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1
HARDHAM, ADRIENNE R. "Phytophthora cinnamomi." Molecular Plant Pathology 6, no. 6 (November 2005): 589–604. http://dx.doi.org/10.1111/j.1364-3703.2005.00308.x.
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Hardham, Adrienne R., and Leila M. Blackman. "Phytophthora cinnamomi." Molecular Plant Pathology 19, no. 2 (August 22, 2017): 260–85. http://dx.doi.org/10.1111/mpp.12568.
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McDougall, K. L., G. E. St J. Hardy, and R. J. Hobbs. "Additions to the host range of Phytophthora cinnamomi in the jarrah (Eucalyptus marginata) forest of Western Australia." Australian Journal of Botany 49, no. 2 (2001): 193. http://dx.doi.org/10.1071/bt99028.
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Pathogenicity tests with Phytophthora cinnamomi were conducted on 25 perennial species from the jarrah (Eucalyptus marginata) forest of Western Australia. Most species tested had been found in a separate study to be scarce on sites affected by Phytophthora cinnamomi but frequently found in unaffected vegetation. Some species that were known to be field-tolerant of P. cinnamomi and some that were highly susceptible to infection were included in the study for comparison. Phytophthora cinnamomi was recorded from 13 of 17 species not previously known to be susceptible. Phytophthora cinnamomi was subsequently isolated from dead plants of two of these 13 species in the field. The interpretation of results from the glasshouse trials was difficult for some species because of inconsistent patterns of death and P. cinnamomi isolation in the glasshouse trials. Phytophthora cinnamomi probably causes decline in wild populations of Stylidium amoenum, based on the ease of field and glasshouse isolation of P. cinnamomi and the scarcity of this forb on dieback sites. It may also contribute to decline in populations of Boronia fastigiata, Hybanthus floribundus, Labichea punctata, Scaevola calliptera and Stylidium junceum, although further field sampling is required to confirm this.
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Mora-Sala, Beatriz, Mónica Berbegal, and Paloma Abad-Campos. "The Use of qPCR Reveals a High Frequency of Phytophthora quercina in Two Spanish Holm Oak Areas." Forests 9, no. 11 (November 10, 2018): 697. http://dx.doi.org/10.3390/f9110697.
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The struggling Spanish holm oak woodland situation associated with Phytophthora root rot has been studied for a long time. Phytophthora cinnamomi is considered the main, but not the only species responsible for the decline scenario. This study verifies the presence and/or detection of Phytophthora species in two holm oak areas of Spain (southwestern “dehesas” and northeastern woodland) using different isolation and detection approaches. Direct isolation and baiting methods in declining and non-declining holm oak trees revealed Phytophthora cambivora, Phytophthora cinnamomi, Phytophthora gonapodyides, Phytophthora megasperma, and Phytophthora pseudocryptogea in the dehesas, while in the northeastern woodland, no Phytophthora spp. were recovered. Statistical analyses indicated that there was not a significant relationship between the Phytophthora spp. isolation frequency and the disease expression of the holm oak stands in the dehesas. Phytophthora quercina and P. cinnamomi TaqMan real-time PCR probes showed that both P. cinnamomi and P. quercina are involved in the holm oak decline in Spain, but P. quercina was detected in a higher frequency than P. cinnamomi in both studied areas. Thus, this study demonstrates that molecular approaches complement direct isolation techniques in natural and seminatural ecosystem surveys to determine the presence and distribution of Phytophthora spp. This is the first report of P. pseudocryptogea in Europe and its role in the holm oak decline should be further studied.
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Kurzawińska, H., and I. Gajda. "Fungi isolated from soil with quicksets of Chamaecyparis lawsoniana and their influence on the growth of Phytophthora cinnamomi and Rhizoctonia solani." Plant Protection Science 38, SI 2 - 6th Conf EFPP 2002 (December 31, 2017): 631–33. http://dx.doi.org/10.17221/10576-pps.
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Chamaecyparis lawsoniana is often attacked by other pathogens (from genera: Phytophthora, Pythium, Fusarium, Rhizoctonia) both when the quicksets are taken root and later, when the young plants are planted. The aim of the study was to determine an effect of saprobiotic fungi isolated from soil with quicksets Chamaecyparis lawsoniana on the growth of Phytophthora cinnamomi and Rhizoctonia solani. In our experiment, method series biotic was used (MAŃKA 1974). This method allowed to determine index of impendence for plants by Phytophthora cinnamomi and Rhizoctonia solani with the help of summary biotic effect. The results of observation on the biotic interaction of saprobiotic fungi isolated from soil with quicksets Chamaecyparis lawsoniana, analysed as biotic series and Phytophthora cinnamomi and Rhizoctonia solani showed, that this of fungal community did not limited growth of these pathogens. Summary biotic effects were negative. Environment of saprobiotic fungi more promoted growth of Rhizoctonia solani than Phytophthora cinnamomi. It means, that in the soil under Chamaecyparis lawsoniana crop, Rhizoctonia solani could have a better of conditions for growth than Phytophthora cinnamomi.
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McConnell, M. E., and Y. Balci. "Phytophthora cinnamomi as a Contributor to White Oak Decline in Mid-Atlantic United States Forests." Plant Disease 98, no. 3 (March 2014): 319–27. http://dx.doi.org/10.1094/pdis-06-13-0649-re.
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To evaluate Phytophthora cinnamomi as a cause of white oak (Quercus alba) decline in mid-Atlantic forests, sampling was conducted at 102 sites from 2011 to 2012. Soil and roots from healthy and declining white oak trees were collected. Phytophthora spp. were isolated using baiting and CFU of P. cinnamomi quantified using wet-sieving. Fine roots were scanned and measured. Phytophthora spp. were isolated from 43% of the sites. P. cinnamomi was common; six other species were isolated infrequently. Little difference in lesion size existed on white oak seedlings inoculated with 32 isolates of P. cinnamomi; only 13 isolates caused significant mortality. Soils from white oak versus nine other hosts did not have significantly different CFU. P. cinnamomi was restricted to United States Department of Agriculture hardiness zones six and seven and never found in zone five. The presence of Phytophthora spp. in soil can be associated with white oak fine root health. When Phytophthora spp. were present, white oak trees in zones five and six had less fine roots. In mid-Atlantic oak forests, however, environmental conditions appear to play a key role in determining the impact of P. cinnamomi on the root system. P. cinnamomi alone does not appear to be a causal factor of white oak decline.
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Balci, Y., S. Balci, J. Eggers, W. L. MacDonald, J. Juzwik, R. P. Long, and K. W. Gottschalk. "Phytophthora spp. Associated with Forest Soils in Eastern and North-Central U.S. Oak Ecosystems." Plant Disease 91, no. 6 (June 2007): 705–10. http://dx.doi.org/10.1094/pdis-91-6-0705.
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A survey of soils associated with oak species was conducted in 2003 and 2004 in Indiana, Illinois, Maryland, Michigan, Minnesota, Pennsylvania, Ohio, West Virginia, and Wisconsin to investigate the occurrence of Phytophthora spp. Soils taken from around the base of healthy and declining oak trees were flooded with H2O and Quercus robur leaflets were used as bait for Phytophthora spp. From 829 soil samples collected near trees, 21% were positive for Phytophthora spp., with 55% of the 125 sites surveyed yielding a Phytophthora sp. Phytophthora cinnamomi was the most frequently isolated species, representing 69.4% of the Phytophthora-infested sites surveyed. Other species, in decreasing order of isolation frequency were Phytophthora sp. 2, P. citricola, P. europaea, P. cambivora, P. quercina-like isolates, and Phytophthora sp. 1. No significant association was found between the presence of Phytophthora organisms and site characteristics such as latitude, elevation, soil pH, or the crown condition of the trees. However, in P. cinnamomi-infested sites, a significant association was found with the deteriorating crown status of Q. alba and the presence of P. cinnamomi. The absence of P. cinnamomi above the 40°N latitude range also was noteworthy.
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Juhásová, G., and S. Bernadovičová. "Efficacy of biofungicides Supresivit and Polyversum against Phytophthora root pathogens on European chestnut (Castanea sativa Mill.)." Horticultural Science 31, No. 3 (November 25, 2011): 109–14. http://dx.doi.org/10.17221/3802-hortsci.
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The effect of two commercially produced biopreparations on the originators of chestnut ink disease in Slovakia – soil fungi Phytophthora cambivora and Phytophthora cinnamomi was tested in laboratory conditions. Investigations of interrelations between Trichoderma harzianum (Pythium oligandrum) and isolates of Phytophthora sp. obtained from infected tissues of Castanea sativa Mill. proved more important inhibitive effects for Pythium oligandrum (biopreparation Polyversum) efficiency 25.3% (Ph. cambivora) and 26.2% (Ph. cinnamomi). Biopreparation Supresivit (Trichoderma harzianum) reached the efficiency 9.1% for Ph. cambivora isolates and 9.2% for Ph. cinnamomi isolates. Significant effect of the used bioformulas for inhibition of mycelial growth of both Phytophthora sp. and significant difference in the efficacy of two different bioformulas were confirmed statistically.
