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1
Helander, M. L., T. N. Sieber, O. Petrini e S. Neuvonen. "Endophytic fungi in Scots pine needles: spatial variation and consequences of simulated acid rain". Canadian Journal of Botany 72, n. 8 (1 agosto 1994): 1108–13. http://dx.doi.org/10.1139/b94-135.
Testo completoAbstract (sommario):
Within- and among-tree variation in assemblages of endophytic fungi in Scots pine (Pinus sylvestris) needles were studied in a subarctic area where background pollution values are low; the effects of tree density and prolonged simulated acid rain on the occurrence of endophytic fungi were investigated. The needle endophyte most frequently isolated was Cenangium ferruginosum, accounting for 64% of all fungal individuals, followed by Cyclaneusma minus (12% of all individuals). Old needles were colonized more frequently by endophytes than young ones. In young needles the colonization by endophytes increased during the summer, whereas in old ones no seasonal variation was detected. Endophyte colonization was positively correlated with stand density and was reduced on pines treated with spring water acidified with either sulphuric acid alone or in combination with nitric acid. In contrast, nitric acid alone did not affect endophyte colonization. Key words: endophytes, needles, pine, Pinus, simulated acid rain, stand density.
2
Tiwari, Pragya, e Hanhong Bae. "Endophytic Fungi: Key Insights, Emerging Prospects, and Challenges in Natural Product Drug Discovery". Microorganisms 10, n. 2 (4 febbraio 2022): 360. http://dx.doi.org/10.3390/microorganisms10020360.
Testo completoAbstract (sommario):
Plant-associated endophytes define an important symbiotic association in nature and are established bio-reservoirs of plant-derived natural products. Endophytes colonize the internal tissues of a plant without causing any disease symptoms or apparent changes. Recently, there has been a growing interest in endophytes because of their beneficial effects on the production of novel metabolites of pharmacological significance. Studies have highlighted the socio-economic implications of endophytic fungi in agriculture, medicine, and the environment, with considerable success. Endophytic fungi-mediated biosynthesis of well-known metabolites includes taxol from Taxomyces andreanae, azadirachtin A and B from Eupenicillium parvum, vincristine from Fusarium oxysporum, and quinine from Phomopsis sp. The discovery of the billion-dollar anticancer drug taxol was a landmark in endophyte biology/research and established new paradigms for the metabolic potential of plant-associated endophytes. In addition, endophytic fungi have emerged as potential prolific producers of antimicrobials, antiseptics, and antibiotics of plant origin. Although extensively studied as a “production platform” of novel pharmacological metabolites, the molecular mechanisms of plant–endophyte dynamics remain less understood/explored for their efficient utilization in drug discovery. The emerging trends in endophytic fungi-mediated biosynthesis of novel bioactive metabolites, success stories of key pharmacological metabolites, strategies to overcome the existing challenges in endophyte biology, and future direction in endophytic fungi-based drug discovery forms the underlying theme of this article.
3
Hou, QinZheng, DaWei Chen, Yu-pei Wang, Nurbiye Ehmet, Jing Ma e Kun Sun. "Analysis of endophyte diversity of Gentiana officinalis among different tissue types and ages and their association with four medicinal secondary metabolites". PeerJ 10 (30 agosto 2022): e13949. http://dx.doi.org/10.7717/peerj.13949.
Testo completoAbstract (sommario):
Background The difference of metabolites in medicinal plants has always been concerned to be influenced by external environmental factors. However, the relationship between endophytes and host metabolites remains unclear. Methods In this study, we used 16S and ITS amplicon sequencing to compare endophyte diversity among different tissue types and ages of Gentiana officinalis. Endophyte diversity and abundance was also analyzed in relation to the abundance of four secondary metabolites (Gentiopicroside, Loganic acid, Swertiamarine and Sweroside). Results The diversity and richness of G. officinalis endophyte differed as a function of tissue types and ages. Four metabolites of G. officinalis were significantly correlated with the abundance of dominant endophyte genera. The predictive function analysis showed that metabolism was main function of endophytic bacteria in different tissue and year root samples, while saprotroph was dominant trophic modes of endophytic fungi in the different year root samples. The dominant trophic modes of endophytic fungi was saprotroph and pathotroph, and relative abundances differed in the different tissue samples. The results of this study will help to elucidate the plant-microbial interactions and provide key information on the role of endophytes in the production of G.officinalis and its important metabolites.
4
West, E. R., E. J. Cother, C. C. Steel e G. J. Ash. "The characterization and diversity of bacterial endophytes of grapevine". Canadian Journal of Microbiology 56, n. 3 (marzo 2010): 209–16. http://dx.doi.org/10.1139/w10-004.
Testo completoAbstract (sommario):
The diversity of culturable and nonculturable bacterial endophytes of grapevine ( Vitis vinifera L.) was examined using a combination of cultivation and molecular methods. Entire grapevines were sampled to characterize bacterial diversity from different locations throughout the vine. Gas chromatography of fatty acid methyl esters (FAMEs) was used to identify culturable isolates prior to subsequent further microbiological characterization, whilst denaturing gradient gel electrophoresis (DGGE) was used to profile the ribosomal DNA of the bacterial endophyte community extracted from grapevines. Gas chromatography of FAMEs identified 75% of culturable bacterial endophytes to genus level (similarity index >0.3). Many isolates were identified as Bacillus spp., Pseudomonas spp., and Curtobacterium spp. Additionally, actinomycetes are reported for the first time as endophytes of grapevines, with a number of isolates identified as Streptomyces spp. DGGE was successfully used to identify major bands present in samples and indicated a degree of homogeneity of bacterial endophyte community profiles within the grapevines sampled. The major bacterial bands were sequenced and used in identification. Comparison with bacterial markers produced from cultured bacterial endophytes suggested that bacteria in the DGGE profiles were not the species most commonly cultured. Additional research demonstrated similarities between epiphytic and endophytic populations and examined potential entry vectors. Endophyte entry was demonstrated in both field-grown and potted grapevines (‘Chardonnay’) using a rifampicin-resistant Bacillus cereus mutant. The possibility of grapevine epiphytes becoming endophytes, if the opportunity arises, was supported by comparison of gas chromatography of FAMEs from epiphytic and endophytic populations. This research adds grapevine bacterial endophyte communities to those that have been characterized by a multifaceted approach.
5
Moricca, S., e A. Ragazzi. "Fungal Endophytes in Mediterranean Oak Forests: A Lesson from Discula quercina". Phytopathology® 98, n. 4 (aprile 2008): 380–86. http://dx.doi.org/10.1094/phyto-98-4-0380.
Testo completoAbstract (sommario):
Fungal endophytes that colonize forest trees are widespread, but they are less well known than endophytes infecting grasses. The few studies on endophytes in trees mainly concern the tropical areas and the northernmost latitudes, while similar investigations in the Mediterranean region have so far been scarce and incidental. Endophytes are studied mostly in economically important forests suffering from diseases, such as oak forests. One common endophyte that has received some study on oak is the mitosporic Discula quercina. This paper, after first addressing some basic problems on tree endophytes, examines the ecology of D. quercina in Mediterranean oak stands. D. quercina is usually viewed as a symptomless colonizer of healthy Quercus cerris, infecting new leaves early in the growing season, in an unstable equilibrium between transient mutualism/neutralism and latent pathogenesis. It is postulated here that climatic factors can change the endophytic nature of D. quercina, turning it into a weak pathogen or an opportunistic invader of senescing and indeed healthy trees. It is argued more generally that stochastic events can cause the lifestyle of an endophyte to switch from beneficial/neutral to pathogenic, transforming the tree–endophyte interaction, an interaction that depends in part on the matching genomes of the tree and endophyte, and on the environmental context.
6
Conn, Vanessa M., e Christopher M. M. Franco. "Effect of Microbial Inoculants on the Indigenous Actinobacterial Endophyte Population in the Roots of Wheat as Determined by Terminal Restriction Fragment Length Polymorphism". Applied and Environmental Microbiology 70, n. 11 (novembre 2004): 6407–13. http://dx.doi.org/10.1128/aem.70.11.6407-6413.2004.
Testo completoAbstract (sommario):
ABSTRACT The effect of single actinobacterial endophyte seed inoculants and a mixed microbial soil inoculant on the indigenous endophytic actinobacterial population in wheat roots was investigated by using the molecular technique terminal restriction fragment length polymorphism (T-RFLP). Wheat was cultivated either from seeds coated with the spores of single pure actinobacterial endophytes of Microbispora sp. strain EN2, Streptomyces sp. strain EN27, and Nocardioides albus EN46 or from untreated seeds sown in soil with and without a commercial mixed microbial soil inoculant. The endophytic actinobacterial population within the roots of 6-week-old wheat plants was assessed by T-RFLP. Colonization of the wheat roots by the inoculated actinobacterial endophytes was detected by T-RFLP, as were 28 to 42 indigenous actinobacterial genera present in the inoculated and uninoculated plants. The presence of the commercial mixed inoculant in the soil reduced the endophytic actinobacterial diversity from 40 genera to 21 genera and reduced the detectable root colonization by approximately half. The results indicate that the addition of a nonadapted microbial inoculum to the soil disrupted the natural actinobacterial endophyte population, reducing diversity and colonization levels. This was in contrast to the addition of a single actinobacterial endophyte to the wheat plant, where the increase in colonization level could be confirmed even though the indigenous endophyte population was not adversely affected.
