 0.25 g/liter of chloramphenicol, incubated at 25°C, and resulting colonies were transferred to potato dextrose agar (PDA). Isolates were characterized by abundant aerial and fast-growing mycelium covering the plate surface after 3 days, mycelium became dark green. Pycnidia contained thick-walled, aseptate conidia 15 to 35 × 10 to 15 μm. Lasidiplodia theobromae was identified based on morphological characteristics (3) and confirmed by banding patterns obtained after the digestion of the 1,200-bp amplicon generated with ITS1 and NL4 primers (2) using restriction endonucleases (2). Single-spore cultures were generated and DNA sequences of the rDNA internal transcribed spacer region, partial sequence of the 5′ end of the β-tubulin gene, and a fragment of the elongation factor further confirmed the identification and revealed genetic similarity with other isolates of L. theobromae. A sequence of each fragment was deposited in GenBank with Accession Nos. EU600925, EU597297, and EU597298, respectively. Pathogenicity tests were conducted on four replicate rootstocks (110R) and 15 canes of current-season growth (cv. Tempranillo). Plants were inoculated with an agar plug containing L. theobromae; controls were treated with agar only. Grapevines were maintained in a greenhouse at 20 to 25°C. After 3 months, L. theobromae was reisolated from internal vascular lesions in 100 and 66% of inoculated rootstocks and canes, respectively. Control plants were asymptomatic and L. theobromae was not recovered. Using the same methodology, a fungus identified based on morphological characteristics in culture as Cryptovalsa ampelina (1) was isolated from grapevines (cv. Tempranillo) planted in 1987. Cultures in PDA were white to creamy white and cottony with diffuse margins. Colonies covered the 90-mm-diameter petri dish surface in 5 days. Conidia were 20 to 23 × 1 to 1.5 μm, unicellular, hyaline, and filiform. PCR amplifications of the DNA extracts of C. ampelina with Camp-1 and Camp-2R primers gave a characteristic DNA fragment of 300 bp (3) and DNA sequences of the ITS4-ITS5 amplicons (GenBank Accession No. EU597296) confirmed the identification. For the first time, the 5′ end of the β-tubulin gene was sequenced and deposited in GenBank (Accession No. EU600926). Pathogenicity tests were conducted as described above for L. theobromae. Both pathogens were examined in the same experiment. C. ampelina was reisolated from internal brown streaking lesions in 25% of the rootstocks and 33% of the canes. Control plants exhibited no symptoms. L. theobromae appeared to be a more aggressive pathogen than C. ampelina on grapevine with more internal brown streaking and greater recovery of pathogen from inoculated samples. To our knowledge, this is the first report of L. theobromae and C. ampelina causing grapevine decline in Castilla y León. References: (1) J. Luque et al. Phytopathol. Mediterr. 45:S101, 2006. (2) M. T. Martin and R. Cobos. Phytopathol. Mediterr. 46:18, 2007. (3) D. Pavlic et al. Stud. Mycol. 50:313, 2004.

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Scheck, H. J., S. J. Vasquez, W. D. Gubler et D. Fogle. « First Report of Three Phaeoacremonium spp. Causing Young Grapevine Decline in California ». Plant Disease 82, n^o 5 (mai 1998) : 590. http://dx.doi.org/10.1094/pdis.1998.82.5.590c.

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A grapevine decline of unknown etiology is currently under investigation in California. Two- to 5-year-old vines show low vigor with undersized trunks, short internodes, uneven wood maturity, sparse foliage, and stunted, chlorotic leaves with interveinal chlorosis and necrosis. Trunks viewed in cross section show dark streaking in few to most of the vascular elements. Pith is compacted and discolored; the surrounding wood is dry with a silvery sheen. Primary roots also show dark streaking in the vascular elements and total root biomass is reduced. Phaeoacremonium spp. were consistently isolated from the roots, crowns, and lower portions of the rootstocks of declining vines but not from adjacent healthy vines. Phaeoacremonium spp. grew slowly out of infected tissues, but sporulated abundantly in culture. Identification was verified from a published key (1). Phaeoacremonium chlamydosporum and P. inflatipes were isolated throughout the northern and central California production areas, but P. aleophilum was isolated only in Riverside County. Koch's postulates were completed for Phaeoacremonium spp. by dipping roots of 2-month-old Carignane grape seedlings (n = 80) in a 108 spores per ml suspension for 30 min. Plants were potted in an artificial soil mix and held in a growth chamber at 25°C. Over 50% of plants inoculated with Phaeo-acremonium spp. developed root, stem, and vascular symptoms within 8 weeks. Each of the individual pathogen species was reisolated from over 75% of the inoculated plants but never from the controls. Similarly, all three Phaeoacremonium spp. are associated with wilt and decline diseases in grapevines in Africa (1) and Europe (2) but this is the first report in North America. While several names for this disease have been used previously with older grapevines, including Esca, apoplexy, and black measles (3), we propose using Phaeoacremonium grapevine decline to describe the diseases caused by P. aleophilum, P. chlamydosporum, and P. inflatipes on young vines. References: (1) P. W. Crous et al. Mycologia 88:786, 1996. (2) P. Larignon and B. Dubos. Euro. J. Plant Pathol. 103:147, 1997. (3) R. Pearson and A. Goheen. 1988. Compendium of Grape Diseases. American Phytopathological Society, St. Paul, MN.

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Martín, M. T., M. J. Cuesta et L. Martín. « Development of SCAR Primers for PCR Assay to Detect Diplodia seriata ». International Scholarly Research Notices 2014 (28 septembre 2014) : 1–9. http://dx.doi.org/10.1155/2014/824106.

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The aim of this study was to develop primer pairs for Diplodia seriata identification, one of the most common fungal species associated with grapevine decline in Castilla y León (Spain). Genetic variability of selected isolates of D. seriata was estimated. A molecular marker was generated from a random amplified polymorphic DNA (RAPD) fragment. PCR products of around 1200 bp were obtained with OPE20 primer. The PCR products were cloned and sequenced. The sequences were compared and a fragment of 1207 bp was used to design primer pairs. Two primer pairs were selected (DS3.8 S3-DS3.8 R6 and DS3.8 S3-DS3.8 R4) that amplified a single DNA product of 634 bp and 233 bp, respectively, with D. seriata isolates. No amplification was obtained for any of the 57 isolates of other species. The designed SCAR primer pairs allowed a rapid detection of D. seriata, and were able to detect 0.1 pg of the target DNA. Detection was specific and sensitive for D. seriata. The established protocols detected these fungi in naturally infected grapevines after DNA purification. Diplodia seriata was detectable without DNA purification and isolation in 62.5% to 75% of reactions. The detection of this pathogen in wood samples has great potential for use in pathogen-free certification schemes.

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Billones, R. G., H. J. Ridgway, E. E. Jones et M. V. Jaspers. « First Report of Neofusicoccum macroclavatum as a Canker Pathogen of Grapevine in New Zealand ». Plant Disease 94, n^o 12 (décembre 2010) : 1504. http://dx.doi.org/10.1094/pdis-07-10-0494.