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Agapito Amador, María Eugenia, Víctor David Cibrián-Llanderal, Mónica Gutiérrez Rojas, Daniel Ruiz-Juárez, Betzabe Ebenhezer López Corona, and Edgar Omar Rueda-Puente. "Phytophthora cinnamomi Rands en aguacate." Revista Mexicana de Ciencias Agrícolas, no. 28 (September 22, 2022): 331–41. http://dx.doi.org/10.29312/remexca.v13i28.3287.
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El objetivo de la presente revisión es dar a conocer el estatus epidemiológico de Phytophthora cinnamomi Rands en interacción con Persea americana Mill. y las alternativas de manejo fitosanitario autorizadas. El ensayo se realizó con base en reportes de instancias oficiales y científicas en materia de sanidad vegetal, de brotes epidemiológicos de la enfermedad tristeza del aguacate causada por P. cinnamomi. A nivel mundial, la pérdida de árboles de aguacate fue exponencial, debido a la enfermedad causada por el oomiceto P. cinnamomi quien presentó comportamiento epidemiológico a nivel nacional e internacional. En 1942, en Puerto Rico el patógeno fue aislado por primera vez por Tucker en plantas de aguacate. En México, el primer brote epidemiológico por este patógeno fue en 1952, con pérdidas de 90% de la producción de aguacate, la distribución de la enfermedad se expandió a diferentes partes del mundo. En condiciones favorables afecta la raíz y base de la corona, invade haces vasculares y toma los nutrientes para su desarrollo. La patogénesis es influenciada por la temperatura, precipitación, humedad, pH, disponibilidad de nutrientes y textura del suelo. En campo, la efectividad biológica de las moléculas, para el control del oomiceto, puede presentar limitantes que impactan en la microbiota, flora y fauna; además, de los efectos que se reflejan en la calidad e inocuidad de frutos por la acumulación de moléculas de plaguicidas sintéticos. Dada la situación fitosanitaria que expresa la producción de aguacate es necesario implementar alternativas de manejo sustentable, como la endoterapia, a través de la inyección de productos selectivos en dosis específicas, que controlen a la enfermedad sin afectar la calidad e inocuidad del fruto.
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Joubert, Melissa, Robert Backer, Juanita Engelbrecht, and Noëlani van den Berg. "Expression of several Phytophthora cinnamomi putative RxLRs provides evidence for virulence roles in avocado." PLOS ONE 16, no. 7 (July 14, 2021): e0254645. http://dx.doi.org/10.1371/journal.pone.0254645.
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Phytophthora cinnamomi is a plant pathogenic oomycete that causes Phytophthora root rot of avocado (PRR). Currently, there is a limited understanding of the molecular interactions underlying this disease. Other Phytophthora species employ an arsenal of effector proteins to manipulate host physiology, of which the RxLR effectors contribute to virulence by interfering with host immune responses. The aim of this study was to identify candidate RxLR effectors in P. cinnamomi that play a role in establishing PRR, and to infer possible functions for these effectors. We identified 61 candidate RxLR genes which were expressed during infection of a susceptible avocado rootstock. Several of these genes were present in multiple copies in the P. cinnamomi genome, suggesting that they may contribute to pathogen fitness. Phylogenetic analysis of the manually predicted RxLR protein sequences revealed 12 P. cinnamomi RxLRs that were related to characterised effectors in other Phytophthora spp., providing clues to their functions in planta. Expression profiles of nine more RxLRs point to possible virulence roles in avocado–highlighting a way forward for studies of this interaction. This study represents the first investigation of the expression of P. cinnamomi RxLR genes during the course of avocado infection, and puts forward a pipeline to pinpoint effector genes with potential as virulence determinants, providing a foundation for the future functional characterization of RxLRs that contribute to P. cinnamomi virulence in avocado.
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Kim, Hyung-Moo, Kyo-Hoon Jin, and Jung-Ae Ko. "Stem Rot of English Ivy Caused by Phytophthora cinnamomi." Research in Plant Disease 13, no. 3 (December 1, 2007): 207–10. http://dx.doi.org/10.5423/rpd.2007.13.3.207.
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Downer, A. J., J. A. Menge, and E. Pond. "Association of Cellulytic Enzyme Activities in Eucalyptus Mulches with Biological Control of Phytophthora cinnamomi." Phytopathology® 91, no. 9 (September 2001): 847–55. http://dx.doi.org/10.1094/phyto.2001.91.9.847.
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A series of samples were taken from mulched and unmulched trees starting at the surface of mulch or soil to a 15 cm soil depth, forming a vertical transect. Saprophytic fungi isolated from the soil samples on rose bengal medium and surveyed visually were most abundant in mulches and at the interface of mulch and soil (P < 0.05). Microbial activity as assayed by the hydrolysis of fluorescein diacetate was significantly greater in mulch layers than in soils. Cellulase and laminarinase enzyme activities were greatest in upper mulch layers and rapidly decreased in soil layers (P < 0.05). Enzyme activities against Phytophthora cinnamomi cell walls were significantly greater in mulch than in soil layers. When Phytophthora cinnamomi was incubated in situ at the various transect depths, it was most frequently lysed at the interface between soil and mulch (P < 0.001). Roots that grew in mulch layers were significantly less infected with Phytophthora cinnamomi than roots formed in soil layers. In mulched soil, roots were commonly formed at the mulch-soil interface where Phytophthora populations were reduced, whereas roots in unmulched soil were numerous at the 7.5 cm depth where Phytophthora cinnamomi was prevalent. Enzyme activities were significantly and positively correlated with each other, microbial activity, and saprophytic fungal populations, but significantly and negatively correlated with Phytophthora recovery.
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Benson, D. M., and Frank A. Blazich. "Control of Phytophthora Root Rot of Rhododendron chapmanii A. Gray with Subdue." Journal of Environmental Horticulture 7, no. 2 (June 1, 1989): 73–75. http://dx.doi.org/10.24266/0738-2898-7.2.73.
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Abstract Rooted cuttings of Chapman's rhododendron (Rhododendron chapmanii) in soilless medium were challenged with inoculum of the soi1borne fungus, Phytophthora cinnamomi (Rands). A portion of the plants received a soil drench of Subdue 2EC (metalaxyl) at 0.16 ml/L (2.0 oz/100 gal) at 2 month intervals. Chapman's rhododendron was highly susceptible to P. cinnamomi, but five of six plants treated with Subdue did not develop symptoms of Phytophthora root rot. In the one plant which developed root rot symptoms, P. cinnamomi was recovered in culture.
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Varghese, Binta, Ravisankar Valsalan, and Deepu Mathew. "Novel MicroRNAs and their Functional Targets from Phytophthora infestans and Phytophthora cinnamomi." Current Genomics 23, no. 1 (January 2022): 41–49. http://dx.doi.org/10.2174/1389202923666211223122305.
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Background: Even though miRNAs play vital roles in developmental biology by regulating the translation of mRNAs, they are poorly studied in oomycetes, especially in the plant pathogen Phytophthora. Objective: The study aimed to predict and identify the putative miRNAs and their targets in Phytophthora infestans and Phytophthora cinnamomi. Methods: The homology-based comparative method was used to identify the unique miRNA sequences in P. infestans and P. cinnamomi with 148,689 EST and TSA sequences of these species. Secondary structure prediction of sRNAs for the 76 resultant sequences has been performed with the MFOLD tool, and their targets were predicted using psRNATarget. Result: Novel miRNAs, miR-8210 and miR-4968, were predicted from P. infestans and P. cinnamomi, respectively, along with their structural features. The newly identified miRNAs were identified to play important roles in gene regulation, with few of their target genes predicted as transcription factors, tumor suppressor genes, stress-responsive genes, DNA repair genes, etc. Conclusion: The miRNAs and their targets identified have opened new interference and editing targets for the development of Phytophthora resistant crop varieties.
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Shearer, BL, BJ Michaelsen, and HJ Warren. "Comparative Behaviour of Phytophthora Species in the Secondary Phloem of Stems and Excised Roots of Banksia grandis and Eucalyptus marginata." Australian Journal of Botany 35, no. 1 (1987): 103. http://dx.doi.org/10.1071/bt9870103.
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We inoculated excised roots under controlled laboratory conditions and inoculated stems in the field to compare the behaviour of Phytophthora cactorum, P. cambivora, P. cinnamomi A2, P. citricola, P. cryptogea A1 and A2, P. megasperma var. sojae and P. nicotianae var. parasitica in the secondary phloem of Banksia grandis and Eucalyptus marginata. Most of the Phytophthora species grew in excised roots of E. marginata at a similar rate. Of the Phytophthora species with similar rates of growth in E. marginata roots, P. cinnamomi was the only species that consistently grew faster in excised roots of B. grandis than in roots of E. marginata. The growth of the Phytophthora species in excised roots under controlled conditions was significantly correlated with growth in intact stems in the field. Over a range of temperatures between 10 and 25°C, the slope of the temperature-growth response curve for P. cinnamomi in excised roots of B. grandis was greater than that for P. citricola. At temperatures between 27 and 31°C, growth rates of P. cinnarnomi in excised roots of B. grandis were 1 cm or more per day compared with 0.3 cm per day for P. citricola. Differences in growth rate in the roots of the widespread understorey species B. grandis can be important to the epidemiology of a Phytophthora species in the E. marginata forest. Phytophthora cinnamomi with fast rates of growth in roots of B. grandis is more likely to have inoculum in the vicinity of major roots of E. marginata than are Phytophthora species with slow rates of growth.