7
Hata, Kunihiko, e Kazuyoshi Futai. "Endophytic fungi associated with healthy pine needles and needles infested by the pine needle gall midge, Thecodiplosis japonensis". Canadian Journal of Botany 73, n. 3 (1 marzo 1995): 384–90. http://dx.doi.org/10.1139/b95-040.
Testo completoAbstract (sommario):
The endophytic mycobiota of the galls of pine needle gall midge, Thecodiplosis japonensis, and healthy current-year needles of Pinus densiflora and the F2 hybrid pine (Pinus thunbergii × (P. thunbergii × P. densiflora)) was compared. Phialocephala sp. was the dominant endophyte isolated from the galls and from the basal regions of healthy needles. Species richness in endophytes was facilitated in galls compared to the basal region of healthy needles, and the commencement of their colonization was hastened in galls. In the early stages of gall formation, however, no endophyte was isolated, suggesting that gall endophytes are not carried into the galls by the midge. Endophytes of healthy and galled pine needles were divided into two groups: position-specific fungi, which showed intrinsically restricted distributions on needles; and gall-specific fungi. These two groups might represent different ecological groups of endophytes. Possible interactions between endophytes and the pine needle gall midge are also discussed. Key words: endophytic fungi, Pinus densiflora, F2 hybrid pine, pine needle gall midge.
8
Caruso, Gianluca, Magdi T. Abdelhamid, Andrzej Kalisz e Agnieszka Sekara. "Linking Endophytic Fungi to Medicinal Plants Therapeutic Activity. A Case Study on Asteraceae". Agriculture 10, n. 7 (10 luglio 2020): 286. http://dx.doi.org/10.3390/agriculture10070286.
Testo completoAbstract (sommario):
Endophytes are isolated from every plant species investigated to date, so the metabolome coevolution has been affecting the plants’ (microbiota) ethnobotanic, especially therapeutic, usage. Asteraceae fulfill the rationale for plant selection to isolate endophytes since most of the species of this family have a long tradition of healing usage, confirmed by modern pharmacognosy. The present review compiles recent references on the endophyte−Asteraceae spp. interactions, targeting the secondary metabolites profile as created by both members of this biological system. Endophyte fungi associated with Asteraceae have been collected globally, however, dominant taxa that produce bioactive compounds were specific for the plant populations of different geographic origins. Endophytic fungi richness within the host plant and the biological activity were positively associated. Moreover, the pharmacological action was linked to the plant part, so differential forms of biological interactions in roots, stem, leaves, inflorescences were developed between endophytic fungi and host plants. The comparative analysis of the Asteraceae host and/or fungal endophyte therapeutic activity showed similarities that need a future explanation on the metabolome level.
9
Oliveira, João Arthur dos Santos, Andressa Domingos Polli, Julio Cesar Polonio, Ravely Casarotti Orlandelli, Hélio Conte, João Lúcio Azevedo e João Alencar Pamphile. "Bioprospection and molecular phylogeny of culturable endophytic fungi associated with yellow passion fruit". Acta Scientiarum. Biological Sciences 42 (1 luglio 2020): e48321. http://dx.doi.org/10.4025/actascibiolsci.v42i1.48321.
Testo completoAbstract (sommario):
Endophytic microorganisms live inside the plants without causing any damage to their hosts. In the agricultural field, these endophytes might be a strategy of biological control for phytopathogens. We aimed to isolate endophytic fungi from yellow passion fruit (Passiflora edulis) leaves, evaluating its biocontrol capacity by in vitro antagonism against phytopathogen Colletotrichum sp. CNPU378. We also carried out greenhouse experiments in bean seedlings. A high colonization frequency was obtained (89%), and the molecular identification based on DNA sequencing attested Colletotrichum as the most frequent genus and minor occurrence of Curvularia endophytes. The endophytes tested showed different types of competitive interactions in in vitro antagonism inhibition rate ranging from 28.8 to 48.8%. There were 10 promising antagonists tested for their antagonist activity of crude extracts of secondary metabolites, in which strain PE-36 (20.8%) stood out among the other strains evaluated. In the greenhouse assay, plants inoculated only with endophyte Colletotrichum sp. PE-36 was symptomless and suggest that the endophyte strengthened the growth promotion in common bean plants, especially in the root length and number of leaves when compared to control plants and other treatments. Despite many fungi of Colletotrichum genus being described as causative agents of anthracnose, in this study, the plant sampled was colonized predominantly by Colletotrichum endophytes living in asymptomatic relationship. By the way, we come across a Colletotrichum sp. endophyte able to antagonize a Colletotrichum sp. pathogen.
10
Hettiarachchige, Inoka K., Christy J. Vander Jagt, Ross C. Mann, Timothy I. Sawbridge, German C. Spangenberg e Kathryn M. Guthridge. "Global Changes in Asexual Epichloë Transcriptomes during the Early Stages, from Seed to Seedling, of Symbiotum Establishment". Microorganisms 9, n. 5 (4 maggio 2021): 991. http://dx.doi.org/10.3390/microorganisms9050991.
Testo completoAbstract (sommario):
Asexual Epichloë fungi are strictly seed-transmitted endophytic symbionts of cool-season grasses and spend their entire life cycle within the host plant. Endophyte infection can confer protective benefits to its host through the production of bioprotective compounds. Inversely, plants provide nourishment and shelter to the resident endophyte in return. Current understanding of the changes in global gene expression of asexual Epichloë endophytes during the early stages of host-endophyte symbiotum is limited. A time-course study using a deep RNA-sequencing approach was performed at six stages of germination, using seeds infected with one of three endophyte strains belonging to different representative taxa. Analysis of the most abundantly expressed endophyte genes identified that most were predicted to have a role in stress and defence responses. The number of differentially expressed genes observed at early time points was greater than those detected at later time points, suggesting an active transcriptional reprogramming of endophytes at the onset of seed germination. Gene ontology enrichment analysis revealed dynamic changes in global gene expression consistent with the developmental processes of symbiotic relationships. Expression of pathway genes for biosynthesis of key secondary metabolites was studied comprehensively and fuzzy clustering identified some unique expression patterns. Furthermore, comparisons of the transcriptomes from three endophyte strains in planta identified genes unique to each strain, including genes predicted to be associated with secondary metabolism. Findings from this study highlight the importance of better understanding the unique properties of individual endophyte strains and will serve as an excellent resource for future studies of host-endophyte interactions.
11
Pitakbut, Thanet, Michael Spiteller e Oliver Kayser. "Genome Mining and Gene Expression Reveal Maytansine Biosynthetic Genes from Endophytic Communities Living inside Gymnosporia heterophylla (Eckl. and Zeyh.) Loes. and the Relationship with the Plant Biosynthetic Gene, Friedelin Synthase". Plants 11, n. 3 (25 gennaio 2022): 321. http://dx.doi.org/10.3390/plants11030321.
Testo completoAbstract (sommario):
Even though maytansine was first discovered from Celastraceae plants, it was later proven to be an endophytic bacterial metabolite. However, a pure bacterial culture cannot synthesize maytansine. Therefore, an exclusive interaction between plant and endophytes is required for maytansine production. Unfortunately, our understanding of plant–endophyte interaction is minimal, and critical questions remain. For example: how do endophytes synthesize maytansine inside their plant host, and what is the impact of maytansine production in plant secondary metabolites? Our study aimed to address these questions. We selected Gymnosporia heterophylla as our model and used amino-hydroxybenzoic acid (AHBA) synthase and halogenase genes as biomarkers, as these two genes respond to biosynthesize maytansine. As a result, we found a consortium of seven endophytes involved in maytansine production in G. heterophylla, based on genome mining and gene expression experiments. Subsequently, we evaluated the friedelin synthase (FRS) gene’s expression level in response to biosynthesized 20-hydroxymaytenin in the plant. We found that the FRS expression level was elevated and linked with the expression of the maytansine biosynthetic genes. Thus, we achieved our goals and provided new evidence on endophyte–endophyte and plant–endophyte interactions, focusing on maytansine production and its impact on plant metabolite biosynthesis in G. heterophylla.
12
MURPHY, B. R., F. M. DOOHAN e T. R. HODKINSON. "Fungal endophytes of barley roots". Journal of Agricultural Science 152, n. 4 (13 giugno 2013): 602–15. http://dx.doi.org/10.1017/s0021859613000348.