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In a 2008 survey, 120 isolates of the Botryosphaeriaceae were recovered from a representative subsample of Vitis vinifera plants and propagation materials collected in nine New Zealand grapevine nurseries. Isolates were identified by amplified ribosomal DNA restriction analysis (ARDRA) (1) as Neofusicoccum luteum (56%), N. parvum (18%), N. australe (8%), Diplodia mutila (7%), Botryosphaeria dothidea (5%), D. seriata (3%), and N. ribis (2%). One isolate (M353) from 1 cm below the graft union of a nonsymptomatic 1-year-old grafted plant from the Nelson Region was not identified by ARDRA and was morphologically distinct from all others. Mycelium produced by the novel isolate on potato dextrose agar (PDA) was initially moderately dense, flat, and white and turned olivaceous brown within 10 days. The isolate did not produce pycnidia in PDA or prune extract agar, but when grown in water agar with sterile pine needles for 8 weeks at 25°C and a 12-h light/dark regimen, small, black pycnidia covered with mycelium were produced but no conidia were observed. To identify the novel fungus, genomic DNA was extracted and the ribosomal DNA (rDNA), β-tubulin gene, and elongation factor α-1 gene were amplified and sequenced (4). The sequences of the PCR products were compared with sequences present on GenBank. The rDNA (503 bp), β-tubulin (371 bp), and elongation factor α-1 gene (227 bp) sequences of M353 were 100% identical to reported sequences of N. macroclavatum on GenBank (Accession No. DQ093199/198/196 for rDNA, DQ093207/206 for β-tubulin, and DQ093219/217 for elongation factor α-1). These genes differed from the same genes in other Neofusicoccum species by at least 11, 2, and 3 base pairs, respectively. The N. macroclavatum isolate was tested for pathogenicity on wounded grapevine (Sauvignon blanc) green shoots and 1-year-old rooted canes (n = 4 per plant type) using mycelium plugs from a 4-day-old PDA culture. Sterile agar was used for the negative control. Green shoots inoculated with N. macroclavatum developed brown lesions with an average length of 40.5 mm 6 days after inoculation. Bark from inoculated 1-year-old canes was peeled off 28 days after inoculation and brown-to-black lesions on the wood, with an average length of 52 mm, were observed. Control plants produced no lesions. The pathogen was consistently reisolated from the inoculated plants while none were found in negative control plants. To our knowledge, this is the first report of N. macroclavatum as a pathogen of grapevines and the first report of its presence in New Zealand (3). N. macroclavatum was first reported as a pathogen of Eucalyptus globulus in Western Australia in 2005 and has not been reported as a pathogen of grapevines (2). References: (1) A. Alves et al. FEMS Microbiol. Lett. 245:221, 2005. (2) T. T. Burgess et al. Australas. Plant Pathol. 34:557, 2005. (3) J. Sammonds et al. N. Z. Plant Prot. 62:248, 2009. (4) B. Slippers et al. Mycologia 96:83, 2004.

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Vizitiu, Diana Elena, Daniela Ionela Sardarescu, Irina Fierascu, Radu Claudiu Fierascu, Liliana Cristina Soare, Camelia Ungureanu, Elena Cocuta Buciumeanu, Ionela Catalina Guta et Letitia Mariana Pandelea. « Grapevine Plants Management Using Natural Extracts and Phytosynthesized Silver Nanoparticles ». Materials 15, n^o 22 (18 novembre 2022) : 8188. http://dx.doi.org/10.3390/ma15228188.

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Starting from the well-known antimicrobial properties of silver nanoparticles, the goal of this study is to evaluate the influence of two “green” recipes, namely an alcoholic extract of Dryopteris filix-mas (L.) Schott and a dispersion of silver nanoparticles phytosynthesized using the extract on grapevine pathogens. The influence of some grapevine parameters (pith/wood rapport, soluble sugars, starch, total sugars, total water content, length of young shoots, number of grapes) in field experiments was also studied. The study was conducted on four clones (Feteasca alba 97 St., Feteasca neagra 6 St., Feteasca regala 72 St., and Cabernet Sauvignon 131 St.) located in vegetation pots inside a greenhouse. For the phytosynthesis of the silver nanoparticles (AgNPs) we used a scaled-up technology, allowing us to obtain large quantities of nanoparticles-containing solution. The AgNPs analysis by X-ray diffraction and transmission electron microscopy confirmed the synthesis of spherical and quasi-spherical nanoparticles of 17 nm average diameter and 6.72 nm crystallite size. The field experiments registered different responses of the four clones to the treatment, using both the natural extracts and phytosynthesized nanoparticles solution. Both recipes exhibited a protective effect against the Uncinula necator pathogen. For the treatment using phytosynthesized nanoparticles, significant increases in the pith/wood ratio for white wine clones (Feteasca alba 97 St. and Feteasca regala 72 St.) were observed. The biochemical analyses revealed other significant increases of soluble sugars (red wine clones—Feteasca neagra and Cabernet Sauvignon/second year), starch (Feteasca alba and Cabernet Sauvignon in 2021 for both clones), total sugars (Feteasca alba and Feteasca neagra in 2021 for both clones), and of total water content (Feteasca alba and Feteasca neagra in 2021 for both clones), respectively. The applied treatments also led to an increase of young shoots length and grape numbers for all clones as compared to the control (chemical pesticide), which would suggest a potential biostimulant effect of the recipes.

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Rolshausen, P. E., D. S. Akgül, R. Perez, A. Eskalen et C. Gispert. « First Report of Wood Canker Caused by Neoscytalidium dimidiatum on Grapevine in California ». Plant Disease 97, n^o 11 (novembre 2013) : 1511. http://dx.doi.org/10.1094/pdis-04-13-0451-pdn.

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In May 2012 in the Coachella valley, Riverside County, California, the decline of vines in table grape (Vitis vinifera) vineyards was observed. Foliar symptoms consisted of shoot blight with wilting and necrosis of leaves and drying and shriveling of berries. In some cases, the entire vine collapsed in the middle of the growing season (apoplexia). Wood cankers in the spurs, cordons, and trunks of affected vines were also present. The nine isolates recovered from the cankers were identified as Neoscytalidium dimidiatum (Penz.) Crous & Slippers based on morphological characteristics and DNA sequence comparisons. Two isolates were grown on potato dextrose agar (PDA) medium and a total of 50 conidia were measured per isolate. Conidia were ellipsoid to ovoid, with a truncate base and an acutely rounded apex, initially aseptate, becoming brown and two-celled at maturity, 7.2 ± 1.2 μm × 3.8 ± 0.4 μm. The rDNA internal transcribed spacer (ITS), and β-tubulin (BT) loci were amplified using primer pairs and methods previously described (4). A total of five isolates were sequenced. The DNA sequences of one N. dimidiatum grapevine isolate (UCR-Neo1) were deposited in the GenBank database (ITS, KC937066; BT, KC937067). Pathogenicity tests were performed by inoculating 12 grape cuttings cv. Thompson Seedless with isolate UCR-Neo1 and 12 control cuttings with sterile medium using a technique previously described (1). The experiment was repeated twice. After 20 weeks of incubation period in the greenhouse, the lesions length produced by N. dimidiatum averaged 13.5 mm and was significantly longer (P < 0.05) from the control (average 3 mm). N. dimidiatum was reisolated from all the inoculated plants and identified by colony morphology. The incidence of N. dimidiatum in table grape vineyards of the Coachella valley has been estimated at 15%, with nine vines infected out of 60 vines total. This pathogen has been identified in California in walnut nursery causing the death of trees due to the development of canker at the graft union (2). N. dimidiatum has also been identified as the causal agent of shoot blight, canker, and gummosis on citrus in Italy (3). The crop is also being grown in the Coachella valley and these findings warrant further investigation in order to determine the host range, distribution, and incidence of this pathogen in the area. References: (1) K. Baumgartner et al. Plant Dis. 97:912, 2013. (2) S. F. Chen et al. Plant Dis. 97:993, 2013. (3) G. Polizzi et al. Plant Dis 93:1215, 2009. (4) J. R. Urbez-Torres et al. Plant Dis. 92:519, 2008.

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Rusin, Carine, Fabio Rossi Cavalcanti, Patrícia Carla Giloni de Lima, Cacilda Márcia Duarte Rios Faria, Marcus André Kurtz Almança et Renato Vasconcelos Botelho. « Control of the fungi Lasiodiplodia theobromae, the causal agent of dieback, in cv. syrah grapevines ». Acta Scientiarum. Agronomy 43 (14 août 2020) : e44785. http://dx.doi.org/10.4025/actasciagron.v43i1.44785.