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Horner, I. J., and E. G. Hough. "Pathogenicity of four Phytophthora species on kauri in vitro and glasshouse trials." New Zealand Plant Protection 67 (January 8, 2014): 54–59. http://dx.doi.org/10.30843/nzpp.2014.67.5722.
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In kauri forest soils surveys Phytophthora taxon Agathis (PTA) P cinnamomi P multivora and P cryptogea were detected frequently In vitro and glasshouse studies determined that all four Phytophthora species produced lesions on excised kauri leaves and stems Lesion advance was significantly slower with P cinnamomi P multivora and P cryptogea than with PTA When 2yearold kauri seedlings were trunkinoculated lesion spread was rapid with PTA trunks were girdled and all trees died within 46 weeks Phytophthora cinnamomi P multivora and P cryptogea produced substantially smaller lesions than PTA no trees died and plant growth was only slightly suppressed Following soil inoculation with PTA all kauri seedlings died within 10 weeks There were no deaths following soil inoculation with P cinnamomi P multivora or P cryptogea although feeder root damage was observed and the respective pathogens were reisolated Results suggest that PTA is an aggressive pathogen and the other three species are weaker pathogens of kauri
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Andrade-Hoyos, Petra, Omar Romero-Arenas, Hilda Victoria Silva-Rojas, Alfonso Luna-Cruz, José Espinoza-Pérez, Aarón Mendieta-Moctezuma, and José Alberto Urrieta-Velázquez. "Cinnamom verum Plantations in the Lowland Tropical Forest of Mexico Are Affected by Phytophthora cinnamomi, Phylogenetically Classified into Phytophthora Subclade 7c." Horticulturae 9, no. 2 (February 2, 2023): 187. http://dx.doi.org/10.3390/horticulturae9020187.
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Cinnamon is a tree introduced to the lowlands of Mexico in the mid-16th century, but it spread to other places at the beginning of the 20th century due to its important commercial value as an aromatic spice. In the state of Veracruz, symptoms of dieback have been observed in 12-year-old cinnamon plantations cultivated in an agroforestry system, causing concern among producers. For this reason, the present investigation was carried out to determine the causal agent of these symptoms observed in cinnamon trees. Fifty symptomatic plants were recovered from established plantations. One hundred cinnamon root fragments showing dieback were selected and separated; isolates were made from tissue showing crown and root rot on clarified juice V-8 agar medium. After eight days, the growth of whitish coralloid mycelium with characteristics similar to the Phytophthora oomycete was consistently observed. Subsequently, the identity corresponding to P. cinnamomi was confirmed by morphological, taxonomic studies and Bayesian inference of the rDNA internal transcribed spacer. The pathogenicity test was performed on 20 6-month-old cinnamon plants grown in pots by inoculating 2.5 × 104/mL of zoospores around the roots. Control plants were inoculated with sterile distilled water and kept in a greenhouse under conditions controlled. After five weeks, symptoms of root rot were observed in the inoculated plants; however, the control group plants remained healthy. The results showed that P. cinnamomi subclade 7c was responsible for the symptoms observed in lowland cinnamon plantations in Mexico. Our findings suggest that this phytopathogen is a new threat for cinnamon growers; likewise, it is recommended that growers implement management strategies to avoid its introduction into nurseries or new plantations that could be susceptible to this pathogen.
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Vivas, María, Jerónimo Hernández, Tamara Corcobado, Elena Cubera, and Alejandro Solla. "Transgenerational Induction of Resistance to Phytophthora cinnamomi in Holm Oak." Forests 12, no. 1 (January 18, 2021): 100. http://dx.doi.org/10.3390/f12010100.
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The maternal environment of a tree species can influence the development and resistance of its offspring. Transgenerational induction of resistance is well known in plants but its occurrence in forest tree species has been less reported. Quercus ilex L. (holm oak) is a widespread Mediterranean tree species threatened by the invasive Phytophthora cinnamomi Rands pathogen. The influence of P. cinnamomi on the offspring of infected Q. ilex mother trees has not been studied. This study compared the performance and tolerance to P. cinnamomi of seedlings from non-infected and P. cinnamomi-infected trees. Acorns from Q. ilex trees were collected from five forests. After isolations were conducted in the rhizosphere of several trees, in each forest, three trees were selected as non-infected and three were selected as P. cinnamomi-infected. Forty acorns per tree were weighed and sown under greenhouse conditions, and when plants were aged ~9 months they were challenged with P. cinnamomi. Plant mortality was higher in the offspring of non-infected trees than in the offspring of P. cinnamomi-infected trees (26.2% vs. 21.1%, respectively). Consistently, survival probabilities of seedlings from P. cinnamomi-infected trees were higher than those of seedlings from non-infected trees, particularly in seedlings with reduced growth. Although acorns from healthy Q. ilex trees were heavier than acorns from P. cinnamomi-infected trees, the time to death of inoculated seedlings was not influenced by seed weight. The time to death of seedlings was positively related to belowground mass, particularly to an increased proportion of fine secondary roots. We report transgenerational-induced resistance to P. cinnamomi in Q. ilex triggered by an unknown mechanism independent of acorn mass. Information about the persistence of transgenerational effects in Q. ilex offspring and the influence of these effects on plant fitness is crucial to improve the management and regeneration of this declining species.
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Weiland, Jerry E., Carolyn F. Scagel, Niklaus J. Grünwald, E. Anne Davis, Bryan R. Beck, and Val J. Fieland. "Variation in Disease Severity Caused by Phytophthora cinnamomi, P. plurivora, and Pythium cryptoirregulare on Two Rhododendron Cultivars." Plant Disease 102, no. 12 (December 2018): 2560–70. http://dx.doi.org/10.1094/pdis-04-18-0666-re.
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Rhododendrons are an important crop in the ornamental nursery industry, but are prone to Phytophthora root rot. Phytophthora root rot is a continuing issue on rhododendrons despite decades of research. Several Phytophthora species are known to cause root rot, but most research has focused on P. cinnamomi, and comparative information on pathogenicity is limited for other commonly encountered oomycetes, including Phytophthora plurivora and Pythium cryptoirregulare. In this study, three isolates each of P. cinnamomi, P. plurivora, and Py. cryptoirregulare were used to inoculate rhododendron cultivars Cunningham’s White and Yaku Princess at two different inoculum levels. All three species caused disease, especially at the higher inoculum level. P. cinnamomi and P. plurivora were the most aggressive pathogens, causing severe root rot, whereas Py. cryptoirregulare was a weak pathogen that only caused mild disease. Within each pathogen species, isolate had no influence on disease. Both P. cinnamomi and P. plurivora caused more severe disease on Cunningham’s White than on Yaku Princess, suggesting that the relative resistance and susceptibility among rhododendron cultivars might be similar for both pathogens. Reisolation of P. cinnamomi and P. plurivora was also greater from plants exhibiting aboveground symptoms of wilting and plant death and belowground symptoms of root rot than from those without symptoms. Results show that both P. cinnamomi and P. plurivora, but not Py. cryptoirregulare, are important pathogens causing severe root rot in rhododendron. This study establishes the risks for disease resulting from low and high levels of inoculum for each pathogen. Further research is needed to evaluate longer term risks associated with low inoculum levels on rhododendron health and to explore whether differences among pathogen species affect disease control.
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Hu, Jiahuai, Chuanxue Hong, Erik L. Stromberg, and Gary W. Moorman. "Mefenoxam Sensitivity in Phytophthora cinnamomi Isolates." Plant Disease 94, no. 1 (January 2010): 39–44. http://dx.doi.org/10.1094/pdis-94-1-0039.
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Phytophthora cinnamomi is a destructive root pathogen of numerous woody plant species in the ornamental plant nursery. Sixty-five isolates of P. cinnamomi were evaluated for mefenoxam sensitivity on 20% clarified V8 agar amended with mefenoxam at 0 or 100 μg/ml. In the presence of mefenoxam at 100 μg/ml, eight isolates were intermediately sensitive, with mycelium growth ranging between 11 and 18% of the nonamended control, and 57 isolates were highly sensitive, with little or no mycelium growth. Five intermediately sensitive and five sensitive isolates were chosen to characterize their responses to mefenoxam at 0, 0.1, 1, 10, and 100 μg/ml. For intermediately sensitive isolates, the mefenoxam concentration causing 50% inhibition of mycelium growth (EC50 values) ranged between 0.03 and 0.08 μg/ml; EC50 values for sensitive isolates varied from 0.01 to 0.02 μg/ml. Five intermediately sensitive and seven sensitive isolates were selected further to assess in vivo sensitivity to mefenoxam using Lupinus angustifolius ‘Russell Hybrids’. Lupine seedlings were treated with distilled water or mefenoxam at label rate (Subdue MAXX, 1 fl. oz. of product per 100 gal.) and then, 2 days later, inoculated with a 5-mm-diameter mycelial plug of P. cinnamomi on each cotyledon. Mefenoxam-treated plants averaged more than 96% less disease than water-treated plants. Mefenoxam provided adequate protection of lupines from infection by all 12 isolates regardless of their in vitro levels of sensitivity to mefenoxam. The ability to develop mefenoxam resistance was assessed in P. cinnamomi isolates with different mefenoxam sensitivity by UV mutagenesis and adapting mycelium to increasing concentrations of mefenoxam. Both UV mutagenesis and mycelium adaptation generated isolates with reduced sensitivity to mefenoxam. These isolates, however, did not grow as quickly as their corresponding parent. This study suggests that P. cinnamomi populations from ornamental nurseries in Virginia are sensitive to mefenoxam.