Testo completoAbstract (sommario):
SUMMARYFungal infections of barley have tremendous agricultural significance, and can be detrimental or beneficial. Beneficial root infections often involve endophytic fungi, but endophytic associations do not always confer benefits on their hosts. Endophyte infection can be negative, positive or neutral for the host. Benefits to barley and other plants infected with endophytic root fungi include an increase in seed yield, enhanced resistance to pathogens and improved stress tolerance. Even if an endophyte is never pathogenic, it is not always beneficial. The most important factors that determine the nature of the relationship are the specific combination of partner genotypes and developmental stage, and the ecological and environmental setting. The nutrient status of the plant and the availability of soil nutrients may have little effect on the degree of beneficial endophyte colonization and, unlike mycorrhizae, there is no apparent increase in endophyte-associated phosphorous transfer. There are indications of an association between successful endophyte colonization and high soil pH and clay content. The greatest benefits to the barley plant resulting from the associations seem to be obtained in abiotically stressed environments. Fungal infection may give the plant a greater ability to cope with the stress if the partners are in a balanced relationship. Each new study reveals an increasing diversity of beneficial fungal root endophytes and the full potential of these organisms is still to be determined. Further studies are urgently required to develop specific beneficial root–endophyte associations, or combination of them, that are tailored to individual barley varieties for maximum impact in agriculture.
13
Chen, Yaqi, Kaiqi Su, Chunjie Li e James F. White. "Interactive Effects of Epichloë Endophyte, Dormancy-Breaking Treatments and Geographic Origin on Seed Germination of Achnatherum inebrians". Microorganisms 9, n. 11 (20 ottobre 2021): 2183. http://dx.doi.org/10.3390/microorganisms9112183.
Testo completoAbstract (sommario):
Background: the cool-season grass Achnatherum inebrians (drunken horse grass) is an important species in the northwest grasslands of China. This grass engages in a symbiotic relationship with Epichloë endophytes, which affect host plants by increasing growth, repelling herbivores, and increasing tolerance to stressful environments. Methods: in this work, we evaluated the interaction effects of the endophyte on various dormancy-breaking treatments on A. inebrians seeds from six different locations. We used both endophyte-infected plants and noninfected plants and applied four dormancy-breaking methods to test germination. Results: our results showed that the germination rate of endophytic Achnatherum inebrians seeds from the Xiahe site (with highest altitude) was significantly higher than that from other sites when water soaking was applied (p < 0.05). Endophytic seeds had a greater germination rate, and soluble sugar, indole acetic acid (IAA), and gibberellin (GA) contents, under any condition. There was a significant interaction among the method, endophyte status, and origin regarding germination (p < 0.001); particularly, the effects of warm water soaking and endophyte infection on the germination of seeds from the Xiahe site was significant (p < 0.05). Conclusions: the infection of Epichloë endophyte is able to increase the content of soluble sugar, IAA, and GA, and stimulate the seed germination of A. inebrians.
14
Hata, Kunihiko, Kazuyoshi Futai e Mitsuya Tsuda. "Seasonal and needle age-dependent changes of the endophytic mycobiota in Pinus thunbergii and Pinus densiflora needles". Canadian Journal of Botany 76, n. 2 (1 febbraio 1998): 245–50. http://dx.doi.org/10.1139/b97-177.
Testo completoAbstract (sommario):
Monthly changes in the endophytic mycobiota in Pinus thunbergii Parl. and Pinus densiflora Sieb. et Zucc. needles were detected by tissue culture. Endophytic mycobiota of these pine needles were dominated by four taxa: the Leptostroma anamorph of the Lophodermium pinastri (Schrad. ex Hook.) Chev. complex, Phialocephala sp., Cenangium ferruginosum Fr.:Fr., and an unidentified hyphomycete species (BrS). The mycobiota differed with host pine species, position on the needle, and needle age. Virtually no endophytes were detected in needles just after emergence, but most segments of the older needles harbored endophytes. The endophytic mycobiota changed slowly with needle aging, except for the periods of rapid increase in the detection frequency of Leptostroma and Phialocephala sp. Detection frequency of Leptostroma, the most frequently detected endophyte taxon in the needles of the two pine species, continuously increased with needle aging, while that of Phialocephala sp., the endophyte mainly detected from the basal segments of Pinus densiflora, slowly decreased with needle aging after a massive emergence in current-year needles.Key words: Pinus thunbergii, Pinus densiflora, pine needle, endophytic fungi.
15
Bittleston, L. S., F. Brockmann, W. Wcislo e S. A. Van Bael. "Endophytic fungi reduce leaf-cutting ant damage to seedlings". Biology Letters 7, n. 1 (7 luglio 2010): 30–32. http://dx.doi.org/10.1098/rsbl.2010.0456.
Testo completoAbstract (sommario):
Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high ( E high ) or low ( E low ) densities of endophytes. The E high seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the E low treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from E low relative to E high seedlings and had a tendency to recruit more ants to E low plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities.
16
Nwankwo, Ogechukwu L., Onwuzuluigbo C. Chukwuebuka, Okeke O. Collins, Bunu J. Samuel, Josephat C. Obasi, Ezinne S. Iloh e Emmanuel Okechukwu Nwankwo. "Quantitative phytochemical analysis of the fungus endophytic extracts isolated from Azadirachta indica using gas chromatography- flame ionization detector". Journal of Drug Delivery and Therapeutics 11, n. 5 (15 settembre 2021): 80–83. http://dx.doi.org/10.22270/jddt.v11i5.4999.
Testo completoAbstract (sommario):
Background information: The phytochemicals of endophytes have generated substantial interest in drug discovery programs because they offer the possibility of discovering new biologically active molecules. Objective: The objective of this study was to quantify and analyze the phytochemical profile of the fungus endophytic extracts isolated from Azadirachta indica leaves, which have been used ethnobotanically for treating malaria and bacterial infections. Methods: Endophytic fungi were isolated, solid-state fermentation of rice medium was performed, and secondary metabolites were extracted according to standard techniques. An analytical system that uses gas chromatography and flame ionization detection (GC-FID) was used to determine the phytochemical constituents contained in the endophytes. Results: The results of GC-FID analysis showed the presence of Ribalinidine, Naringenin, Sparteine, Phenol, Steroids, Kaempferol, Flavone, Oxalate, Catechin, Tannin, and Rutin at different concentrations. Conclusion: This study reveals the promising ability of the endophytic fungi of A. indica as a foundation of naturally occurring bioactive. The quantitative phytochemical assessment of the endophyte extracts from the leaves of A.indica showed that endophyte extracts from the plant are rich in both alkaloids and flavonoids (Phenolics).
Keywords: GC-FID, Phytochemical, Endophytes, Secondary metabolites, Fermentation.
17
Suryanarayanan, T. S., T. S. Murali e G. Venkatesan. "Occurrence and distribution of fungal endophytes in tropical forests across a rainfall gradient". Canadian Journal of Botany 80, n. 8 (1 agosto 2002): 818–26. http://dx.doi.org/10.1139/b02-069.
Testo completoAbstract (sommario):
Fungal endophytes occur in leaves of angiosperm and gymnosperm trees. The occurrence and distribution of fungal endophytes in the leaves of trees growing in four different types of tropical forests in the Western Ghats were studied. One thousand five hundred leaf segments from five different hosts were screened for each forest type. Endophyte communities of trees of the semi-evergreen forest showed the highest species diversity. More endophyte isolates were recovered during the wet season. Although several genera of endophytes were common for different hosts growing in different forests, the dominant endophyte was different for different forest types. Our results suggest that although tropical trees individually may be endophyte rich, the overall endophyte diversity of the entire plant community is not exceptional.Key words: tropical forests, fungal endophytes, fungal diversity, foliar endophytes.
18
Asad, Suhail, Pengbo He, Pengfei He, Yongmei Li, Yixin Wu, Ayesha Ahmed, Yunyue Wang, Shahzad Munir e Yueqiu He. "Interactions between Indigenous Endophyte Bacillus subtilis L1-21 and Nutrients inside Citrus in Reducing Huanglongbing Pathogen Candidatus Liberibacter Asiaticus". Pathogens 10, n. 10 (12 ottobre 2021): 1304. http://dx.doi.org/10.3390/pathogens10101304.