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Grapevine trunk diseases are among the most important limiting factors of worldwide viticulture. In this context, we aimed to verify the effect of chemical fungicides, biological agents and plant extracts on the control of Lasiodiplodia theobromae in pruning wounds and their physiological effects in cv. Syrah grapevines. Plant extracts (clove, cinnamon, garlic, rosemary and lemongrass), commercial fungicides (difeconazole, tebuconazole, mancozeb, sulfur, pyraclostrobin, fosetyl-Al, and azoxystrobin), chitosan, Trichoderma harzianum and Bacillus subtilis were used for the in vitro trials. The protection of pruning wounds in the potted vines was studied using fosetyl-Al, tebuconazole, Trichoderma harzianum, Bacillus subtilis, garlic extract and clove extract. The experiments were carried out through two vegetative cycles: 2015/2016 and 2016/2017. The length of wood discoloration, pathogen re-isolation percentage, fresh mass of the pruning material, peroxidase activity, fluorescence, chlorophyll index, phenological stages, shoot length and leaf area were evaluated. The treatments with clove, garlic extract, tebuconazole, pyraclostrobin, mancozeb, fosetyl-Al and B. subtilis reduced mycelial growth by more than 90%. In the grapevines, the use of T. harzianum decreased the re-isolation of L. theobromae, but no differences were verified for the other plant evaluations. We concluded that the use of T. harzianum would be a potential option for wound protection without altering the physiological aspects of cv. Syrah grapevines.

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Landi, Lucia, Sergio Murolo et Gianfranco Romanazzi. « Colonization of Vitis spp. Wood by sGFP-Transformed Phaeomoniella chlamydospora, a Tracheomycotic Fungus Involved in Esca Disease ». Phytopathology® 102, n^o 3 (mars 2012) : 290–97. http://dx.doi.org/10.1094/phyto-06-11-0165.

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To evaluate wood colonization and interactions with Vitis spp. of Phaeomoniella chlamydospora, a fungal agent involved in Esca disease, isolate CBS 229.95 was transformed using a pCT74 construct which contained the genetic markers for synthetic green fluorescent protein (sGFP) and hygromycin B phosphotransferase. Nine stable P. chlamydospora fungal transformants (Pch-sGFP lines) were obtained using polyethylene-glycol-mediated transformation of protoplasts. These were characterized for sgfp and hygromycin B phosphotransferase (hph) genome insertions and for sGFP fluorescence emission, using quantitative polymerase chain reaction and fluorimetric systems, respectively. No correlation was observed between sgfp copy number genome insertion and sGFP fluorescence expression. Cuttings of Vitis vinifera ‘Montepulciano’, ‘Verdicchio’, ‘Sangiovese’, ‘Biancame’, and ‘Cabernet Sauvignon’; and the grapevine rootstocks ‘Kober 5BB’, ‘SO4’, ‘420A’, ‘1103P’, and V. rupestris were inoculated by immersion in a conidial suspension of the selected fungal Pch-sGFP71 line and incubated at 4 ± 1 and 25 ± 1°C. Wood colonization was estimated through epifluorescence microscopy and was affected by incubation temperature. After 6 months at 4 ± 1°C, the fungal growth was completely inhibited. At 25 ± 1°C, the highest extent of wood colonization was recorded in Montepulciano and Verdicchio, with the lowest in the rootstocks SO4 and V. rupestris. The expression of the Pch-sGFP71 transformed line was localized in the xylem area, primarily around the vessels. The use of sGFP-transformed P. chlamydospora helped to clarify different aspects associated with the location of this pathogen in grapevine tissue, before disease symptom expression.

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Besoain, X., C. Torres, G. A. Díaz et B. A. Latorre. « First Report of Neofusicoccum australe Associated with Botryosphaeria Canker of Grapevine in Chile ». Plant Disease 97, n^o 1 (janvier 2013) : 143. http://dx.doi.org/10.1094/pdis-07-12-0652-pdn.

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A survey of trunk diseases was conducted in 2010 in vineyards (n = 14) in central Chile (latitude 33°51′ to 36°30′), specifically of Vitis vinifera ‘Cabernet Sauvignon,’ which is the main wine-grape cultivar (38,806 ha) in Chile. The following symptoms of trunk disease were observed in 5- to 19-year-old grapevines: short internodes, dead spurs, dead cordons (arms), and shoot dieback. Upon cutting into cordons and trunks of symptomatic vines, brown, V-shaped cankers of hard consistency were observed. A total of 56 wood cankers were collected, and small pieces of symptomatic wood (approximately 4 mm in diameter) taken from the canker margin were surface disinfected (75% ethanol, 30 s) and placed on acidified PDA (0.5 ml of 96% lactic acid per liter; APDA), which was incubated for 4 to 7 days at 24°C. Colonies, tentatively identified as a species within the Botryosphaeriaceae based on the presence of whitish-to-gray aerial mycelium and exhibiting rapid growth (4 to 5 cm colony diameter in 48 h), were hyphal-tip purified to APDA for identification. Colonies produced globose, black pycnidia with unicellular, hyaline, ellipsoidal, densely granulate, externally smooth, and thin-walled conidia of 17.0 ± 0.7 ± 6.7 ± 0.4 μm (n = 20). A yellow pigmentation was observed at the center of 48-h colonies on APDA. Morphologically, these isolates were identified as Neofusicoccum australe (Slippers, Crous & M.J. Wingfield) Crous, Slippers & A.J.L. Phillips (2,3). BLASTn searches of the ITS rDNA region, amplified with PCR primers ITS4/ITS5 (532 bp), and a 400-bp section of the beta-tubulin subunit 2 gene amplified with primers Bt2a and Bt2b of N. australe (GenBank Accession No. JX290091 and JX679868, respectively) revealed 99% similarity with the ITS and beta-tubulin sequences of N. australe reference strains EF638778 and HQ392761, respectively. Pathogenicity tests were conducted using N. australe isolate Vid1559 on 2-year-old Cabernet Sauvignon plants (n = 4), which were inoculated by wounding the woody stem with a scalpel approximately 1 cm below the most basal bud, placing an 8-mm mycelial plug taken from a 7-day culture into the wound, and then sealing the wound with Parafilm. Non-inoculated controls (n = 4) were ‘mock’ inoculated with sterile agar plugs. After 3 months under field conditions, during spring and summer, the woody stems were examined for vascular discoloration (VD), characteristic of a wood canker. Inoculated plants had stems with light-brown, necrotic VD with a mean length of 15.2 cm, measured from the inoculation point. No VD was observed on the controls. N. australe was reisolated from 100% of the inoculated plants, completing Koch's postulates. Of 14 vineyards surveyed, 8% were infected with N. australe. N. australe is known as a trunk pathogen of grape (4), and other species of Botryosphaeriaceae have been associated with grapevine trunk disease in Chile (1). To our knowledge, this is the first report of N. australe causing Botryosphaeria canker of grape in Chile, where the pathogen is previously reported on blueberry (2). References: (1) G. A. Díaz et al. Plant Dis. 95:1032, 2011. (2) J. G. Espinoza et al. Plant Dis. 92:1407, 2008. (3) Slippers et al. Mycologia 96:1030, 2004. (4) J. R. Úrbez-Torres Phytopathol. Mediterr. 50:S5, 2011.

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Kwaśna, Hanna, Wojciech Szewczyk, Marlena Baranowska, Ewa Gallas, Milena Wiśniewska et Jolanta Behnke-Borowczyk. « Mycobiota Associated with the Vascular Wilt of Poplar ». Plants 10, n^o 5 (28 avril 2021) : 892. http://dx.doi.org/10.3390/plants10050892.