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Dai, Tingting, Xiao Yang, Tao Hu, Zhongyan Li, Yue Xu, and Chenchen Lu. "A Novel LAMP Assay for the Detection of Phytophthora cinnamomi Utilizing a New Target Gene Identified From Genome Sequences." Plant Disease 103, no. 12 (December 2019): 3101–7. http://dx.doi.org/10.1094/pdis-04-19-0781-re.
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Phytophthora cinnamomi is an ecologically and agriculturally significant plant pathogen. Early and accurate detection of P. cinnamomi is paramount to disease prevention and management. In this study, a loop-mediated isothermal amplification (LAMP) assay utilizing a new target gene Pcinn100006 identified from genomic sequence data was developed and evaluated for the detection of P. cinnamomi. This Pcinn100006 LAMP assay was found highly specific to P. cinnamomi. All 10 tested isolates of P. cinnamomi yielded positive results, whereas 50 isolates belonging to 16 other Phytophthora species, Globisporangium ultimum, and 14 fungal species lacked detection. This assay was 10 times more sensitive (100 pg in a 25-µl reaction mixture) than a conventional PCR assay (2 ng in a 50-µl reaction mixture) for detecting the genomic DNA of P. cinnamomi. In addition, it detected P. cinnamomi from artificially inoculated leaves of Cedrus deodara. Moreover, detection rates of P. cinnamomi using environmental DNAs extracted from 13 naturally infested rhizosphere samples were 100% in the Pcinn100006 LAMP assay versus 46% in the conventional PCR assay. Considering its higher accuracy and shorter time span, this Pcinn100006 LAMP assay is a promising diagnostic tool to replace conventional PCR-based and culture-dependent assays for screening of P. cinnamomi in regions at risk of infection or contamination.
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Shearer, BL, and M. Dillon. "Susceptibility of Plant Species in Eucalyptus marginata Forest to Infection by Phytophthora cinnamomi." Australian Journal of Botany 43, no. 1 (1995): 113. http://dx.doi.org/10.1071/bt9950113.
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Estimates of the susceptibility of plant species of Eucalyptus marginata forest to Phytophthora cinnamomi were obtained by determining the frequency of plant death and isolation of the pathogen from plants occurring in disease centres in the forest. Plant species were assessed and sampled in 63 active disease centres and 17 old centres infested with P. cinnamomi in E. marginata forest north of the Preston River, south-westem Australia. Impact of P. cinnamomi was intermediate (scattered deaths) in 46% of active disease centres and high (most susceptible plants dead) in 29% of active centres. Impact in 65% of old disease centres was high. Dicotyledons (Magnoliidae) out-numbered monocotyledons (Liliidae). Just over half of the species were from six Magnoliidae families with the largest number of species from the Papilionaceae and Proteaceae. The greatest number of species within the Liliidae were consistently from Haemodoraceae. Families in which species tended not to die in disease centres were mainly from the Papilionaceae, Proteaceae, Mimosaceae, Myrtaceae, Dilleniaceae, Apiaceae and Goodeniaceae for the Magnoliidae and Cyperaceae and Haemodoraceae for the Liliidae. The species which tended to die frequently in disease centres were mainly from the Magnoliidae families: Papilionaceae, Proteaceae and Epacridaceae; and the Liliidae family Xanthorrhoeaceae, as well as the only species of the Zamiaceae. Phytophthora cinnamomi was isolated from 38 of the 105 species occurring in three or more active disease centres, but from only 17 of the 107 species occurring in old centres. For most species in active disease centres, the frequency of isolation of P. cinnamomi from plants was much less than the frequency of recently dead plants sampled. Isolation from plants was less frequent than from adjacent soil. The pathogen was isolated from plant or soil mainly for species of the Papilionaceae, Proteaceae, Epacridaceae and Dilleniaceae of the Magnoliideae and the Iridaceae and Xanthorrhoeaceae of the Liliidae. Cross tabulation of species by frequency of death and isolation of P. Cinnamomi from plant and soil provided the opportunity to classify the response of plant species to infection by P. cinnamorni.
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Maia, I., C. Medeira, E. Melo, and A. Cravador. "Quercus suber Infected by Phytophthora cinnamomi. Effects at Cellular Level of Cinnamomin on Roots, Stem and Leaves." Microscopy and Microanalysis 14, S3 (September 2008): 146–47. http://dx.doi.org/10.1017/s1431927608089708.
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Phytophthora cinnamomi has been reported to be regularly associated with cork and holm oak decline. This oomycete secretes elicitins, a group of unique highly conserved proteins that can enhance plant defence reactions.
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Hyde, Geoffrey J., Frank Gubler, and Adrienne R. Hardham. "Ultrastructure of zoosporogenesis in Phytophthora cinnamomi." Mycological Research 95, no. 5 (May 1991): 577–91. http://dx.doi.org/10.1016/s0953-7562(09)80072-5.
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Reed, Sharon E., James T. English, and Rose-Marie Muzika. "Phytophthora Species Detected in Two Ozark Forests with Unusual Patterns of White Oak Mortality." Plant Disease 103, no. 1 (January 2019): 102–9. http://dx.doi.org/10.1094/pdis-02-18-0253-re.
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Widespread decline and mortality of white oaks (Quercus alba) occurred in Missouri Ozark forests between 2011 and 2017. Symptoms included rapid crown death with bronzing of leaves, retention of dead leaves, crown dieback and thinning, and loss of large limbs within one year of death. Decline and mortality were associated with hillside drainages and fit descriptions of European oak forests predisposed to decline by pathogenic Phytophthora species. A survey was performed at two locations in 2014 and 2015 to assess the distribution of dead and declining white oaks, and the occurrence and distribution of Phytophthora species. Multiple Phytophthora species were detected, including P. cinnamomi, P. cactorum, P. europaea, and P. pini. P. cinnamomi was the most common and widely distributed species among plots at both locations. The detection of P. cinnamomi at the base of white oaks was not associated with poor crown vigor. However, more quantitative survey techniques are necessary to clearly evaluate this relationship. P. cinnamomi kills fine roots of white and red oaks in North America and has been associated with the decline of white oaks in the United States (Ohio) and other countries. Further studies are needed to determine the importance of P. cinnamomi in oak decline within the Ozark highlands.
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Hardham, A. R., E. Suzaki, and J. L. Perkin. "Monoclonal antibodies to isolate-, species-, and genus-specific components on the surface of zoospores and cysts of the fungus Phytophthora cinnamomi." Canadian Journal of Botany 64, no. 2 (February 1, 1986): 311–21. http://dx.doi.org/10.1139/b86-045.
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Monoclonal antibodies have been raised to components on the surface of glutaraldehyde-fixed zoospores and cysts of an isolate of the pathogenic fungus Phytophthora cinnamomi. Hybridoma supernatants were screened using an immunofluorescence assay, and of 35 cell lines producing antibodies that reacted with the P. cinnamomi cells, 10 have been selected and their specificities examined in detail. The monoclonal antibodies were found to possess a valuable spectrum of taxonomic specificities, and have revealed, for the first time, the presence of isolate-specific antigens on the surface of P. cinnamomi cells. The monoclonal antibodies were tested against six isolates of P. cinnamomi, six species of Phytophthora, and three species of Pythium. In addition to the isolate-specific monoclonal antibodies, species-specific and genus-specific markers which are unambiguous in tests conducted so far have been obtained. The monoclonal antibodies have also revealed the presence of spatially restricted antigens on the surface of the zoospores. Some of these segregated antigens are species-specific and others are more general, occurring in all Phytophthora and Pythium species examined. All of the monoclonal antibodies promise to be of great assistance in investigations of the biology and taxonomy of P. cinnamomi. The methods described should be readily applicable to studies of other fungal pathogens.
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Varfolomeeva, E. A., and E. O. Rezanko. "Methods of supporting the development of Phytophthora cinnamomi rands on representatives of the Ericaceae DC family. In the orangeries of the Botanical garden of Peter the Great." Plant Biology and Horticulture: theory, innovation 1, no. 157 (January 11, 2021): 26–33. http://dx.doi.org/10.36305/2712-7788-2020-4-157-26-33.