Testo completoAbstract (sommario):
Huanglongbing (HLB) pathogen Candidatus Liberibacter asiaticus (CLas) brings a great concern about the phloem nutrient transport in diseased plants. There is an urgent need to find the best management strategies to reduce the losses in the citrus industry worldwide. Endophytic bacteria are negatively affected by CLas pathogen, and these endophytes are associated with improved availability of nutrients and pathogen resistance. This study underpins the relationship between CLas pathogen, endophyte population and nutrients availability in citrus plants. The citrus plants were treated with Bacillus subtilis L1-21 and Hoagland solution to find out synergism efficacy to mitigate citrus HLB. We showed that citrus shoots in the presence of 50% Hoagland solution displayed maximum number of endophytes with 6.28 × 103 to 3.04 × 105 CFU/g. Among 50 candidate strains, B. subtilis L1-21 emerged as potential antagonist against surrogate strain Xanthomonas citri subsp. citri. The citrus half-leaf method identified that application of endophyte L1-21 with 50% Hoagland solution successfully reduces the CLas abundance. We point out that this combination results in a higher number of endophytes population with 2.52 × 104 to 9.11 × 106 CFU/g after 60 days, and reduces CLas pathogen abundance in asymptomatic HLB plants. In HLB symptomatic citrus plants, B. subtilis L1-21 potentially increases the endophyte population from 1.11 × 104 to 5.26 × 107 CFU/g in the presence of Hoagland solution, and pathogen abundance was reduced from 9.51 × 105 to 1.06 × 104 copies/g. Altogether, we suggested that the presence of endophyte L1-21 with Hoagland solution is more effective in HLB asymptomatic citrus plants, but a slight reduction of pathogen was observed in symptomatic plants. The findings revealed the role of indigenous citrus endophyte B. subtilis L1-21 along with other nutrients in the reduction of CLas pathogen abundance inside symptomatic and asymptomatic plants in citrus endophyte–nutrient–pathogen interplay.
19
Jing, Minyu, Xihui Xu, Jing Peng, Can Li, Hanchao Zhang, Chunlan Lian, Yahua Chen, Zhenguo Shen e Chen Chen. "Comparative Genomics of Three Aspergillus Strains Reveals Insights into Endophytic Lifestyle and Endophyte-Induced Plant Growth Promotion". Journal of Fungi 8, n. 7 (29 giugno 2022): 690. http://dx.doi.org/10.3390/jof8070690.
Testo completoAbstract (sommario):
Aspergillus includes both plant pathogenic and beneficial fungi. Although endophytes beneficial to plants have high potential for plant growth promotion and improving stress tolerance, studies on endophytic lifestyles and endophyte-plant interactions are still limited. Here, three endophytes belonging to Aspergillus, AS31, AS33, and AS42, were isolated. They could successfully colonize rice roots and significantly improved rice growth. The genomes of strains AS31, AS33, and AS42 were sequenced and compared with other Aspergillus species covering both pathogens and endophytes. The genomes of AS31, AS33, and AS42 were 36.8, 34.8, and 35.3 Mb, respectively. The endophytic genomes had more genes encoding carbohydrate-active enzymes (CAZymes) and small secreted proteins (SSPs) and secondary metabolism gene clusters involved in indole metabolism than the pathogens. In addition, these endophytes were able to improve Pi (phosphorus) accumulation and transport in rice by inducing the expression of Pi transport genes in rice. Specifically, inoculation with endophytes significantly increased Pi contents in roots at the early stage, while the Pi contents in inoculated shoots were significantly increased at the late stage. Our results not only provide important insights into endophyte-plant interactions but also provide strain and genome resources, paving the way for the agricultural application of Aspergillus endophytes.
20
Ashraf, Sobia, Muhammad Afzal, Khadeeja Rehman, Muhammad Naveed e Zahir Ahmad Zahir. "Plant-endophyte synergism in constructed wetlands enhances the remediation of tannery effluent". Water Science and Technology 77, n. 5 (2 gennaio 2018): 1262–70. http://dx.doi.org/10.2166/wst.2018.004.
Testo completoAbstract (sommario):
Abstract Liquid effluent produced from tanning industries is loaded with organic and inorganic contaminants, particularly heavy metals, which may cause severe damage to the ecosystem. Constructed wetland (CW) is a promising product of the research in the field of ecological engineering which helps to overcome aquatic pollution. This investigation aims to develop a plant–endophyte synergism in CW for the efficient remediation of tannery effluent. In a vertical flow CW, Brachiaria mutica was vegetated and augmented with three endophytic bacterial strains. Results showed a reduction of 82% in COD, 94% in BOD5, and 95% in Cr by plant–endophyte synergism in CWs and it was significantly higher than the use of plants alone. Similarly, nutrients (N and P), lipids, ion content, SO42−, and Cl− showed similar reduction by the combined action of endophytes and B. mutica in CWs. The endophytes inoculation enhanced bacterial population in different compartments of the plants vegetated in CWs and the maximum was observed in the roots. This study revealed that plant–endophyte synergism in CWs can enhance the remediation of industrial wastewater.
21
Durham, William F., e Michael G. Tannenbaum. "Effects of endophyte consumption on food intake, growth, and reproduction in prairie voles". Canadian Journal of Zoology 76, n. 5 (1 maggio 1998): 960–69. http://dx.doi.org/10.1139/z98-021.
Testo completoAbstract (sommario):
Grasses infected with fungal endophytes are known to deter herbivores. Athough ingestion of infected plant tissues has detrimental effects on insects, birds, domestic livestock, and laboratory rodents, little is known about the consequences of endophyte consumption for wild rodent consumers. This multigenerational study investigated how consumption of tall fescue (Festuca arundinacea) seeds infected with the endophytic fungus Acremonium coenophialum affects prairie voles (Microtus ochrogaster). Breeding pairs were fed one of three base diets: laboratory rodent chow (C; control diet), 50% uninfected tall fescue seeds plus 50% chow (E-), or 50% endophyte-infected seeds plus 50% chow (E+). In the first generation, the E+ diet suppressed food and water intake, growth rates, and reproductive success, so no voles fed on the E+ diet could be followed in the second generation. In general, voles of the two generations performed similarly on the C and E- diets. Our findings show that prairie voles are sensitive to the presence of endophytes, or associated alkaloids, in their diets, and suggest that free-ranging voles avoid consuming endophyte-infected plant tissues if other foods are available.
22
Milne, G. D. "Technology transfer of novel ryegrass endophytes in New Zealand". NZGA: Research and Practice Series 13 (1 gennaio 2007): 237–39. http://dx.doi.org/10.33584/rps.13.2006.3067.
Testo completoAbstract (sommario):
The adoption of novel endophyte ryegrass in New Zealand has been successful and rapid, with AR1 novel endophyte seed representing 80% of the total ryegrass seed infected with endophyte within 3 years of release. Success was underpinned by a large amount of research into endophytes and the animal production benefits of novel endophytes. Awareness amongst farmers and seed retailers was created by scientists and seed company staff, often with an organised and collaborative campaign. The domination of the market with novel endophytes is likely to increase further with the on-farm success of AR1, and the recent introduction of third-generation endophytes. Keywords: endophyte, ryegrass, technology, transfer, adoption, knowledge, awareness, benefits, validation, research
23
OKUNGBOWA, Francisca I., Hakeem O. SHITTU e Henry O. OBIAZIKWOR. "Endophytic Bacteria: Hidden Protective Associates of Plants against Biotic and Abiotic Stresses". Notulae Scientia Biologicae 11, n. 2 (28 giugno 2019): 167–74. http://dx.doi.org/10.15835/nsb11210423.
Testo completoAbstract (sommario):
An endophyte is a microorganism, usually bacterium or fungus, which lives within the internal tissue of a host plant, causing no apparent harm. Some characteristics of an endophyte include ability to promote plant growth and to confer plant tolerance to biotic and abiotic stresses. Endophytic bacteria spread across many phyla including the Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. Endophytic bacteria are recruited by hosts and they get attached to the surface and eventually find their way into the internal tissues where they spread to the intercellular spaces of host plants. These bacteria have been isolated and characterized from different plants. Currently, culture-independent methods such as sequencing of the 16S rRNA gene or metalogenomics are used for identification and characterization of endophytes. The mechanisms by which the endophyte-induced plant protection is brought about can be through direct and/or indirect methods. The direct strategy antagonizes phytopathogens by the production of chemical substances while the indirect mechanisms improve resistance of hosts to pathogens. Global gene expression studies on some common endophytic bacteria implicated these direct and indirect strategies of bacterial-induced protection. More research should be geared towards how the economic importance of endophytic bacteria could be utilized to enhance global food security.
24
Sessitsch, A., P. Hardoim, J. Döring, A. Weilharter, A. Krause, T. Woyke, B. Mitter et al. "Functional Characteristics of an Endophyte Community Colonizing Rice Roots as Revealed by Metagenomic Analysis". Molecular Plant-Microbe Interactions® 25, n. 1 (gennaio 2012): 28–36. http://dx.doi.org/10.1094/mpmi-08-11-0204.