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In 2017, a 560-ha area of hybrid poplar plantation in northern Poland showed symptoms of tree decline. The leaves appeared smaller, yellow-brown, and were shed prematurely. Twigs and smaller branches died without distinct cankers. Trunks decayed from the base. The phloem and xylem showed brown necrosis. Ten percent of the trees died 1–2 months after the first appearance of the symptoms. None of these symptoms were typical for known poplar diseases. The trees’ mycobiota were analysed using Illumina sequencing. A total of 69 467 and 70 218 operational taxonomic units (OTUs) were obtained from the soil and wood. Blastocladiomycota and Chytridiomycota occurred only in the soil, with very low frequencies (0.005% and 0.008%). Two taxa of Glomeromycota, with frequencies of 0.001%, occurred in the wood. In the soil and wood, the frequencies of Zygomycota were 3.631% and 0.006%, the frequencies of Ascomycota were 45.299% and 68.697%, and the frequencies of Basidiomycota were 4.119% and 2.076%. At least 400 taxa of fungi were present. The identifiable Zygomycota, Ascomycota, and Basidiomycota were represented by at least 18, 263 and 81 taxa, respectively. Many fungi were common to the soil and wood, but 160 taxa occurred only in soil and 73 occurred only in wood. The root pathogens included species of Oomycota. The vascular and parenchymal pathogens included species of Ascomycota and of Basidiomycota. The initial endophytic character of the fungi is emphasized. Soil, and possibly planting material, may be the sources of the pathogen inoculum, and climate warming is likely to be a predisposing factor. A water deficit may increase the trees’ susceptibility. The epidemiology of poplar vascular wilt reminds grapevine trunk diseases (GTD), including esca, black foot disease and Petri disease.

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Pildain, M. B., G. A. Pérez, G. Robledo, D. B. Pappano et M. Rajchenberg. « Arambarriathe pathogen involved in canker rot ofEucalyptus, native trees wood rots and grapevine diseases in the Southern Hemisphere ». Forest Pathology 47, n^o 6 (23 novembre 2017) : e12397. http://dx.doi.org/10.1111/efp.12397.

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Sánchez-Hernández, Eva, Natalia Langa-Lomba, Vicente González-García, José Casanova-Gascón, Jesús Martín-Gil, Alberto Santiago-Aliste, Sergio Torres-Sánchez et Pablo Martín-Ramos. « Lignin–Chitosan Nanocarriers for the Delivery of Bioactive Natural Products against Wood-Decay Phytopathogens ». Agronomy 12, n^o 2 (12 février 2022) : 461. http://dx.doi.org/10.3390/agronomy12020461.

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The use of nanocarriers (NCs), i.e., nanomaterials capable of encapsulating drugs and releasing them selectively, is an emerging field in agriculture. In this study, the synthesis, characterization, and in vitro and in vivo testing of biodegradable NCs loaded with natural bioactive products was investigated for the control of certain phytopathogens responsible for wood degradation. In particular, NCs based on methacrylated lignin and chitosan oligomers, loaded with extracts from Rubia tinctorum, Silybum marianum, Equisetum arvense, and Urtica dioica, were first assayed in vitro against Neofusicoccum parvum, an aggressive fungus that causes cankers and diebacks in numerous woody hosts around the world. The in vitro antimicrobial activity of the most effective treatment was further explored against another fungal pathogen and two bacteria related to trunk diseases: Diplodia seriata, Xylophilus ampelinus, and Pseudomonas syringae pv. syringae, respectively. Subsequently, it was evaluated in field conditions, in which it was applied by endotherapy for the control of grapevine trunk diseases. In the in vitro mycelial growth inhibition tests, the NCs loaded with R. tinctorum resulted in EC90 concentrations of 65.8 and 91.0 μg·mL−1 against N. parvum and D. seriata, respectively. Concerning their antibacterial activity, a minimum inhibitory concentration of 37.5 μg·mL−1 was obtained for this treatment against both phytopathogens. Upon application via endotherapy on 20-year-old grapevines with clear esca and Botryosphaeria decay symptoms, no phytotoxicity effects were observed (according to SPAD and chlorophyll fluorescence measurements) and the sugar content of the grape juice was not affected either. Nonetheless, the treatment led to a noticeable decrease in foliar symptoms as well as a higher yield in the treated arms as compared to the control arms (3177 vs. 1932 g/arm), suggestive of high efficacy. Given the advantages in terms of controlled release and antimicrobial product savings, these biodegradable NCs loaded with natural extracts may deserve further research in large-scale field tests.

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Kaliternam, J., T. Milicevic, D. Bencic et B. Duralija. « First Report of Neofusicoccum parvum Associated with Grapevine Trunk Diseases in Croatia ». Plant Disease 97, n^o 12 (décembre 2013) : 1656. http://dx.doi.org/10.1094/pdis-03-13-0283-pdn.

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In September 2010, during survey of diseased grapevines (Vitis vinifera L.) in vineyards at localities Zmajevac (BZ), Orahovica (SO), Cilipi (KC), and Novalja (PN), symptoms characteristic of grapevine trunk diseases (GTD) (3) were observed, showing on cross-sectioned cordons and trunks as brown, wedge-shaped perennial cankers and/or dark streaking of the wood. In Croatia, these symptoms were traditionally associated with Eutypa Tul. & C.Tul. and with fungi from Diaporthaceae (2). From affected grapevines (cvs. Grasevina, Pinot bijeli, Malvazija dubrovacka, and Gegic), samples of symptomatic cordons and trunks were collected (n ≥ 35). To isolate the causal agents from the samples, woodchips of symptomatic tissue, surface-sterilized in 2% sodium hypochlorite for 2 min, were placed on potato dextrose agar amended with streptomycin sulphate (50 μg/ml) and incubated for 7 days at 25°C in darkness. A percentage of samples (72, 15, 27, and 54% from BZ, SO, KC, and PN, respectively) yielded fungal colonies with abundant aerial mycelium, initially white, but turning olivaceous grey after 5 days. From these colonies, monohyphal isolates were obtained and pycnidial formation stimulated by cultivation on 2% water agar with stems of plant species Foeniculum vulgare Mill. at 25°C under diffuse light for 3 weeks. Pycnidia contained conidia that were hyaline, unicellular, ellipsoid with round apices and truncated bases, and thin walled with smooth surface. Dimensions of conidia (n ≥ 50) were (12.8) 15.3 ± 1.4 (17.6) × (5.4) 6.3 ± 0.8 (7.6) μm, with length/width ratio (2.0) 2.5 ± 0.5 (3.2). Based on morphological data, species Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips was suspected (1). For molecular identification, isolates BZ330, SO334, KC342, and PN121 were used for PCR to amplify internal transcribed spacer region and partial translation elongation factor 1-alpha gene, using primers ITS5/ITS4 and EF1-728F/EF1-986R, respectively. Obtained sequences were shown to be identical between the four isolates (GenBank: KF296318, KF296319) and when compared with sequences for reference N. parvum isolate CMW9080 (AY236942, AY236887) they showed >99% homology, confirming the isolates as species N. parvum. Pathogenicity tests were done by inoculation of detached green shoots (GS) and lignified canes (LC) (n = 5) of grapevine cv. Skrlet by either mycelial plugs of the same four isolates, or sterile agar plugs for the controls. Inoculated GS were kept in flasks with sterile water in a glasshouse for 10 days, and LC in humid dark chambers for 30 days, at 25°C. Resulting vascular necrosis measured 62 to 81 mm (GS) and 215 to 246 mm (LC), but was absent on controls. Koch's postulates were satisfied by successful reisolation of N. parvum only from plants inoculated with mycelial plugs. N. parvum has been recognized as a serious grapevine pathogen, causing similar symptoms worldwide (3). To our knowledge, this is the first report of N. parvum associated with GTD in Croatia, and due to its relatively high incidence at surveyed localities, it could present considerable threat, particularly for neighboring vine growing regions. Diplodia seriata De Not., a weak pathogen (3), was also identified from a percentage of samples in this survey. References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) J. Kaliterna et al. Arh. Hig. Rada Toksikol. 63:471, 2012. (3) J. R. Urbez-Torres. Phytopathol. Mediterr. 50(Suppl.):S5, 2011.