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In recent years, in the orangeries of the Peter the Great Botanical Garden, the affection of representatives of the Ericaceae family, the genus rhododendron (Rhododendron (L.) oomycete Phytophthora cinnamomi, has been growing. In the study of the rhizospheric soil of sick and healthy plants, a wide distribution of Phytophthora was found. representatives of this family. The dynamics of the spread of the disease from 2012 to 2019 is presented. The population of Phytophthora cinnamomi in the soils is unevenly distributed, changing its structure (abundance, survival, seasonality, life cycle) in accordance with various micro -phytocenoses. The population structure is governed by coenotic relationships with soil microorganisms. The Phytophthora cinnamomi population is “pulsating,” with a maximum population (in May-June) and a minimum in NovemberDecember. The creation of suppressive soils and suppression factors may serve as a preliminary strategy when creating measures to protect plants of the Peter the Great Botanical Garden. The results of studies of the effects of biological products (Vitaplan, Sternifag, Gliokladin) and fertilizers (Potassium humate, Ecofus) on the pathogen are presented. To increase immunity, resistance inducers (immunocytophyte, sillplant, chitosan) were used.
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Gastañadui, Paul, Rocío Moreno, Patricia Elena Quiroz-Delgado, and Walter Eduardo Apaza-Tapia. "Control of avocado root rot caused by Phytophthora cinnamomi with different Trichoderma strains at Chavimochic Irrigation Project." Peruvian Journal of Agronomy 5, no. 3 (December 30, 2021): 78–86. http://dx.doi.org/10.21704/pja.v5i3.1846.
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Avocado root rot caused by Phytophthora cinnamomi is one of the main problems affecting avocado (Persea americana) cultivation in Peru, especially at the Chavimochic Irrigation Project. The objective of this study was to evaluate the effect of different Trichoderma strains on the control of Phytophthora cinnamomi in Zutano rootstock under greenhouse conditions. Five isolates of Trichoderma were tested: Trichoderma sp. (Chav01); Trichoderma harzianum (Chavo2); Trichoderma harzianum (UNALM01); Trichoderma viride (UNALM02); and a commercial strain of Trichoderma sp. Evaluations were performed at 30, 45, and 60 days. All isolates colonized the rhizosphere of the avocado. No relation was found between the formation of more Trichoderma colonies and Phytophthora improved control. All strains controlled the root rot, but Chav01 and Chav02 showed the greatest diameter of stem, dry matter in the root, and percentage of healthy root in comparison with UNALM01, UNALM02, and the commercial strain. Thus, the native isolates of Trichoderma from the Chavimochic area can be added to the list of potential new Trichoderma species to control Phytophthora cinnamomi.
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Saiz-Fernández, Iñigo, Ivan Milenković, Miroslav Berka, Martin Černý, Michal Tomšovský, Břetislav Brzobohatý, and Pavel Kerchev. "Integrated Proteomic and Metabolomic Profiling of Phytophthora cinnamomi Attack on Sweet Chestnut (Castanea sativa) Reveals Distinct Molecular Reprogramming Proximal to the Infection Site and Away from It." International Journal of Molecular Sciences 21, no. 22 (November 12, 2020): 8525. http://dx.doi.org/10.3390/ijms21228525.
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Phytophthora cinnamomi is one of the most invasive tree pathogens that devastates wild and cultivated forests. Due to its wide host range, knowledge of the infection process at the molecular level is lacking for most of its tree hosts. To expand the repertoire of studied Phytophthora–woody plant interactions and identify molecular mechanisms that can facilitate discovery of novel ways to control its spread and damaging effects, we focused on the interaction between P. cinnamomi and sweet chestnut (Castanea sativa), an economically important tree for the wood processing industry. By using a combination of proteomics, metabolomics, and targeted hormonal analysis, we mapped the effects of P. cinnamomi attack on stem tissues immediately bordering the infection site and away from it. P. cinnamomi led to a massive reprogramming of the chestnut proteome and accumulation of the stress-related hormones salicylic acid (SA) and jasmonic acid (JA), indicating that stem inoculation can be used as an easily accessible model system to identify novel molecular players in P. cinnamomi pathogenicity.
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Akıllı Şimşek, Seçil, Yakup Zekai Katırcıoğlu, and Salih Maden. "Türkiye’de Orman, Park ve Fidanlıklarda Görülen Phytophthora Kök Çürüklüğü Hastalıkları ve Korunma Önlemleri." Turkish Journal of Agriculture - Food Science and Technology 6, no. 6 (June 26, 2018): 770. http://dx.doi.org/10.24925/turjaf.v6i6.770-782.1928.
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Phytophthora species, as a member of Oomycetes are important plan diseases occurring on almost all of the annual and perennial plants and rapidly killing the plants by producing root, collar rots and leaf blights. The first Phytophthora study on forest trees in Turkey was made on oak species which is the most widespread tree in the country. Seven Phytophthora species, namely P. cinnamomi, P. citricola, P. cryptogea, P. gonapodyides, P. quercina, Phytophthora sp. 1 and Phytophthora sp. 2’ were found to cause dieback and death on oaks, P. quercina being the most frequently encountered. The second most common tree having Phytophthora infections is sweet chestnut and root rots caused by Phytophthora were determined everywhere chestnut grow in the country. Four species were found on chestnut and the most frequently occurring two species are P. cambivora and P. cinnamomi occurring in the inner part and in the coastal areas of the country respectively. The third and fourth species, P. plurivora and P. cryptogea were observed in the decreasing order respectively. From the above mentioned species, P. cambivora and P. cryptogea were also reported from black pine at one location in the newly reforested location. From the other forest trees; various Phytophthora species were reported; P. lacustris from narrow leaved ash, P. plurivora, P. occultans from boxwood, P. citrophthora and P. cactorum from horse chestnut, P. nicotianae from Ailanthus sp. Phytophthora diseases were also found in a few nurseries growing forest an ornamental trees. P. cinnamomi, P. cryptogea, P. cactorum, P. citricola, P. megasperma and P. syringae were found to cause disease on various forest tree saplings. Elaborate information on Phytophthora diseases is being given in the review.
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Ferraris, L., F. Cardinale, D. Valentino, P. Roggero, and G. Tamietti. "Immunological Discrimination of Phytophthora cinnamomi from other Phytophthorae Pathogenic on Chestnut." Journal of Phytopathology 152, no. 4 (April 2004): 193–99. http://dx.doi.org/10.1111/j.1439-0434.2004.00823.x.
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Linde, C., A. Drenth, G. H. J. Kemp, M. J. Wingfield, and S. L. von Broembsen. "Population Structure of Phytophthora cinnamomi in South Africa." Phytopathology® 87, no. 8 (August 1997): 822–27. http://dx.doi.org/10.1094/phyto.1997.87.8.822.
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Phytophthora cinnamomi isolates collected from 1977 to 1986 and 1991 to 1993 in two regions in South Africa were analyzed using isozymes. A total of 135 isolates was analyzed for 14 enzymes representing 20 putative loci, of which four were polymorphic. This led to the identification of nine different multilocus isozyme genotypes. Both mating types of P. cinnamomi occurred commonly in the Cape region, whereas, predominantly, the A2 mating type occurred in the Mpumalanga region of South Africa. A2 mating type isolates could be resolved into seven multilocus isozyme genotypes, compared with only two multilocus isozyme genotypes for the A1 mating type isolates. Low levels of gene (0.115) and genotypic (2.4%) diversity and a low number of alleles per locus (1.43) were observed for the South African P. cinnamomi population. The genetic distance between the Cape and Mpumalanga P. cinnamomi populations was relatively low (Dm = 0.165), and no specific pattern in regional distribution of multilocus isozyme genotypes could be observed. The genetic distance between the “old” (isolated between 1977 and 1986) and “new” (isolated between 1991 and 1993) P. cinnamomi populations from the Cape was low (Dm = 0.164), indicating a stable population over time. Three of the nine multilocus isozyme genotypes were specific to the “old” population, and only one multilocus isozyme genotype was specific to the “new” population. Significant differences in allele frequencies, a high genetic distance (Dm = 0.581) between the Cape A1 and A2 mating type isolates, significant deviations from Hardy-Weinberg equilibrium, a low overall level of heterozygosity, and a high fixation index (0.71) all indicate that sexual reproduction occurs rarely, if at all, in the South African P. cinnamomi population.
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Longmuir, Amy L., Peter L. Beech, and Mark F. Richardson. "Draft genomes of two Australian strains of the plant pathogen, Phytophthora cinnamomi." F1000Research 6 (November 8, 2017): 1972. http://dx.doi.org/10.12688/f1000research.12867.1.
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Background: The oomycete plant pathogen, Phytophthora cinnamomi, is responsible for the destruction of thousands of species of native Australian plants, as well as several crops, such as avocado and macadamia, and has one of the widest host-plant ranges of the Phytophthora genus. The currently available genome of P. cinnamomi is based on an atypical strain and has large gaps in its assembly. To further studies of the pathogenicity of this species, especially in Australia, more robust assemblies of the genomes of more typical strains are required. Here we report the genome sequencing, draft assembly, and preliminary annotation of two geographically separated Australian strains of P. cinnamomi. Findings: Some 308 million raw reads were generated for the two strains. Independent genome assembly produced final genomes of 62.8 Mb (in 14,268 scaffolds) and 68.1 Mb (in 10,084 scaffolds), which are comparable in size and contiguity to other Phytophthora genomes. Gene prediction yielded > 22,000 predicted protein-encoding genes within each genome, while BUSCO assessment showed 82.5% and 81.8% of the eukaryote universal single-copy orthologs to be present in the assembled genomes, respectively. Conclusions: The assembled genomes of two geographically distant isolates of Phytophthora cinnamomi will provide a valuable resource for further comparative analysis and evolutionary studies of this destructive pathogen, and further annotation of the presented genomes may yield possible targets for novel pathogen control methods.