Testo completoAbstract (sommario):
Roots are the primary site of interaction between plants and microorganisms. To meet food demands in changing climates, improved yields and stress resistance are increasingly important, stimulating efforts to identify factors that affect plant productivity. The role of bacterial endophytes that reside inside plants remains largely unexplored, because analysis of their specific functions is impeded by difficulties in cultivating most prokaryotes. Here, we present the first metagenomic approach to analyze an endophytic bacterial community resident inside roots of rice, one of the most important staple foods. Metagenome sequences were obtained from endophyte cells extracted from roots of field-grown plants. Putative functions were deduced from protein domains or similarity analyses of protein-encoding gene fragments, and allowed insights into the capacities of endophyte cells. This allowed us to predict traits and metabolic processes important for the endophytic lifestyle, suggesting that the endorhizosphere is an exclusive microhabitat requiring numerous adaptations. Prominent features included flagella, plant-polymer-degrading enzymes, protein secretion systems, iron acquisition and storage, quorum sensing, and detoxification of reactive oxygen species. Surprisingly, endophytes might be involved in the entire nitrogen cycle, as protein domains involved in N2-fixation, denitrification, and nitrification were detected and selected genes expressed. Our data suggest a high potential of the endophyte community for plant-growth promotion, improvement of plant stress resistance, biocontrol against pathogens, and bioremediation, regardless of their culturability.
25
Popay, A. J., e B. A. Tapper. "Endophyte effects on consumption of seed and germinated seedlings of ryegrass and fescue by grass grub (Costelytra zealandica) larvae". NZGA: Research and Practice Series 13 (1 gennaio 2007): 353–55. http://dx.doi.org/10.33584/rps.13.2006.3168.
Testo completoAbstract (sommario):
Tall fescue, meadow fescue and ryegrass seeds with and without endophyte infection were fed to third-instar grass grub to determine the relative effects of different endophytes on consumption. Treatments were: tall fescue without endophyte or infected with four novel endophytes (AR514, AR542, AR584, ES), meadow fescue without endophyte or infected with Neotyphodium uncinatum and perennial ryegrass infected with a novel endophyte AR37. Grass grub larvae were initially given hard seed but when they failed to eat this, moist soil was added to allow seed to soften and germinate. After 7 days, all endophytes had reduced feeding compared to their endophytefree counterparts. At the completion of the trial, 15 days after adding moist soil, only AR37 in perennial ryegrass had no effect on damage to the seed. Of the endophytes in tall fescue, seeds containing AR542 were significantly more damaged than other endophyte treatments. Composition of loline alkaloids may be important in reducing feeding. Keywords: tall fescue, meadow fescue, ryegrass, endophytes, loline alkaloids, seed damage, grass grub, Costelytra zealandica
26
Barra-Bucarei, Lorena, Andrés France Iglesias, Macarena Gerding González, Gonzalo Silva Aguayo, Jorge Carrasco-Fernández, Jean Franco Castro e Javiera Ortiz Campos. "Antifungal Activity of Beauveria bassiana Endophyte against Botrytis cinerea in Two Solanaceae Crops". Microorganisms 8, n. 1 (31 dicembre 2019): 65. http://dx.doi.org/10.3390/microorganisms8010065.
Testo completoAbstract (sommario):
Botrytis cinerea causes substantial losses in tomato and chili pepper crops worldwide. Endophytes have shown the potential for the biological control of diseases. The colonization ability of native endophyte strains of Beauveria bassiana and their antifungal effect against B. cinerea were evaluated in Solanaceae crops. Root drenching with B. bassiana was applied, and endophytic colonization capacity in roots, stems, and leaves was determined. The antagonistic activity was evaluated using in vitro dual culture and also plants by drenching the endophyte on the root and by pathogen inoculation in the leaves. Ten native strains were endophytes of tomato, and eight were endophytes of chili pepper. All strains showed significant in vitro antagonism against B. cinerea (30–36%). A high antifungal effect was observed, and strains RGM547 and RGM644 showed the lowest percentage of the surface affected by the pathogen. Native strains of B. bassiana colonized tomato and chili pepper tissues and provided important levels of antagonism against B. cinerea.
27
Kelemu, Segenet, James F. White Jr, Fernando Muñoz e Yuka Takayama. "An endophyte of the tropical forage grass Brachiaria brizantha: Isolating, identifying, and characterizing the fungus, and determining its antimycotic properties". Canadian Journal of Microbiology 47, n. 1 (1 gennaio 2001): 55–62. http://dx.doi.org/10.1139/w00-127.
Testo completoAbstract (sommario):
Brachiaria, predominantly an African genus, contains species, such as B. brizantha, an apomictic C4 grass, that are commercially important forage grasses in tropical America, where they now cover about 55 million hectares. From B. brizantha accession CIAT 6780, we isolated an endophytic fungus that may be economically significant. The fungus was identified as Acremonium implicatum (J. Gilman & E.V. Abott). 18S rDNA and ITS rDNA sequences were used to characterize isolates of the endophyte, and showed that they belonged to the Acremonium genus, being close to A. strictum and A. kiliense. Using the random amplified polymorphic DNA (RAPD) technique, involving arbitrary primers of 10 bases, we showed that the isolates were highly similar to each other. Antiserum produced from a monoconidial culture of A. implicatum isolated from B. brizantha 6780, differentiated the isolates consistently in line with the DNA data. When we compared endophyte-free with endophyte-infected B. brizantha CIAT 6780 plants, both artificially inoculated with the pathogenic Drechslera fungus, we found that the endophyte-infected plants had fewer and smaller lesions than did the endophyte-free plants. Sporulation of Drechslera sp. on artificially inoculated leaf sheath tissues was also much less on tissue infected with the endophyte.Key words: endophytes, Brachiaria, Acremonium, biological control.
28
Hume, D. E., e J. C. Sewell. "Agronomic advantages conferred by endophyte infection of perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.) in Australia". Crop and Pasture Science 65, n. 8 (2014): 747. http://dx.doi.org/10.1071/cp13383.
Testo completoAbstract (sommario):
Perennial ryegrass and tall fescue are key grasses of sown pastures in the high-rainfall zone of south-eastern Australia. Ryegrass in naturalised pastures, and in sown seed, is widely infected with Neotyphodium fungal endophytes, with toxic endophyte strains occasionally causing toxicosis in livestock. Endophyte infection is also beneficial in sown grasslands, assisting ryegrass hosts to overcome biotic stresses, and tall fescue hosts to overcome biotic and abiotic stresses. We review the literature for Australia and present new data, to examine the agronomic effects of endophyte. Frequency of endophyte infection in old, perennial ryegrass pastures and ecotype-based cultivars is high and, in all pastures, increases with time, providing evidence for endophyte-infected plants having an agronomic advantage over endophyte-free plants. Within a cultivar, agronomic field experiments have compared endophyte-infected with endophyte-free swards. Endophyte significantly improved ryegrass establishment in seven of 19 measurements taken from 12 trials. In mature ryegrass pastures, over half of the experiments found advantages to endophyte infection. Tall fescues infected with a selected endophyte (‘AR542’) had improved agronomic performance relative to endophyte-free in a majority of experiments, and on occasions, the endophyte was essential for tall fescue persistence. Cultivar × endophyte interactions occurred but were inconsistent. In high-stress environments, endophyte was more important for agronomic performance than difference between cultivars. The relative importance of cultivar and endophyte is discussed, with elite cultivars that are adapted to the region and are infected with elite endophytes being the best avenue to capture the benefits and minimise detrimental endophyte effects on livestock. The major drivers are likely to be insect pests and drought, but evidence is limited.
29
Young, Carolyn A., Brian A. Tapper, Kimberley May, Christina D. Moon, Christopher L. Schardl e Barry Scott. "Indole-Diterpene Biosynthetic Capability of Epichloë Endophytes as Predicted by ltm Gene Analysis". Applied and Environmental Microbiology 75, n. 7 (30 gennaio 2009): 2200–2211. http://dx.doi.org/10.1128/aem.00953-08.
Testo completoAbstract (sommario):
ABSTRACT Bioprotective alkaloids produced by Epichloë and closely related asexual Neotyphodium fungal endophytes protect their grass hosts from insect and mammalian herbivory. One class of these compounds, known for antimammalian toxicity, is the indole-diterpenes. The LTM locus of Neotyphodium lolii (Lp19) and Epichloë festuce (Fl1), required for the biosynthesis of the indole-diterpene lolitrem, consists of 10 ltm genes. We have used PCR and Southern analysis to screen a broad taxonomic range of 44 endophyte isolates to determine why indole-diterpenes are present in so few endophyte-grass associations in comparison to that of the other bioprotective alkaloids, which are more widespread among the endophtyes. All 10 ltm genes were present in only three epichloë endophytes. A predominance of the asexual Neotyphodium spp. examined contained 8 of the 10 ltm genes, with only one N. lolii containing the entire LTM locus and the ability to produce lolitrems. Liquid chromatography-tandem mass spectrometry profiles of indole-diterpenes from a subset of endophyte-infected perennial ryegrass showed that endophytes that contained functional genes present in ltm clusters 1 and 2 were capable of producing simple indole-diterpenes such as paspaline, 13-desoxypaxilline, and terpendoles, compounds predicted to be precursors of lolitrem B. Analysis of toxin biosynthesis genes by PCR now enables a diagnostic method to screen endophytes for both beneficial and detrimental alkaloids and can be used as a resource for screening isolates required for forage improvement.