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Buzón-Durán, Laura, Natalia Langa-Lomba, Vicente González-García, José Casanova-Gascón, Jesús Martín-Gil, Eduardo Pérez-Lebeña et Pablo Martín-Ramos. « On the Applicability of Chitosan Oligomers-Amino Acid Conjugate Complexes as Eco-Friendly Fungicides against Grapevine Trunk Pathogens ». Agronomy 11, n^o 2 (12 février 2021) : 324. http://dx.doi.org/10.3390/agronomy11020324.

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In a context in which the incidence and severity of grapevine fungal diseases is increasing as a result of both climate change and modern management culture practices, reducing the excessive use of phytosanitary products in viticulture represents a major challenge. Specifically, grapevine trunk diseases (GTDs), caused by several complexes of wood decay or xylem-inhabiting fungi, pose a major challenge to vineyard sustainability. In this study, the efficacy of chitosan oligomers (COS)–amino acid conjugate complexes against three fungal species belonging to the Botryosphaeriaceae family (Neofusicoccum parvum, Diplodia seriata, and Botryosphaeria dothidea) was investigated both in vitro and in planta. In vitro tests led to EC50 and EC90 effective concentrations in the 254.6−448.5 and 672.1−1498.5 µg·mL−1 range, respectively, depending on the amino acid involved in the conjugate complex (viz. cysteine, glycine, proline or tyrosine) and on the pathogen assayed. A synergistic effect between COS and the amino acids was observed against D. seriata and B. dothidea (synergy factors of up to 2.5 and 2.8, respectively, according to Wadley’s method). The formulations based on COS and on the conjugate complex that showed the best inhibition rates, COS−tyrosine, were further investigated in a greenhouse trial on grafted vines of two varieties (”Tempranillo” on 775P and “Garnacha” on 110R rootstock), artificially inoculated with the mentioned three Botryosphaeriaceae species. The in planta bioassay revealed that the chosen formulations induced a significant decrease in disease severity against N. parvum and B. dothidea. In summary, the reported conjugate complexes may be promising enough to be worthy of additional examination in larger field trials.

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Lawrence, Daniel P., Renaud Travadon et Kendra Baumgartner. « Novel Seimatosporium Species from Grapevine in Northern California and Their Interactions with Fungal Pathogens Involved in the Trunk-Disease Complex ». Plant Disease 102, n^o 6 (juin 2018) : 1081–92. http://dx.doi.org/10.1094/pdis-08-17-1247-re.

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Seimatosporium spp. and closely related “pestalotioid fungi” have been isolated from vineyards worldwide, but their ecological status in grapevine wood is unclear. To determine their involvement in the grapevine trunk-disease complex, we tested the pathogenicity of Californian isolates obtained from vines with general symptoms of Botryosphaeria, Eutypa, and Phomopsis diebacks. Multilocus phylogenetic analyses revealed three species: Seimatosporium vitis and two newly described and typified species, S. luteosporum sp. nov. and S. vitifusiforme sp. nov. Inoculations to woody stems of potted grapevines of both isolates of S. vitis and one isolate of S. vitifusiforme, but not S. luteosporum, were associated with significantly larger lesions than those of noninoculated controls. Coinoculations with trunk pathogens (Cryptovalsa ampelina, Diaporthe ambigua, Diatrypella verruciformis, Diplodia seriata, and Eutypa lata), coisolated from the same wood cankers in the field, brought about increased lesion lengths for S. vitifusiforme paired with D. seriata, and S. luteosporum paired with Diaporthe ambigua. In contrast, there were no differences in lesion lengths of S. vitis and Diatrypella verruciformis or S. vitis and E. lata, inoculated alone or together. Our findings suggest that Seimatosporium spp. are involved in the grapevine trunk-disease complex, and their virulence may depend on or affect that of trunk pathogens.

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Reis, Pedro, Ana Gaspar, Artur Alves, Florence Fontaine et Cecília Rego. « Combining an HA + Cu (II) Site-Targeted Copper-Based Product with a Pruning Wound Protection Program to Prevent Infection with Lasiodiplodia spp. in Grapevine ». Plants 10, n^o 11 (4 novembre 2021) : 2376. http://dx.doi.org/10.3390/plants10112376.

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The genus Lasiodiplodia has been reported from several grape growing regions and is considered as one of the fastest wood colonizers, causing Botryosphaeria dieback. The aim of this study was to (i) evaluate the efficacy of Esquive®, a biocontrol agent, on vineyard pruning wound protection, applied single or, in a combined protection strategy with a new site-targeted copper-based treatment (LC2017), and (ii) compare their efficacy with chemical protection provided by the commercially available product, Tessior®. For two seasons, protectants were applied onto pruning wounds, while LC2017 was applied throughout the season according to the manufacturer’s instructions. Pruning wounds of two different cultivars were inoculated with three isolates of Lasiodiplodia spp. Efficacy of the wound protectants, varied between both years of the assay and according to the cultivar studied but were able to control the pathogen to some extent. The application of LC2017 did not show clear evidence of improving the control obtained by the sole application of the other products tested. Nevertheless, LC2017 showed a fungistatic effect against Lasiodiplodia spp., in vitro, and has previously shown an elicitor effect against grapevine trunk diseases. Therefore, this combination of two protection strategies may constitute a promising long-term approach to mitigate the impact of Botryosphaeria dieback.

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Karácsony, Zoltán, Dániel G. Knapp, Szabina Lengyel, Gábor M. Kovács et Kálmán Zoltán Váczy. « The fungus Kalmusia longispora is able to cause vascular necrosis on Vitis vinifera ». PLOS ONE 16, n^o 10 (15 octobre 2021) : e0258043. http://dx.doi.org/10.1371/journal.pone.0258043.

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Fungal diseases in agronomically important plants such as grapevines result in significantly reduced production, pecuniary losses, and increased use of environmentally damaging chemicals. Beside the well-known diseases, there is an increased interest in wood-colonizing fungal pathogens that infect the woody tissues of grapevines. In 2015, a traditional isolation method was performed on grapevine trunks showing symptoms of trunk diseases in Hungary. One isolate (T15142) was identified as Kalmusia longispora (formerly Dendrothyrium longisporum) according to morphological and phylogenetic analyses. To evaluate the pathogenicity of this fungus on grapevines, artificial infections were carried out under greenhouse and field conditions, including the CBS 824.84 and ex-type CBS 582.83 strains. All isolates could be re-isolated from inoculated plants; however, varying virulence was observed among them in terms of the vascular necrosis caused. The incidence and severity of this symptom seemed to be congruent with the laccase-producing capabilities of the isolates. This is the first report on the ability of Kalmusia longispora to cause symptoms on grapevines, and on its possible dependence on laccase secretion.

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Valtaud, Christophe, Christine H. Foyer, Pierrette Fleurat-Lessard et Andrée Bourbouloux. « Systemic effects on leaf glutathione metabolism and defence protein expression caused by esca infection in grapevines ». Functional Plant Biology 36, n^o 3 (2009) : 260. http://dx.doi.org/10.1071/fp08293.

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Esca is a devastating disease of Vitis vinifera L., caused by fungal pathogen(s) inhabiting the wood. The pathogens induce symptoms in the foliage, which are associated with structural and biochemical changes in leaves. The present study was undertaken to examine the effects of the disease on leaf glutathione metabolism in field-grown plants. The glutathione pool decreased and defence proteins such as PR-proteins and chitinases were expressed in the leaves before the appearance of visible symptoms in esca-infected canes. Glutathione depletion was increased as the disease developed in the leaves. The ratio of glutathione disulfide (GSSG) to the total glutathione pool was slightly decreased in leaves without visible symptoms, but it was significantly increased as the disease progressed. The abundance of γ-glutamylcysteine synthetase (γ-ECS) transcripts and of γ-ECS protein was greatly decreased in leaves exhibiting esca symptoms. Although glutathione reductase and glutathione peroxidase transcripts were largely unchanged by the spread of the esca disease, leaf glutathione S-transferase (GST) activities, the amounts of mRNAs encoding GSTU1 and GSTF2 and the abundance of the GSTU1 and GSTF2 proteins were highest at the early stages of infection and then decreased as visible symptoms appeared in the leaves. The GSTF2 protein, which was more abundant than GSTU1, was found in the nucleus and in the cytoplasm, whereas the GSTU1 protein was found largely in the plastids. These data demonstrate that the fungi involved in the esca disease induce pronounced systemic effects in the leaves before the appearance of visible damage. We conclude that the expression of GSTs, the extent of glutathione accumulation and the ratio of GSSG to total glutathione are early indicators of the presence of the esca disease in grapevine canes and thus these parameters can be used as stress markers in field-grown vines.