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Longmuir, Amy L., Peter L. Beech, and Mark F. Richardson. "Draft genomes of two Australian strains of the plant pathogen, Phytophthora cinnamomi." F1000Research 6 (February 28, 2018): 1972. http://dx.doi.org/10.12688/f1000research.12867.2.
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Background: The oomycete plant pathogen, Phytophthora cinnamomi, is responsible for the destruction of thousands of species of native Australian plants, as well as several crops, such as avocado and macadamia, and has one of the widest host-plant ranges of the Phytophthora genus. The current reference genome of P. cinnamomi is based on an atypical strain and has large gaps in its assembly. To further studies of the pathogenicity of this species, especially in Australia, robust genome assemblies of more typical strains are required. Here we report the genome sequencing, draft assembly, and preliminary annotation of two geographically separated Australian strains of P. cinnamomi. Findings: Some 308 million raw reads were generated for the two strains, DU054 and WA94.26. Independent genome assembly produced final genome sequences of 62.8 Mb (in 14,268 scaffolds) and 68.1 Mb (in 10,084 scaffolds), which are comparable in size and contiguity to other Phytophthora genomes. Gene prediction yielded > 22,000 predicted protein-encoding genes within each genome, while BUSCO assessment showed 94.4% and 91.5% of the stramenopile single-copy orthologs to be present in the assembled genomes, respectively. Conclusions: The assembled genomes of two geographically distant isolates of Phytophthora cinnamomi will provide a valuable resource for further comparative analyses and evolutionary studies of this destructive pathogen, and further annotation of the presented genomes may yield possible targets for novel pathogen control methods.
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Meadows, I. M., D. C. Zwart, S. N. Jeffers, T. A. Waldrop, and W. C. Bridges. "Effects of Fuel Reduction Treatments on Incidence of Phytophthora Species in Soil of a Southern Appalachian Mountain Forest." Plant Disease 95, no. 7 (July 2011): 811–20. http://dx.doi.org/10.1094/pdis-07-10-0505.
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The National Fire and Fire Surrogate Study was initiated to study the effects of fuel reduction treatments on forest ecosystems. Four fuel reduction treatments were applied to three sites in a southern Appalachian Mountain forest in western North Carolina: prescribed burning, mechanical fuel reduction, mechanical fuel reduction followed by prescribed burning, and a nontreated control. To determine the effects of fuel reduction treatments on Phytophthora spp. in soil, incidences were assessed once before and twice after fuel reduction treatments were applied. Also, the efficiency of the baiting bioassay used to detect species of Phytophthora was evaluated, and the potential virulence of isolates of Phytophthora spp. collected from forest soils was determined. Phytophthora cinnamomi and P. heveae were the only two species recovered from the study site. Incidences of these species were not significantly affected by fuel reduction treatments, but incidence of P. cinnamomi increased over time. In the baiting bioassay, camellia leaf disks were better than hemlock needles as baits. P. cinnamomi was detected best in fresh soil, whereas P. heveae was detected best when soil was air-dried and remoistened prior to baiting. Isolates of P. heveae were weakly virulent and, therefore, potentially pathogenic—causing lesions only on wounded mountain laurel and rhododendron leaves; however, isolates of P. cinnamomi were virulent and caused root rot and mortality on mountain laurel and white pine plants.
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Kunadiya, Manisha B., William D. Dunstan, Diane White, Giles E. St J. Hardy, Andrew H. Grigg, and Treena I. Burgess. "A qPCR Assay for the Detection of Phytophthora cinnamomi Including an mRNA Protocol Designed to Establish Propagule Viability in Environmental Samples." Plant Disease 103, no. 9 (September 2019): 2443–50. http://dx.doi.org/10.1094/pdis-09-18-1641-re.
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Phytophthora cinnamomi causes root and collar rot in many plant species in natural ecosystems and horticulture. A species-specific primer and probe PCIN5 were designed based on a mitochondrial locus encoding subunit 2 of cytochrome c oxidase (cox2). Eight PCR primers, including three forward and five reverse, were designed and tested in all possible combinations. Annealing temperatures were optimized for each primer pair set to maximize both specificity and sensitivity. Each set was tested against P. cinnamomi and two closely related clade 7 species, P. parvispora and P. niederhauseri. From these tests, five primer pairs were selected based on specificity and, with a species-specific P. cinnamomi probe, used to develop quantitative real-time PCR (qPCR) assays. The specificity of the two most sensitive qPCR assays was confirmed using the genomic DNA of 29 Phytophthora isolates, including 17 isolates of 11 species from clade 7, and representative species from nine other clades (all except clade 3). The assay was able to detect as little as 150 ag of P. cinnamomi DNA and showed no cross-reaction with other Phytophthora species, except for P. parvispora, a very closely related species to P. cinnamomi, which showed late amplification at high DNA concentrations. The efficiency of the qPCR protocol was evaluated with environmental samples including roots and associated soil from plants artificially infected with P. cinnamomi. Different RNA isolation kits were tested and evaluated for their performance in the isolation of RNA from environmental samples, followed by cDNA synthesis, and qPCR assay. Finally, a protocol was recommended for determining the presence of P. cinnamomi in recalcitrant environmental samples.
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Nagle, Annemarie M., Robert P. Long, Laurence V. Madden, and Pierluigi Bonello. "Association of Phytophthora cinnamomi with White Oak Decline in Southern Ohio." Plant Disease 94, no. 8 (August 2010): 1026–34. http://dx.doi.org/10.1094/pdis-94-8-1026.
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A decline syndrome and widespread mortality of mature white oak tree (Quercus alba) associated with wet and low-lying areas has been recently observed in southern Ohio forests. Previous studies have isolated Phytophthora cinnamomi from white oak rhizospheres. In 2008 and 2009, P. cinnamomi population densities in two healthy and two declining white oak stands at Scioto Trail State Forest were quantified and potential roles of three environmental drivers of Phytophthora spp.–induced decline were assessed: soil texture, soil moisture, and topography. Significantly higher P. cinnamomi propagule densities were found in declining stands in both years but propagule densities were not associated with soil moisture content. Trends in population densities were not correlated with soil moisture or topographic position within field sites. There was a positive, exponential relationship between overall P. cinnamomi population levels and soil moisture on a seasonal scale in 2008 but not 2009. Sites with greater soil clay content were associated with greater decline. Effects of P. cinnamomi inoculum and periodic flooding on root health of 1-year-old potted white oak trees grown in native soil mixes in the greenhouse were examined. Root systems of potted oak were significantly damaged by soil inoculation with P. cinnamomi, especially under flooding conditions. Results of these studies support the hypothesis that P. cinnamomi is a contributing agent to white oak decline in southern Ohio.
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Bregant, Carlo, Antonio A. Mulas, Giovanni Rossetto, Antonio Deidda, Lucia Maddau, Giovanni Piras, and Benedetto T. Linaldeddu. "Phytophthora mediterranea sp. nov., a New Species Closely Related to Phytophthora cinnamomi from Nursery Plants of Myrtus communis in Italy." Forests 12, no. 6 (May 27, 2021): 682. http://dx.doi.org/10.3390/f12060682.
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Monitoring surveys of Phytophthora related diseases in four forest nurseries in Italy revealed the occurrence of fourteen Phytophthora species to be associated with collar and root rot on fourteen plants typical of Mediterranean and alpine regions. In addition, a multilocus phylogeny analysis based on nuclear ITS and ß-tubulin and mitochondrial cox1 sequences, as well as micromorphological features, supported the description of a new species belonging to the phylogenetic clade 7c, Phytophthora mediterranea sp. nov. Phytophthora mediterranea was shown to be associated with collar and root rot symptoms on myrtle seedlings. Phylogenetically, P. mediterranea is closely related to P. cinnamomi but the two species differ in 87 nucleotides in the three studied DNA regions. Morphologically P. mediterranea can be easily distinguished from P. cinnamomi on the basis of its smaller sporangia, colony growth pattern and higher optimum and maximum temperature values. Data from the pathogenicity test showed that P. mediterranea has the potential to threaten the native Mediterranean maquis vegetation. Finally, the discovery of P. cinnamomi in alpine nurseries, confirms the progressive expansion of this species towards cold environments, probably driven by climate change.
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Keast, D., C. Tonkin, and L. Sanfelieu. "Effects of Copper Salts on Growth and Survival of Phytophthora cinnamomi in vitro and on the Antifungal Activity of Actinomycete Populations From the Roots of Eucalyptus marginata and Banksia grandis." Australian Journal of Botany 33, no. 2 (1985): 115. http://dx.doi.org/10.1071/bt9850115.