30
Del Olmo-Ruiz, Mariana, e A. Elizabeth Arnold. "Community structure of fern-affiliated endophytes in three neotropical forests". Journal of Tropical Ecology 33, n. 1 (2 novembre 2016): 60–73. http://dx.doi.org/10.1017/s0266467416000535.
Testo completoAbstract (sommario):
Abstract:From the saprotrophs that decay plant material to the pathogens and mutualists that shape plant demography at local and regional scales, fungi are major drivers of tropical forest dynamics. Although endophytic fungi are abundant and diverse in many biomes, they reach their greatest diversity in tropical forests, where they can influence plant physiology, performance and survival. The number of quantitative studies regarding endophytes has increased dramatically in the past two decades, but general rules have not yet emerged regarding the biogeography, host affiliations, local or regional distributions, or phylogenetic diversity of endophytes in most tropical settings. Here, endophytic fungal communities associated with 18 species of eupolypod fern were compared among forest reserves in Panama, Costa Rica and Mexico. Molecular sequence data for >2000 isolates were used to determine the relationships of host taxonomy, forest (site), and environmental dissimilarity to endophyte community composition. Communities in related ferns differed significantly among forests, reflecting the interplay of geographic distance and environmental dissimilarity. Although the same phyla and classes of fungi were prevalent at each site, they differed in relative abundance. All sites were dominated by the same order (Xylariales), but sites differed in the phylogenetic clustering vs. evenness of their endophyte communities. By addressing the relationship of endophyte communities to host taxonomy, geographic distance and environmental factors, this study complements previous work on angiosperms and contributes to a growing perspective on the factors shaping communities of ecologically important fungi in tropical forests.
31
Moler, Ehren R. V., Keith Reinhardt, Richard A. Sniezko e Ken Aho. "First Report of Fungal Endophyte Communities and Non-Defensive Phytochemistry of Biocontrol-Inoculated Whitebark Pine Seedlings in a Restoration Planting". Forests 13, n. 6 (25 maggio 2022): 824. http://dx.doi.org/10.3390/f13060824.
Testo completoAbstract (sommario):
Plant endosymbionts (endophytes) influence host plant health and express genotype-dependent ecological relationships with plant hosts. A fungal species intended to confer host plant resistance to a forest pathogen was used as inoculum to test for effects of inoculation on disease resistance, microbiomes, and phytochemistry of a threatened pine species planted in a restoration setting. Correlations of inoculation presence/absence, phytochemistry, spatial location of seedlings, maternal seed sources, and fungal endophytic communities in the foliage of six-year-old whitebark pine (Pinus albicaulis) seedlings were assessed five years after an experimental inoculation of seedlings with foliar endophytic fungi cultured from whitebark pine trees at Crater Lake National Park, including Paramyrothecium roridum. We hypothesized that P. roridum would modify host microbiomes in a manner that combats white pine blister rust disease. Our assessment of seedlings in the field five years after inoculation allowed us to consider whether inoculation stimulated long-lasting changes in microbiome communities and whether effects varied by seedling genetic family. Tests for effects of endophyte inoculation on disease resistance were inconclusive due to current low levels of rust infection observed at the field site. Foliar fungal endophyte richness and Shannon diversity varied with maternal seed sources. Isotopic stoichiometry and phytochemistry did not vary with seedling spatial proximity, inoculation treatment, or maternal seed family. However, endophyte community composition varied with both seedling spatial proximity and maternal seed sources. Endophytic communities did not vary with the inoculation treatment, and the hypothesized biocontrol was not detected in inoculated seedlings. We draw three conclusions from this work: (1) fungal microbiomes of whitebark pine seedlings across our study site did not vary with host phytochemical signatures of ecophysiological status, (2) the inoculation of P. albicaulis seedlings with a mixture of fungal endophytes did not lead to persistent systemic changes in seedling foliar microbiomes, and (3) in correspondence with other studies, our data suggest that maternal seed source and spatial patterns influence fungal endophyte community composition.
32
Tellez, Peter H., Carrie L. Woods, Stephen Formel e Sunshine A. Van Bael. "Relationships between Foliar Fungal Endophyte Communities and Ecophysiological Traits of CAM and C3 Epiphytic Bromeliads in a Neotropical Rainforest". Diversity 12, n. 10 (30 settembre 2020): 378. http://dx.doi.org/10.3390/d12100378.
Testo completoAbstract (sommario):
Vascular epiphytes contribute up to 35% of the plant diversity and foliar biomass of flowering plants. The family Bromeliaceae is a monophyletic group of plants native to the Neotropics. Epiphytic bromeliads form associations with distinct groups of organisms but their relationship with foliar fungal endophytes remain underexplored. In this study we examined the relationship of foliar fungal endophytes to host photosynthetic pathways and associated ecophysiological traits. We sampled the fungal endophyte communities of 67 host individuals in six epiphytic bromeliad species differing in C3 and crassulacean acid metabolism (CAM) photosynthetic pathways. We tested whether endophyte assemblages were associated with ecophysiological leaf traits related to host photosynthetic pathways. Our results indicate that (1) C3 and CAM bromeliads host dissimilar endophyte assemblages, (2) endophyte communities in C3 bromeliads are characterized by variable relative abundances of fungal orders; conversely, CAM associated endophyte communities were characterized by consistent relative abundances of fungal orders, and (3) endophyte communities in bromeliads are distributed along a continuum of leaf toughness and leaf water content. Taken together, our study suggests that host physiology and associated ecophysiological traits of epiphytic bromeliads may represent biotic filters for communities of fungal endophytes in the tropics.
33
Panaccione, Daniel, James Kotcon, Christopher Schardl, Richard Johnson e Joseph Morton. "Ergot alkaloids are not essential for endophytic fungus-associated population suppression of the lesion nematode, Pratylenchus scribneri, on perennial ryegrass". Nematology 8, n. 4 (2006): 583–90. http://dx.doi.org/10.1163/156854106778614074.
Testo completoAbstract (sommario):
AbstractSeveral endophytic fungi of the genus Neotyphodium form symbiotic associations with Lolium spp. grasses and are renowned for production of bioactive alkaloids such as ergot alkaloids. Some of these endophytes make their grass partners less suitable as hosts for endoparasitic nematodes, including Pratylenchus spp. The potential for ergot alkaloids to affect nematode motility was investigated in vitro. Ergovaline, the ergot alkaloid pathway end product of several Neotyphodium spp., was the only ergot alkaloid tested that inhibited motility of Pratylenchus scribneri. The association of ergot alkaloids with nematode population suppression was examined in glasshouse experiments with strains of the perennial ryegrass endophyte Neotyphodium sp. isolate Lp1 (syn. Neotyphodium lolii × Epichloë typhina) that have been genetically modified to lack ergot alkaloids or to have an altered ergot alkaloid profile. Populations of P. scribneri were significantly smaller in pots of perennial ryegrass containing the wild-type, ergot alkaloid-producing endophyte than in pots of endophyte-free perennial ryegrass. Elimination of certain complex ergot alkaloids (ergovaline and lysergic acid amides) in one gene knockout strain, or complete elimination of ergot alkaloids in another, did not affect the ability of the endophyte to suppress populations of nematode. Presence and concentrations of ergot alkaloids in pseudostems were as expected based on presence and genotype of endophyte in each plant, but frequently were undetectable or in low concentration in roots. The data indicate that ergot alkaloids do not contribute significantly to the endophyte-associated suppression of Pratylenchus spp.
34
Pecetti, L., M. Romani, A. M. Carroni, P. Annicchiarico e E. Piano. "The effect of endophyte infection on persistence of tall fescue (Festuca arundinacea Schreb.) populations in two climatically contrasting Italian locations". Australian Journal of Agricultural Research 58, n. 9 (2007): 893. http://dx.doi.org/10.1071/ar06423.
Testo completoAbstract (sommario):
Endophytic fungi may reportedly improve summer persistence in tall fescue (Festuca arundinacea Schreb.). The objective of this study was assessing whether endophytes contributed to better persistence in 2 climatically contrasting Italian locations (Sanluri, Mediterranean climate, 382 mm average rainfall; Lodi, subcontinental climate, 802 mm average rainfall). Twelve populations from Sardinia were evaluated for 4 years in each site with or without nitrogen application. The populations hosted either of 2 endophyte forms (long-conidia, Neotyphodium coenophialum; short-conidia, FaTG-2 group) and belonged to the European race of fescue (hosting N. coenophialum) or the Mediterranean race (hosting FaTG-2). Three European-race commercial varieties (hosting N. coenophialum) were included as controls. The evaluated material was present both in the endophyte-infected and the endophyte-free (after chemical treatment) status. Stand persistence was recorded at the end of each year. The effect of the endophyte presence on persistence was nil in the Mediterranean site and slightly positive in the subcontinental location. Populations of the 2 geographic races had contrasting behaviour in the 2 sites irrespective of their endophyte status. The Mediterranean-race populations persisted well in the Mediterranean environment but not in the subcontinental one, and the reverse occurred for the European-race germplasm (including the controls). The results suggest that Mediterranean conditions may be too extreme for any enhancement of persistence to be solely provided by the endophyte, and highlight the overwhelming importance of the physiological adaptation of the grass germplasm to target environment.