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Úrbez-Torres, J. R., W. D. Gubler et J. Luque. « First Report of Botryosphaeria iberica and B. viticola Associated with Grapevine Decline in California ». Plant Disease 91, n^o 6 (juin 2007) : 772. http://dx.doi.org/10.1094/pdis-91-6-0772c.

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Grapevine decline symptoms in California include dead spurs and cordon and trunk dieback due to canker formation in the vascular tissue. Seven Botryosphaeria spp. are known to be associated with grapevine cankers in California, viz. Botryosphaeria australis, B. dothidea, B. lutea, B. obtusa, B. parva, B. rhodina, and B. stevensii (3). Recently, B. iberica and B. viticola also were isolated from grapevine cankers in a field survey that was conducted throughout California. Identification was based on morphological comparisons along with DNA analyses with previously identified isolates from Spain (1,2): B. iberica (CBS115035, ex-type) and B. viticola (CBS117006 and CBS117009, ex-type). DNA sequences of the rDNA internal transcribed spacer region (ITSI-5.8S-ITS2), part of the β-tubulin gene (BT2), and part of the translation elongation factor 1-α gene (EF1-α) from B. iberica and B. viticola isolates from California were amplified using primers ITS4/ITS5, Bt2a/Bt2b, and EF-728F/EF-986R, respectively. All DNA sequences of B. iberica and B. viticola from California showed 99 to 100% homology with those previously identified and deposited in GenBank. B. iberica, isolated from grapevine cankers from San Luis Obispo County (central coast), formed colonies on potato dextrose agar (PDA) that were dark green with aerial mycelium, optimum growth at 20 to 25°C, and formed pycnidia after 15 days of incubation at 25°C. Conidia were brown, one-septate, oblong to ovoid with a rounded apex, and measured (20.1-) 22.5 to 23.5 (-27.1) × (8.1) 9.3 to 9.8 (-11.2) μm, length/width ratio = 2.4 (n = 60). B. viticola, isolated from grapevine cankers in Sonoma (north coast), San Luis Obispo, Santa Barbara (south coast), Riverside (southern California), and Yolo (Sacramento Valley) counties, formed colonies on PDA that were dark green to grayish with aerial mycelium, optimum growth at 25°C, and formed pycnidia after 2 weeks. Conidia were brown, one-septate, oval to oblong, and measured (16.6-) 19.3 to 20.3 (-23.5) × (8.1) 9.3 to 9.6 (-11.1) μm, length/width ratio = 2.1 (n = 60). Two isolates of each species were used to complete pathogenicity tests (B. iberica: ATCC MYA-4110, ATCC MYA-4111; B. viticola: ATCC MYA-4115, ATCC MYA-4116). Ten fresh pruning wounds on 15-year-old cv. Zinfandel vines were inoculated per isolate using 50 μl of a 5 × 106 conidia per ml suspension. Twenty control pruning wounds were inoculated with the same amount of sterile water. Twelve months after inoculation, all wood inoculated with B. iberica and B. viticola showed internal necrosis extending 35 to 50 and 30 to 35 mm from the point of inoculation, respectively. Necrosis and extent of vascular discoloration in infected wounds was significantly greater (P < 0.05) than in control inoculations (6.5 mm). B. iberica and B. viticola were reisolated from the necrotic region surrounding all inoculation sites. Representative isolates of B. iberica and B. viticola from California were deposited at the American Type Culture Collection (B. iberica: MYA-4110, MYA-4111; B. viticola: MYA-4112 to MYA-4116). Sequences from the studied DNA regions of all isolates were deposited at GenBank. To our knowledge, this is the first report implicating either species as a cause of grapevine decline in California and B. iberica as a pathogen of Vitis vinifera anywhere in the world. References: (1) J. Luque et al. Mycologia 97:1111, 2005. (2) A. J. L. Phillips et al. Mycologia 97:513, 2005. (3) J. R. Úrbez-Torres et al. Plant Dis. 90:1490, 2006.

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Aroca, A., R. Raposo, D. Gramaje, J. Armengol, S. Martos et J. Luque. « First Report of Lasiodiplodia theobromae Associated with Decline of Grapevine Rootstock Mother Plants in Spain ». Plant Disease 92, n^o 5 (mai 2008) : 832. http://dx.doi.org/10.1094/pdis-92-5-0832b.

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A field of Richter 110 rootstock mother plants in Valencia Province (eastern Spain) was surveyed during November 2006 to study the mycoflora of declining plants. Two canes with stunted leaves were collected from a plant with a reduced number of shoots. No cankers or vascular lesions were observed in the collected canes. Six wood chips (1 to 2 mm thick) were taken from one basal fragment (3 to 4 cm long) of each cane, surface sterilized in 70% ethanol for 1 min, and plated on malt extract agar supplemented with 0.5 g L–1 of streptomycin sulfate. Petri dishes were incubated for 7 days at 25°C. A fungus was consistently isolated from all samples that showed the following characteristics: colonies grown on potato dextrose agar (PDA) at 25°C developed a white, aerial mycelium that turned gray after 4 to 6 days and produced pycnidia after 1 month on sterile grapevine slivers of twigs placed on the PDA surface; conidia from culture were ellipsoidal, thick walled, initially hyaline, nonseptate, and measuring 20 to 25 (22.5) × 12 to 14 (13) μm; aged conidia were brown, 1-septate with longitudinal striations in the wall; and pseudoparaphyses variable in form and length were interspersed within the fertile tissue. The fungus was identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl. from the above characteristics (2). Identity was confirmed by analysis of the nucleotide sequences of the internal transcribed spacer (ITS) region from the rRNA repeat and part of the translation elongation factor 1-alpha (EF1-α) and the β-tubulin (B-tub) genes, as done elsewhere (1,3). BLAST searches at GenBank showed a high identity with reference sequences (ITS: 100%, EF1-α: 97%; B-tub: 99%). Representative sequences of the studied DNA regions were deposited at GenBank (Accession Nos.: ITS: EU254718; EF1-α: EU254719; and B-tub: EU254720). A pathogenicity test was conducted on 1-year-old grapevine plants cv. Macabeo grafted onto Richter 110 rootstocks maintained in a greenhouse. A superficial wound was made on the bark of 10 plants with a sterilized scalpel, ≈10 cm above the graft union. A mycelial plug obtained from the margin of an actively growing fungal colony (isolate JL664) was placed in the wound and the wound was wrapped with Parafilm. Ten additional control plants were inoculated with sterile PDA plugs. All control plants grew normally, and the inoculation wound healed 3 months after inoculation. Plants inoculated with L. theobromae showed no foliar symptoms in the same period, but developed cankers variable in size surrounding the inoculation sites. Vascular necroses measuring 8.4 ± 1.5 cm (mean ± standard error) developed in the inoculated plants that were significantly longer than the controls (0.3 ± 0.2 cm). The pathogen was reisolated from all inoculated plants and no fungus was reisolated from the controls. These results confirmed the pathogenicity of L. theobromae to grapevine and points to a possible involvement of L. theobromae in the aetiology of grapevine decline as previously reported (3,4). To our knowledge, this is the first report of L. theobromae isolated from grapevine in Spain. References: (1) J. Luque et al. Mycologia 97:1111, 2005. (2) E. Punithalingam. No. 519 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1976. (3) J. R. Úrbez-Torres et al. Plant Dis. 90:1490, 2006. (4) J. M. van Niekerk et al. Phytopathol. Mediterr. 45(suppl.):S43, 2006.