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Seven copper salts and 10 isolates from both mating types of Phytophthora cinnamomi have been tested, in vitro, for copper cation toxicity to mycelial mat growth and to the germination of chlamydospores. It has been shown that while the copper ion is toxic, extended periods of exposure (9-23 days) to the cation are often required to change the fungistatic activity to that of a true fungicide. This observation applies to both mycelial growth and to chlamydospore germination of P. cinnamomi. Soluble copper (CuS02.5H20) gave short-term protection of both Eucalyptus marginata and to a lesser degree Banksia grandis against infection by P. cinnamomi but insoluble copper (CuO) gave none. The rhizospheres of seedlings of E. marginata and B. grandis grown in pots contained populations of soil actinomycetes different from each other and the parent soil population. These actinomycetes showed substantial antifungal activity against Phytophthora cinnamomi in vitro. Moreover, the actinomycete populations were modified by the presence of copper and by the infection of the roots by P. cinnamomi. It is suggested that both the actinomycetes and the copper contributed to the protection against invasion by P. cinnamomi.
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Duncan, MJ, and PJ Keane. "Vegetation Changes Associated With Phytophthora cinnamomi and Its Decline Under Xanthorrhoea australis in Kinglake National Park, Victoria." Australian Journal of Botany 44, no. 3 (1996): 355. http://dx.doi.org/10.1071/bt9960355.
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Changes in the species composition associated with the presence of Phytophthora cinnamomi Rands and changes in the potential activity of the fungus were measured at a dry sclerophyll forest site in Kinglake National Park. In soil infested with P. cinnamomi, both the percentage cover and density of the major overstorey species (Eucalyptus dives Schauer in Walp. and E. macrorhyncha F.Muell.) and major understorey species (Xanthorrhoea australis R.Br., Daviesia ulicifolia Andrews and Dillwynia phylicoides Cunn.) were significantly reduced, while both the cover and density of the sedge species (Gahnia sieberiana Kunth., Lepidosperma laterale R.Br.and L. semiteres F.Muell.) increased significantly. The density of the major grass species, Chionochloa pallida (R.Br.) S. W. L.Jacobs, did not change. Species that were susceptible to P. cinnamomi showed varying patterns of decline. Xanthorrhoea australis was the most sensitive to the presence of P. cinnamomi, showing an immediate and large decline in both percentage cover and density, while Daviesia ulicifolia was the least sensitive, showing a decline only at later stages of disease development in the vegetation. Lepidosperma laterale and L. seiiziteres were the major colonisers of the diseased vegetation at this site, and were succeeded by Gahnia sieberiana, which became the dominant sedge species in the diseased zone after the dead plants of X. australis had collapsed. A seasonal survey (1992-1994) of P. cinnamomi found the pathogen to be potentially active all year round at this site, with summer and winter maxima. A decline was measured in the potential activity of P. cinnamorni underneath diseased and dead plants of X. australis after a disease outbreak. The potential activity of P. cinnamomi was greatest in soil collected from the base of dying plants of X. australis and zero in soil from under dead and collapsed individuals of that species. A similar pattern of decline in the potential pathogen activity was measured for the same host species at disease sites in the Brisbane Ranges National Park and Angahook State Park. A similar consistent pattern of decline in the disease potential of P. cinnamomi in soil from under diseased and dead plants of X. australis was observed in a pot bioassay. This decline in disease potential was overcome by the addition of Eucalyptus sieberi L.A.S.Johnson seedlings and P. cinnamomi inoculum to the soil.
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Toapanta Gallegos, Diana Elizabeth. "Diagnóstico molecular de Phytophthora cinnamomi asociado a la pudrición radicular en zonas productoras de aguacate en Ecuador." Corpoica Ciencia y Tecnología Agropecuaria 18, no. 2 (May 8, 2017): 285. http://dx.doi.org/10.21930/rcta.vol18_num2_art:628.
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<p>Phytophthora cinnamomi Rands está asociado<br />con la pudrición radicular, una de las enfermedades<br />más importantes en el cultivo de aguacate<br />(Persea americana Mill.) debido a que ocasiona<br />marchitez progresiva hasta provocar la muerte del<br />árbol. El objetivo de este estudio fue identificar<br />molecularmente la presencia de P. cinnamomi con<br />la técnica PCR-RFLP, en plantaciones de aguacate<br />en dos zonas productoras del Ecuador. Con este<br />fin, se obtuvieron muestras de raíces de árboles con<br />sintomatología de pudrición radicular en las zonas<br />Palabras clave: aislamiento, Ecuador, Persea americana, Phytophthora cinnamomi<br />de producción. A partir de estas se obtuvieron diez<br />aislamientos donde se identificó morfológicamente<br />a Phytophthora sp. Para la distinción de especies<br />de Phytophthora se realizó un análisis molecular<br />con marcadores en la región ITS de ADN ribosomal<br />(ADNr). La digestión del fragmento ITS obtenido<br />por PCR con la enzima TaqI permitió confirmar la<br />presencia de P. cinnamomi en los aislamientos y,<br />por lo tanto, asociar su presencia con la pudrición<br />radicular en las zonas de producción muestreadas.</p>
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Alvarado, Laureano, Sebastián Saa, Italo F. Cuneo, Romina Pedreschi, Javiera Morales, Alejandra Larach, Wilson Barros, Jeannette Guajardo, and Ximena Besoain. "A Comparison of Immediate and Short-Term Defensive Responses to Phytophthora Species Infection in Both Susceptible and Resistant Walnut Rootstocks." Plant Disease 104, no. 3 (March 2020): 921–29. http://dx.doi.org/10.1094/pdis-03-19-0455-re.
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Clonal rootstocks are one alternative used by the walnut industry to control damage caused by Phytophthora species, traditionally using plants grafted on susceptible Juglans regia rootstock. Vlach, VX211, and RX1 are clonal rootstocks with a degree of resistance to Phytophthora species. The resistance to pathogens in these rootstocks depends on the resistance mechanisms activated by the presence of the pathogen and subsequent development of responses in the host. In this work, we analyzed how plants of J. regia, Vlach, VX211, and RX1 responded to inoculation with Phytophthora cinnamomi or Phytophthora citrophthora isolates obtained from diseased English walnut plants from Chilean orchards. After inoculation, plants of Vlach, VX211, and RX1 showed canopy and root damage indexes that did not differ from noninoculated control plants. In contrast, plants of J. regia, which is susceptible to P. cinnamomi and P. citrophthora, died after inoculation. Vlach, VX211, and RX1 plants inoculated with P. cinnamomi or P. citrophthora showed greater root weight and volume and greater root growth rates than their respective controls. These results suggest that short-term carbohydrate dynamics may be related to the defense mechanisms of plants; they are immediately activated after inoculation through the production of phenolic compounds, which support the further growth and development of roots in walnut clonal rootstocks. To our knowledge, this is the first study that comprehensively characterizes vegetative and radicular growth and the dynamics of sugars and phenols in response to infection with P. cinnamomi or P. citrophthora in walnut rootstocks.
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Khdiar, Mohammed Y., Paul A. Barber, Giles E. StJ Hardy, Chris Shaw, Emma J. Steel, Cameron McMains, and Treena I. Burgess. "Association of Phytophthora with Declining Vegetation in an Urban Forest Environment." Microorganisms 8, no. 7 (June 29, 2020): 973. http://dx.doi.org/10.3390/microorganisms8070973.
Full textAbstract:
Urban forests consist of various environments from intensely managed spaces to conservation areas and are often reservoirs of a diverse range of invasive pathogens due to their introduction through the nursery trade. Pathogens are likely to persist because the urban forest contains a mixture of native and exotic plant species, and the environmental conditions are often less than ideal for the trees. To test the impact of different land management approaches on the Phytophthora community, 236 discrete soil and root samples were collected from declining trees in 91 parks and nature reserves in Joondalup, Western Australia (WA). Sampling targeted an extensive variety of declining native trees and shrubs, from families known to be susceptible to Phytophthora. A sub-sample was set aside and DNA extracted for metabarcoding using Phytophthora-specific primers; the remaining soil and root sample was baited for the isolation of Phytophthora. We considered the effect on the Phytophthora community of park class and area, soil family, and the change in canopy cover or health as determined through sequential measurements using remote sensing. Of the 236 samples, baiting techniques detected Phytophthora species from 24 samples (18 parks), while metabarcoding detected Phytophthora from 168 samples (64 parks). Overall, forty-four Phytophthora phylotypes were detected. Considering only sampling sites where Phytophthora was detected, species richness averaged 5.82 (range 1–21) for samples and 9.23 (range 2–24) for parks. Phytophthora multivora was the most frequently found species followed by P. arenaria, P. amnicola and P. cinnamomi. While park area and canopy cover had a significant effect on Phytophthora community the R2 values were very low, indicating they have had little effect in shaping the community. Phytophthora cinnamomi and P. multivora, the two most invasive species, often co-occurring (61% of samples); however, the communities with P. multivora were more common than those with P. cinnamomi, reflecting observations over the past decade of the increasing importance of P. multivora as a pathogen in the urban environment.