35
Stefani, F. O. P., e J. A. Bérubé. "Evaluation of foliar fungal endophyte incidence in field-grown transgenic Bt white spruce trees". Canadian Journal of Botany 84, n. 10 (ottobre 2006): 1573–80. http://dx.doi.org/10.1139/b06-110.
Testo completoAbstract (sommario):
A total of 770 transgenic Bt white spruce needles were collected and plated on potato dextrose agar to determine their foliar endophyte diversity. The ribosomal internal transcribed spacer regions for 310 foliar endophytes were amplified by polymerase chain reaction (PCR) and digested using CfoI and MspI, which created 21 restriction groups. Isolates from each restriction group were sequenced and compared with reference sequences in GenBank. Eighteen sequence groups were obtained, of which five were identified at the species level. The most common endophytic fungi identified by PCR-RFLP was Lophodermium piceae (incidence of 74.5%). The second and third most common ones were Hypoxylon fragiforme (3.63%) and Lophodermium nitens (3.18%). A statistical analysis performed on the most common endophyte groups showed no statistical difference in endophyte frequency or distribution between the control white spruce needles (nontransgenic) and saplings with constructs containing the reporter gene GUS or the Bt Cry1A(b) gene and kanamycin.
36
Ball, O. J. P., e B. A. Tapper. "The production of loline alkaloids in artificial and natural grass/endophyte associations". Proceedings of the New Zealand Plant Protection Conference 52 (1 agosto 1999): 264–69. http://dx.doi.org/10.30843/nzpp.1999.52.11583.
Testo completoAbstract (sommario):
Infection of grasses by Neotyphodium spp. endophytes is associated with the presence of alkaloids. This study investigated the production of loline alkaloids in endophyte-infected tall fescue, meadow fescue and perennial ryegrass. Most of the grass/endophyte associations were artificially created by inoculating parent plants with different Neotyphodium endophytes. The presence of lolines was dependent upon endophyte species and strain, but host species also influenced which lolines were produced. Concentrations of the different lolines, and the ratio at which they occurred, were also dependent upon endophyte isolate and host species. These findings are significant given that lolines contribute to host resistance against some insect pests.
37
Tian, P., T. N. Le, K. F. Smith, J. W. Forster, K. M. Guthridge e G. C. Spangenberg. "Stability and viability of novel perennial ryegrass host–Neotyphodium endophyte associations". Crop and Pasture Science 64, n. 1 (2013): 39. http://dx.doi.org/10.1071/cp12419.
Testo completoAbstract (sommario):
The temperate pasture grass Lolium perenne L. is commonly found in association with the fungal endophyte Neotyphodium lolii. Viability of both seed and endophyte was evaluated by inoculation of individual genotypes from the host cultivar Bronsyn with six distinct endophyte strains. The resulting populations were subjected to either long-term storage under various temperature conditions, or accelerated ageing (AA) treatments. High temperature storage was detrimental to endophyte viability. The AA variables (relative humidity [RH] and time) and subsequent temperature and duration of storage significantly (P < 0.05) affected both seed germination and endophyte viability. Significant interaction effects between the AA treatment and storage conditions were also observed. Endophyte viability following AA treatment was inversely correlated with both increasing RH and duration of treatment. Differential responses between different endophytes within the Bronsyn host were also apparent. The standard endophyte (SE) strain and the novel endophytes AR1 and AR37 exhibited higher viability than NEA2, NEA3, and NEA6 during seed storage, suggesting the importance of identification and selection for compatible symbiotic associations in agronomic varieties. The observed similarity between assessments of endophyte viability after AA treatments and following long-term storage confirmed the capacity of moderate conditions (e.g. 80% RH for 7 days or 100% RH for 4 days) to predict variation in viability between different endophyte strains.
38
Voisey, C. R., A. K. Khan, Z. A. Park, L. J. Johnson, R. D. Johnson, M. Ramakrishna, M. Cao et al. "Development of an Affymetrux dual species ( Neotyphodium lolii/Lolium perenne) Symbiosis GeneChip". NZGA: Research and Practice Series 13 (1 gennaio 2007): 505–7. http://dx.doi.org/10.33584/rps.13.2006.3136.
Testo completoAbstract (sommario):
The aim of this project was to undertake large scale transcript profiling of endophyte and plant genes during symbiosis, and to determine the impact of targeted endophyte gene deletions on expression of plant and endophyte genes. We have designed and developed an Affymetrix NimbleExpress™ GeneChip® representing expressed sequence tags (ESTs) of the fungal endophyte Neotyphodium lolii Lp19 and its ryegrass host, Lolium perenne. In total, 8511 genes were represented on the microarrays with approximately eleven 25 base pair oligonucleotides per gene. Experiments were conducted to analyse differential expression of genes from endophyte-infected and endophyte-free plant material, and from endophytes grown in culture. In some symbioses, endophytes had targeted mutations in genes involved in signalling, synthesis of secondary metabolites or in genes of unknown function. Here we describe the processes which guided design of the GeneChip®, the results of quality control assessments of hybridised arrays and considerations concerning statistical analyses of gene expression. Keywords: Affymetrix, GeneChip®, NimbleExpress, Neotyphodium lolii, Epichloë festucae, ryegrass, Lolium perenne, endophyte, symbiosis.
39
Huang, Yu-Ling. "Effect of Host, Environment and Fungal Growth on Fungal Leaf Endophyte Communities in Taiwan". Journal of Fungi 6, n. 4 (23 ottobre 2020): 244. http://dx.doi.org/10.3390/jof6040244.
Testo completoAbstract (sommario):
Fungal endophytes inhabit plant tissues without causing disease symptoms. They are highly diverse and distributed globally in all plants that have been investigated. Host, geographic, and environmental effects on endophyte communities have been reported in several studies, but the direct effect of fungal growth rate on endophyte composition has not been tested. To understand the relationship between foliar endophyte composition and fungal growth and to examine the effect of host, elevation, and climatic factors on the foliar endophyte communities, this study examined the foliar endophyte communities of representative gymnosperms and Rhododendron spp. across different elevations of Hehuanshan and Taipingshan forests in Taiwan. The isolation frequency and diversity of foliar endophytes were higher at low elevations than at high elevations. The foliar endophyte community structure differed as a function of host family and forest vegetation type. Elevation, mean annual temperature, and precipitation were significantly correlated with the community structure. Fungal growth rate was correlated with the endophyte abundance, which indicates that fast-growing fungi might have a competitive advantage when coexisting with other fungi in a plant host.
40
Wäli, Piippa R., Marjo Helander, Oiva Nissinen e Kari Saikkonen. "Susceptibility of endophyte-infected grasses to winter pathogens (snow molds)". Canadian Journal of Botany 84, n. 7 (luglio 2006): 1043–51. http://dx.doi.org/10.1139/b06-075.
Testo completoAbstract (sommario):
Neotyphodium endophytes are suggested to be mutualistic symbionts of grasses and regarded as potential biological plant protection agents. We examined the effects of the Neotyphodium endophyte of meadow ryegrass on snow molds in vitro with dual cultures of endophyte and Typhula ishikariensis , and on grass–snow mold interactions in vivo in a greenhouse and in a field experiment. In dual cultures, the endophytes formed an inhibition zone and retarded the growth of T. ishikariensis. In the field experiment, however, the endophyte-infected (E+) meadow ryegrasses were more susceptible to T. ishikariensis than the endophyte-free (E–) grasses. Endophyte infection increased the winter damage of grasses both in greenhouse and in field conditions. After winter, the growth of E+ grasses exceeded the growth of E– plants in the field experiment, indicating the marked tolerance of E+ grasses against winter damage. We detected differences in growth and pathogenesis between the different T. ishikariensis strains and found meadow ryegrass cultivar–endophyte status interaction in the growth of meadow ryegrasses, which highlight the effects of the genetic background of the participants on endophyte–grass–snow mold interactions.
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Liu, Hui, Jing Chen, Tianzi Qin, Xinjian Shi, Yubao Gao e Anzhi Ren. "Removal of Soil Microbes Alters Interspecific Competitiveness of Epichloë Endophyte-Infected over Endophyte-Free Leymus chinensis". Microorganisms 8, n. 2 (6 febbraio 2020): 219. http://dx.doi.org/10.3390/microorganisms8020219.