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Kanetis, Loukas I., Demetris Taliadoros, Georgios Makris et Michalis Christoforou. « A Novel Seimatosporium and Other Sporocadaceae Species Associated with Grapevine Trunk Diseases in Cyprus ». Plants 11, n^o 20 (16 octobre 2022) : 2733. http://dx.doi.org/10.3390/plants11202733.

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Besides well-known grapevine trunk disease (GTD)-related pathogens, there is an increased interest in wood-colonizing fungi that infect grapevines. During 2017–2018, a survey was conducted in Cyprus and wood samples were collected from vines exhibiting typical GTD symptoms. Based on morphological and multilocus phylogenetic analyses (ITS, LSU, bt2, tef1-a), four species in the Sporocadaceae family were described and typified; two in the genus of Seimatosporium: Seim. cyprium sp. nov. and Seim. vitis-viniferae and two in Sporocadus: Spo. kurdistanicus and Spo. rosigena. The teleomorph of Seim. cyprium sp. nov. was also described. Pathogenicity trials with representative isolates of each species were performed on woody stems of two-year-old potted grapevines for 12 months under field conditions. All isolates were pathogenic, causing dark brown to black vascular discoloration, extending upward and downward from the inoculation point. Sporocadus isolates were significantly more aggressive than Seimatosporium with lesion lengths ranging from 9.24 to 6.90 and 4.13 to 4.00 cm, respectively. Successful re-isolations were also evident for all species and isolates. Seim. cyprium sp. nov. is a newly described species, while Spo. kurdistanicus and Spo. rosigena are reported for the first time in Europe on Vitis vinifera, suggesting the potential role of Sporocadaceae in the GTDs complex

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Dinis, Lia-Tânia, Cláudia Jesus, Joana Amaral, Aurelio Gómez-Cadenas, Barbara Correia, Artur Alves et Glória Pinto. « Water Deficit Timing Differentially Affects Physiological Responses of Grapevines Infected with Lasiodiplodia theobromae ». Plants 11, n^o 15 (28 juillet 2022) : 1961. http://dx.doi.org/10.3390/plants11151961.

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Diseases and climate change are major factors limiting grape productivity and fruit marketability. Lasiodiplodia theobromae is a fungus of the family Botryosphaeriaceae that causes Botryosphaeria dieback of grapevine worldwide. Abiotic stress may change host vitality and impact susceptibility to the pathogen and/or change the pathogen’s life cycle. However, the interaction between both stress drivers is poorly understood for woody plants. We addressed the hypothesis that distinct morpho-physiological and biochemical responses are induced in grapevine (Vitis vinifera)–L. theobromae interactions depending on when water deficits are imposed. Grapevines were submitted to water deficit either before or after fungus inoculation. Water deficit led to the reduction of the net photosynthetic rate, stomatal conductance, and transpiration rate, and increased the abscisic acid concentration regardless of fungal inoculation. L. theobromae inoculation before water deficit reduced plant survival by 50% and resulted in the accumulation of jasmonic acid and reductions in malondialdehyde levels. Conversely, grapevines inoculated after water deficit showed an increase in proline and malondialdehyde content and all plants survived. Overall, grapevines responded differently to the primary stress encountered, with consequences in their physiological responses. This study reinforces the importance of exploring the complex water deficit timing × disease interaction and the underlying physiological responses involved in grapevine performance.

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Úrbez-Torres, J. R., et W. D. Gubler. « Pathogenicity of Botryosphaeriaceae Species Isolated from Grapevine Cankers in California ». Plant Disease 93, n^o 6 (juin 2009) : 584–92. http://dx.doi.org/10.1094/pdis-93-6-0584.

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Fungal species in the family Botryosphaeriaceae have been recently recognized as the most common fungi isolated from grapevine (Vitis vinifera) cankers in California. However, the role of these fungi in causing grapevine dieback as well as their status as canker-causing agents was unknown. Therefore, pathogenicity studies were conducted to determine their importance as grapevine pathogens in California. A total of 72 isolates representing all nine Botryosphaeriaceae species isolated from grapevine cankers from California were used in five different pathogenicity studies. Overall, experiments showed all nine Botryosphaeriaceae species able to infect both young and mature tissues as well as green shoots of the new vegetative growth causing cankers, vascular discoloration, and/or otherwise dark streaking of the wood. However, virulence varied among species. Lasiodiplodia theobromae was the most virulent species followed by Neofusicoccum luteum, N. parvum, and N. australe, all categorized as highly virulent. Botryosphaeria dothidea was considered intermediately virulent and Diplodia mutila, D. seriata, Dothiorella iberica, and D. viticola were shown to be weakly virulent. This study shows species of Botryosphaeriaceae to be much more important pathogens on grapevines than originally thought, and some of them, in view of their virulence, should be considered high risk for causing severe and rapid canker and dieback diseases in the grapevine industry in California.

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Trouillas, F. P., et W. D. Gubler. « Pathogenicity of Diatrypaceae Species in Grapevines in California ». Plant Disease 94, n^o 7 (juillet 2010) : 867–72. http://dx.doi.org/10.1094/pdis-94-7-0867.

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Diatrypaceous fungi have been isolated from cankered wood of grapevines (Vitis vinifera) in California. However, the pathogenicity of these fungi and their potential to cause diseases in grapevine was unknown. A series of pathogenicity tests were conducted to determine if these fungi were grapevine pathogens. In all experiments, species of the family Diatrypaceae were re-isolated from the margins of developing lesions, although frequency of re-isolation and average length of vascular discolorations varied among isolates. Cryptovalsa ampelina, Diatrype stigma, and Eutypa leptoplaca were capable of colonizing dormant canes and causing vascular necrosis. Cryptosphaeria pullmanensis, C. ampelina, D. stigma, Diatrype whitmanensis, and E. leptoplaca infected and caused lesions in green shoots of the new vegetative growth. Diatrype oregonensis and Diatrypella verrucaeformis isolates did not produce lesions that were significantly different from those produced in the control shoots and canes. This suggests that D. oregonensis and D. verrucaeformis fungi may be saprophytic rather than pathogenic to grapevine.

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Lemaitre-Guillier, Christelle, Florence Fontaine, Chloé Roullier-Gall, Mourad Harir, Maryline Magnin-Robert, Christophe Clément, Sophie Trouvelot, Régis D. Gougeon, Philippe Schmitt-Kopplin et Marielle Adrian. « Cultivar- and Wood Area-Dependent Metabolomic Fingerprints of Grapevine Infected by Botryosphaeria Dieback ». Phytopathology® 110, n^o 11 (novembre 2020) : 1821–37. http://dx.doi.org/10.1094/phyto-02-20-0055-r.

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Botryosphaeria dieback is one of the most significant grapevine trunk diseases that affects the sustainability of the vineyards and provokes economic losses. The causal agents, Botryosphaeriaceae species, live in and colonize the wood of the perennial organs causing wood necrosis. Diseased vines show foliar symptoms, chlorosis, or apoplexy, associated to a characteristic brown stripe under the bark. According to the susceptibility of the cultivars, specific proteins such as PR-proteins and other defense-related proteins are accumulated in the brown stripe compared with the healthy woody tissues. In this study, we enhanced the characterization of the brown stripe and the healthy wood by obtaining a metabolite profiling for the three cultivars Chardonnay, Gewurztraminer, and Mourvèdre to deeper understand the interaction between the Botryosphaeria dieback pathogens and grapevine. The study confirmed a specific pattern according to the cultivar and revealed significant differences between the brown stripe and the healthy wood, especially for phytochemical and lipid compounds. This is the first time that such chemical discrimination was made and that lipids were so remarkably highlighted in the interaction of Botryosphaeriaceae species and grapevine. Their role in the disease development is discussed.