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Medeira, C., I. Maia, C. Ribeiro, I. Candeias, E. Melo, N. Sousa, and A. Cravador. "ALPHA CINNAMOMIN ELICITS A DEFENCE RESPONSE AGAINST PHYTOPHTHORA CINNAMOMI IN CASTANEA SATIVA." Acta Horticulturae, no. 940 (December 2012): 315–21. http://dx.doi.org/10.17660/actahortic.2012.940.45.
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Dai, Tingting, Aohua Wang, Xiao Yang, Xiaowei Yu, Wen Tian, Yue Xu, and Tao Hu. "PHYCI_587572: An RxLR Effector Gene and New Biomarker in A Recombinase Polymerase Amplification Assay for Rapid Detection of Phytophthora cinnamomi." Forests 11, no. 3 (March 11, 2020): 306. http://dx.doi.org/10.3390/f11030306.
Full textAbstract:
Phytophthora cinnamomi is a devastating pathogen causing root and crown rot and dieback diseases of nearly 5000 plant species. Accurate and rapid detection of P. cinnamomi plays a fundamental role within the current disease prevention and management programs. In this study, a novel effector gene PHYCI_587572 was found as unique to P. cinnamomi based on a comparative genomic analysis of 12 Phytophthora species. Its avirulence homolog protein 87 (Avh87) is characterized by the Arg-Xaa-Leu-Arg (RxLR) motif. Avh87 suppressed the pro-apoptotic protein BAX- and elicitin protein INF1-mediated cell death of Nicotiana benthamiana. Furthermore, a recombinase polymerase amplification-lateral flow dipstick detection assay targeting this P. cinnamomi-specific biomarker was developed. While successfully detected 19 P. cinnamomi isolates of a global distribution, this assay lacked detection of 37 other oomycete and fungal species, including P. parvispora, a sister taxon of P. cinnamomi. In addition, it detected P. cinnamomi from artificially inoculated leaves of Cedrus deodara. Moreover, the RPA-LFD assay was found to be more sensitive than a conventional PCR assay, by detecting as low as 2 pg of genomic DNA in a 50-µL reaction. It detected P. cinnamomi in 13 infested soil samples, while the detection rate was 46.2% using PCR. Results in this study indicated that PHYCI_587572 is a unique biomarker for detecting P. cinnamomi. Although PHYCI_587572 was identified as an effector gene based on the RxLR motif of Avh87 and the avirulence activity on Nicotiana, its exact genetic background and biological function on the natural hosts of P. cinnamomi warrant further investigations.
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Barrett, S., B. L. Shearer, C. E. Crane, and A. Cochrane. "An extinction-risk assessment tool for flora threatened by Phytophthora cinnamomi." Australian Journal of Botany 56, no. 6 (2008): 477. http://dx.doi.org/10.1071/bt07213.
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A risk-assessment tool was used to investigate the risk of extinction from disease caused by Phytophthora cinnamomi to 33 taxa from the Stirling Range National Park, Western Australia. Criteria used to score risk of extinction were the direct impact of P. cinnamomi on taxa, number of extant or extinct populations, percentage of populations infested by P. cinnamomi, proximity and topographical relationship of populations to P. cinnamomi, proximity of populations to tracks and the number of additional threatening processes. Direct impact scores were derived from mortality curves determined from the survival of taxa after soil inoculation with P. cinnamomi in a shade-house environment. On the basis of the total extinction risk score, nine taxa had a ‘very high’, five had a ‘high’, six a ‘moderate’, eight a ‘low’, four a ‘very low’ and one ‘no’ risk of extinction. Whereas the methodology confirmed the current threatened status of nine taxa, it also identified five taxa, not currently listed, to be at ‘high’ risk of extinction. Other threatening processes identified included fire, herbivory, aerial canker disease and climate change. These combine with P. cinnamomi to push taxa further towards extinction. Quantification of risk of extinction identifies taxa at risk and allows for prioritisation of management actions for currently threatened flora. This risk-assessment methodology combined glasshouse inoculation with habitat and ecological data, current in situ disease impact and proximity to disease and vectors, to enable a more comprehensive assessment of extinction risk and may be used in other areas with endemic flora threatened by P. cinnamomi.
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Barnard, E. L., C. E. Cordell, S. P. Gilly, and A. G. Kais. "Comparative Performance of Sand and Longleaf Pines on a Phytophthora Cinnamomi-Infested Sandhill in West Florida." Southern Journal of Applied Forestry 17, no. 2 (May 1, 1993): 90–95. http://dx.doi.org/10.1093/sjaf/17.2.90.
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Abstract Survival, but not growth, of Choctawhatchee sand pine exceeded that of Ocala sand pine on a Phytophthora cinnamomi-infested sandhill in west Florida. However, both varieties exhibited relatively high levels of susceptibility to root disease and mortality caused by P. cinnamomi. Longleaf pine survived significantly better than either variety of sand pine and exhibited an apparent resistance to infection by P. cinnamomi. South. J. Appl. For. 17(2):90-95.
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Midgley, Kayla A., Noëlani van den Berg, and Velushka Swart. "Unraveling Plant Cell Death during Phytophthora Infection." Microorganisms 10, no. 6 (May 31, 2022): 1139. http://dx.doi.org/10.3390/microorganisms10061139.
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Oomycetes form a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, of which several hundred organisms are considered among the most devastating plant pathogens—especially members of the genus Phytophthora. Phytophthora spp. have a large repertoire of effectors that aid in eliciting a susceptible response in host plants. What is of increasing interest is the involvement of Phytophthora effectors in regulating programed cell death (PCD)—in particular, the hypersensitive response. There have been numerous functional characterization studies, which demonstrate Phytophthora effectors either inducing or suppressing host cell death, which may play a crucial role in Phytophthora’s ability to regulate their hemi-biotrophic lifestyle. Despite several advances in techniques used to identify and characterize Phytophthora effectors, knowledge is still lacking for some important species, including Phytophthora cinnamomi. This review discusses what the term PCD means and the gap in knowledge between pathogenic and developmental forms of PCD in plants. We also discuss the role cell death plays in the virulence of Phytophthora spp. and the effectors that have so far been identified as playing a role in cell death manipulation. Finally, we touch on the different techniques available to study effector functions, such as cell death induction/suppression.
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Westbrook, Jared W., Joseph B. James, Paul H. Sisco, John Frampton, Sunny Lucas, and Steven N. Jeffers. "Resistance toPhytophthora cinnamomiin American Chestnut (Castanea dentata) Backcross Populations that Descended from Two Chinese Chestnut (Castanea mollissima) Sources of Resistance." Plant Disease 103, no. 7 (July 2019): 1631–41. http://dx.doi.org/10.1094/pdis-11-18-1976-re.
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Restoration of American chestnut (Castanea dentata) depends on combining resistance to both the chestnut blight fungus (Cryphonectria parasitica) and Phytophthora cinnamomi, which causes Phytophthora root rot, in a diverse population of C. dentata. Over a 14-year period (2004 to 2017), survival and root health of American chestnut backcross seedlings after inoculation with P. cinnamomi were compared among 28 BC3, 66 BC4, and 389 BC3F3families that descended from two BC1trees (Clapper and Graves) with different Chinese chestnut grandparents. The 5% most resistant Graves BC3F3families survived P. cinnamomi infection at rates of 75 to 100% but had mean root health scores that were intermediate between resistant Chinese chestnut and susceptible American chestnut families. Within Graves BC3F3families, seedling survival was greater than survival of Graves BC3and BC4families and was not genetically correlated with chestnut blight canker severity. Only low to intermediate resistance to P. cinnamomi was detected among backcross descendants from the Clapper tree. Results suggest that major-effect resistance alleles were inherited by descendants from the Graves tree, that intercrossing backcross trees enhances progeny resistance to P. cinnamomi, and that alleles for resistance to P. cinnamomi and C. parasitica are not linked. To combine resistance to both C. parasitica and P. cinnamomi, a diverse Graves backcross population will be screened for resistance to P. cinnamomi, survivors bred with trees selected for resistance to C. parasitica, and progeny selected for resistance to both pathogens will be intercrossed.
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Boersma, J. G., D. E. L. Cooke, and K. Sivasithamparam. "A survey of wildflower farms in the south-west of Western Australia for Phytophthora spp. associated with root rots." Australian Journal of Experimental Agriculture 40, no. 7 (2000): 1011. http://dx.doi.org/10.1071/ea00013.
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A survey of wildflower farms in the south west of Western Australia, was conducted during spring of 1997 and autumn 1998 to determine the prevalence of Phytophthora infestations. Thirty-seven randomly selected farms ranging in size from 0.5 to =30 ha were visited. The main crop plants grown included species of Banksia, Boronia, Chamelaucium, Conospermum, Eucalyptus, Protea, and Leucadendron. Eighteen sites were found to have infestations of Phytophthora. Of these, 14 sites had P. cinnamomi, and 2 sites had P. cryptogea. P. cactorum, P. citricola and P. nicotianae were each found at only single locations. One site was found to have both P. cinnamomi and P. cryptogea. Species of Phytophthora were identified morphologically, isozymically, and using species-specific PCR primers. Not every species could be identified by all 3 methods. There was no apparent association between geographical location and the occurrence of Phytophthora spp.