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Magnin-Robert, Maryline, Alessandro Spagnolo, Anna Boulanger, Cécile Joyeux, Christophe Clément, Eliane Abou-Mansour et Florence Fontaine. « Changes in Plant Metabolism and Accumulation of Fungal Metabolites in Response to Esca Proper and Apoplexy Expression in the Whole Grapevine ». Phytopathology® 106, n^o 6 (juin 2016) : 541–53. http://dx.doi.org/10.1094/phyto-09-15-0207-r.

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Trunk diseases have become among the most important grapevine diseases worldwide. They are caused by fungal pathogens that attack the permanent woody structure of the vines and cause various symptoms in woody and annual organs. This study examined modifications of plant responses in green stem, cordon, and trunk of grapevines expressing Esca proper (E) or apoplexy (A) event, which are the most frequent grapevine trunk disease symptoms observed in Europe. Transcript expression of a set of plant defense- and stress-related genes was monitored by quantitative reverse-transcription polymerase chain reaction while plant phytoalexins and fungal metabolites were quantified by high-performance liquid chromatography-mass spectrometry in order to characterize the interaction between the grapevine and trunk disease agents. Expression of genes encoding enzymes of the phenylpropanoid pathway and trans-resveratrol content were altered in the three organs of diseased plants, especially in the young tissues of A plants. Pathogenesis-related proteins and the antioxidant system were severely modulated in A plants, which indicates a drastic stress effect. In the meantime, fungal polyketides 6-MSA, (R)-mellein, and (3R,4R)-4-hydroxymellein, were accumulated in A plants, which suggests their potential effect on plant metabolism during the appearance of foliar symptoms.

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Naidu, Rayapati, Adib Rowhani, Marc Fuchs, Deborah Golino et Giovanni P. Martelli. « Grapevine Leafroll : A Complex Viral Disease Affecting a High-Value Fruit Crop ». Plant Disease 98, n^o 9 (septembre 2014) : 1172–85. http://dx.doi.org/10.1094/pdis-08-13-0880-fe.

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Grapevine (Vitis spp.) is one of the most widely grown fruit crops in the world. It is a deciduous woody perennial vine for which the cultivation of domesticated species began approximately 6,000 to 8,000 years ago in the Near East. Grapevines are broadly classified into red- and white-berried cultivars based on their fruit skin color, although yellow, pink, crimson, dark blue, and black-berried cultivars also exist. Grapevines can be subject to attacks by many different pests and pathogens, including graft-transmissible agents such as viruses, viroids, and phytoplasmas. Among the virus and virus-like diseases, grapevine leafroll disease (GLD) is by far the most widespread and economically damaging viral disease of grapevines in many regions around the world. The global expansion of the grape and wine industry has seen a parallel increase in the incidence and economic impact of GLD. Despite the fact that GLD was recognized as a potential threat to grape production for several decades, our knowledge of the nature of the disease is still quite limited due to a variety of challenges related to the complexity of this virus disease, the association of several distinct GLD-associated viruses, and contrasting symptoms in red- and white-berried cultivars. In view of the growing significance of GLD to wine grape production worldwide, this feature article provides an overview of the state of knowledge on the biology and epidemiology of the disease and describes management strategies currently deployed in vineyards.

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Kraus, C., U. Damm, S. Bien, R. T. Voegele et M. Fischer. « New species of Phaeomoniellales from a German vineyard and their potential threat to grapevine (Vitis vinifera) health ». Fungal Systematics and Evolution 6, n^o 1 (15 décembre 2020) : 139–55. http://dx.doi.org/10.3114/fuse.2020.06.08.

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Recently, the order Phaeomoniellales was established that includes fungi closely related to Phaeomoniella chlamydospora, a phytopathogen assumed to be the main causal agent of the two most destructive grapevine trunk diseases, Petri disease and esca. Other species of this order are reported as pathogens of other economically important crops, like olive, peach, apricot, cherry, plum, rambutan, lichee or langsat. However, they are rarely isolated and hence, little is known about their ecological traits and pathogenicity. During a 1-yr period of spore trapping in a German vineyard divided in minimally and intensively pruned grapevines, 23 fungal strains of the Phaeomoniellales were collected. Based on morphological and molecular (ITS, LSU and tub2) analyses the isolated strains were assigned to eight different species. Two species were identified as P. chlamydospora and Neophaeomoniella zymoides, respectively. The remaining six species displayed morphological and molecular differences to known species of the Phaeomoniellales and are newly described, namely Aequabiliella palatina, Minutiella simplex, Moristroma germanicum, Mo. palatinum, Neophaeomoniella constricta and N. ossiformis. A pathogenicity test conducted in the greenhouse revealed that except for P. chlamydospora, none of the species of the Phaeomoniellales isolated from spore traps is able to induce lesions in grapevine wood.

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Yaseen, T., Y. Ahmed, A. M. D'Onghia et M. Digiaro. « First Report of Cylindrocarpon pauciseptatum Associated with Root Rot and Decline of Peach in Southern Italy (Apulia Region) ». Plant Disease 96, n^o 5 (mai 2012) : 764. http://dx.doi.org/10.1094/pdis-10-11-0858.

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During a survey for the sanitary status of stone fruits in southern Italy (Apulia region), symptoms of low vigor, sparse foliage, and chlorosis of leaves, frequently leading to decline or death of the plants, were observed on 3- to 5-year-old peach trees (Prunus persica) cvs. Tardi Belle, Zee Lady, and O'Henry grafted on GF677. Brown-to-black discolorations of the wood were observed in cross-sections of the trunks just below the graft union. Samples were collected from May to June 2010 from two symptomatic orchards in Brindisi and Foggia provinces. Small pieces of brownish, vascular wood and necrotic root tissues were surface disinfested, placed onto potato dextrose agar (PDA), and incubated for 7 days at 25°C in the dark. Single-conidial isolates were subsequently grown on PDA at 25°C for 10 days. Fungal colonies were presumptively identified as members of the genus Cylindrocarpon on the basis of their morphological and conidial characteristics. On PDA, the isolates developed abundant mycelium, which gradually became yellowish or partially brownish. Macroconidia were predominantly three septate, straight and cylindrical with both ends broadly rounded. Chlamydospores and ovoidal microconidia were observed on synthetic nutrient-poor agar (1). Sequence of the ribosomal internal transcribed spacer (ITS) region was obtained using universal primers (ITS6-ITS4) and deposited in GenBank (Accession No. HE577846). This sequence revealed 100% genetic identity with a sequence from Cylindrocarpon pauciseptatum Schroers & Crous (Accession No. EF607090), a recently described species (3). In nature, several species of the genus Cylindrocarpon affect a large number of woody plants, mainly grapevine, olive, and stone fruits, in which they attack the root surface (2). To verify Koch's postulates, the roots of 20 3-month-old peach seedlings (GF305) were dipped for 30 min in a spore suspension of the fungus (1 × 108 conidia ml–1). Seedlings were then transplanted in an artificial soil mix and held under controlled conditions in a greenhouse at 24°C. Typical black-foot symptoms developed on 92% of the inoculated plants within 3 months, whereas the control plants, whose roots had been dipped in distilled water, remained healthy. C. pauciseptatum was reisolated from infected tissues and internal vascular lesions of 45% of the inoculated plants, but none of the plants used as controls, fulfilling Koch's postulates. To our knowledge, this is the first report of this pathogen on peach in the Apulia Region of Italy. Currently, C. pauciseptatum is limited to a few orchards where presumably it was introduced with infected propagating material from extra-regional nurseries. C. pauciseptatum has the potential to negatively affect the stone fruit industry in Italy including reducing nursery production and productivity and vigor of trees in orchards, or even rapid death of young trees. References: (1) W. Gams et al. CBS Course of Mycology. 4th ed. Centraalbureau voor Schimmelcultures, Baarn, the Netherlands, 1998. (2) M. E. S. Hernandez et al. Eur. J. Plant Pathol. 104:347, 1998. (3) H. J. Schroers et al. Mycol. Res. 112:82, 2008.

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