Testo completoAbstract (sommario):
Epichloë endophytes may not only affect the growth and resistances of host grasses, but may also affect soil environment including soil microbes. Can Epichloë endophyte-mediated modification of soil microbes affect the competitive ability of host grasses? In this study, we tested whether Epichloë endophytes and soil microbes alter intraspecific competition between Epichloë endophyte-colonized (EI) and endophyte-free (EF) Leymus chinensis and interspecific competition between L. chinensis and Stipa krylovii. The results demonstrated that Epichloë endophyte colonization significantly enhanced the intraspecific competitive ability of L. chinensis and that this beneficial effect was not affected by soil microbes. Under interspecific competition, however, significant interactions between Epichloë endophytes and soil microbes were observed. The effect of Epichloë endophytes on interspecific competitiveness of the host changed from positive to neutral with soil microbe removal. Here higher mycorrhizal colonization rates probably contributed to interspecific competitive advantages of EI over EF L. chinensis. Our result suggests that Epichloë endophytes can influence the competitive ability of the host through plant soil feedbacks from the currently competing plant species.
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Shaalan, Roshan, Ludmilla Ibrahim, Falah As-sadi e Walid El Kayal. "Impact of Beauveria bassiana and Metarhizium anisopliae on the Metabolic Interactions between Cucumber (Cucumis sativus L.) and Cucumber Mosaic Virus (CMV)". Horticulturae 8, n. 12 (10 dicembre 2022): 1182. http://dx.doi.org/10.3390/horticulturae8121182.
Testo completoAbstract (sommario):
In natural systems, plant–endophyte interactions are important for reducing abiotic and biotic stresses in plants by producing a variety of metabolites that protect plants from pathogens and herbivores. Biocontrol strategies are increasingly being used as a viable alternative to chemical pesticides. Entomopathogenic fungi (EPF) are one of them, and they have been touted as a successful method for biological pest control in plants. Because EPF strains are sensitive to environmental conditions when sprayed, the recently discovered endophytic behavior of several EPF strains has improved their management. Cucumber mosaic virus (CMV) is one of the most common and serious plant viruses worldwide, infecting over 1200 plant species and being spread by more than 80 aphid species. CMV control is directed towards the use of chemical insecticides to eradicate its insect vectors. Endophytic EPF is currently being studied to control plant virus infection, and antagonistic effects have been reported. Metabolomics is an emerging research field for plant metabolite profiling and is employed to study plant–endophyte interactions. In the present research, metabolomics approaches were conducted to gain information into mechanisms involved in defense against CMV in endophytes Beauveria bassiana and Metarhizium anisopliae (EPF)-treated diseased cucumber plants. In addition, CMV-induced metabolic changes in cucumber plants were investigated. Our analysis indicated large differences in cucumber metabolites due to endophytes application. In total, six hundred and thirty-one metabolites were differentially expressed in endophyte-treated CMV diseased cucumber plants. Regulation of different kinds of amino acids, organic acids, and phenylpropanoids metabolites could provide insight about plant defense mechanism against CMV pathogen. Important metabolites were found to be regulated in diseased cucumber plants due to fungal endophytes treatment that could possibly confer tolerance to CMV disease.
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Rasmussen, S., A. J. Parsons, Q. Liu, H. Xue e J. A. Newman. "High nutrient supply and carbohydrate content reduce endophyte and alkaloid concentration". NZGA: Research and Practice Series 13 (1 gennaio 2007): 135–38. http://dx.doi.org/10.33584/rps.13.2006.3103.
Testo completoAbstract (sommario):
Two controlled environment experiments were performed to test the effects of nitrogen, phosphorus and carbohydrates on endophyte (Neotyphodium lolii) and alkaloid concentrations in ryegrass (Lolium perenne). Three perennial ryegrass cultivars ('high sugar grasses' AberDove and AberDart; control Fennema) that differ in carbohydrate content were infected with three strains of N. lolii (common strain, CS; AR1; AR37). Infected and uninfected plants were grown under high (9 mM) and low (2.25 mM) nitrogen (AberDove, Fennema; CS, AR1, AR37) or under high (2 mM KH2PO4) and low (0.05 mM KH2PO4) phosphorus (AberDart, Fennema; CS, AR1). Quantitative realtime Polymerase Chain Reaction (qPCR) was used to estimate endophyte concentrations in harvested leaf tissues. High N and P supply as well as high carbohydrate content of the host grass reduced endophyte concentrations. Alkaloid production was also reduced under both increased N supply and in the high sugar cultivar, and was linearly related to endophyte concentration (except ergovaline). The results stress the need for wider quantification of fungal endophytes in the grassland/ foliar endophyte context, and have implications for how introducing new cultivars, novel endophytes, or increasing nutrient inputs, affect the role of endophytes in grassland ecosystems. Keywords: Neotyphodium lolii, foliar endophyte, Lolium perenne, perennial ryegrass, qPCR, high sugar ryegrass, nitrogen, phosphate, carbohydrate, AR1, AR37, alkaloids
44
Carroll, George. "Forest endophytes: pattern and process". Canadian Journal of Botany 73, S1 (31 dicembre 1995): 1316–24. http://dx.doi.org/10.1139/b95-393.
Testo completoAbstract (sommario):
Studies on taxonomy, distribution, and possible function have dominated the literature on forest endophytes since these fungi were first noted. Endophyte distributions have been described at a variety of scales ranging from those at a landscape level to those at the finest scales of resolution within a single leaf or patch of bark. At a landscape level, distribution patterns seem to be determined by host specificity, liquid precipitation, canopy cover, and geographic continuity or disjunctness. At the level of the individual stand or tree, height in the crown may become important. At the level of individual branch systems, age of substrate appears the most important factor. At a microscopic scale, tissue specificity, leaf topography, and phenology of the infection process with respect to leaf development all play a role. Endophytic fungi have seldom been found to cause widespread disease in trees; furthermore, their age-specific infection frequencies in conifer needles show continuous increases with needle age, in contrast to needle pathogens in which infections are largely confined to young needles. Endophytes are usually viewed as protective mutualists acting against herbivorous insects and pathogenic fungi. Proof of mutualism requires not only that endophytes be present in tissues under attack and their presence be correlated with, for example, increased insect mortality, but that inoculation experiments and comparisons with uninoculated plant tissues also be done. Such experiments often show no differences between treatment and control plants, results that may be related to unsuccessful inoculation of the endophyte. Such results may also be rooted in an inability to reproduce the biological complexity present in natural forest stands. Multiple infections of single leaves may lead to synergistic interactions of toxins produced by endophytes. Insect herbivores have evolved behavioral responses to the presence of endophytes, and protective mutualism by endophytes may occur only intermittently. Key words: endophyte, distribution, mutualism, gall midge, toxins, coevolution.
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West, C. P., F. Volaire e F. Lelievre. "Tiller survival after drought of 'Grasslands Flecha' tall fescue as influenced by endophyte". NZGA: Research and Practice Series 13 (1 gennaio 2007): 267–69. http://dx.doi.org/10.33584/rps.13.2006.3075.
Testo completoAbstract (sommario):
'Grasslands Flecha' tall fescue exhibits a partial degree of endogenous summer dormancy, a trait that contributes to plant survival during the long, dry summers of Mediterranean regions. Little is understood of the physiological mechanisms involved in summer survival of summer-dormant fescues and the possible role of endophytes. The influence of infection by endophyte strain AR542 in enhancing summer survival in ungrazed field plots and dehydration survival in greenhouse pots was investigated. Tiller population counts from mid-summer drought and autumn recovery showed no significant endophyte effect on survival. Results from the pot trial showed no differences between endophyte-free and endophyte-infected populations for rate of leaf dry-down, tiller-base water content, membrane leakage, or percentage tiller survival. Endophyte-free Flecha exhibited excellent summer survival, suggesting that endophyte infection may not be as critical for stand survival in summer dormant fescues as it is in summer active types. Infecting Flecha with novel endophytes may provide additional insurance against biotic stresses, thereby offering greater overall fitness across a range of environments. Keywords: drought, tall fescue, tiller survival, membrane damage, senescence
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Liu, Jinming, Xiaoyu Ge, Xiaowen Fan, Hui Liu, Yubao Gao e Anzhi Ren. "The Inhibitory Effect of Endophyte-Infected Tall Fescue on White Clover Can Be Alleviated by Glomus mosseae Instead of Rhizobia". Microorganisms 9, n. 1 (5 gennaio 2021): 109. http://dx.doi.org/10.3390/microorganisms9010109.
Testo completoAbstract (sommario):
In artificial ecosystems, mixed planting of gramineous and leguminous plants can have obvious advantages and is very common. Due to their improved growth performances and stress tolerance, endophyte-infected grasses are considered to be ideal plant species for grasslands. However, endophytic fungi can inhibit the growth of neighboring nonhost leguminous plants. In this study, we chose endophyte-infected and endophyte-free tall fescue (Lolium arundinaceum Darbyshire ex. Schreb.) and clover (Trifolium repens) as the experimental materials to explore whether arbuscular mycorrhizal fungi and rhizobium can alleviate the inhibitory effect of endophyte infection on clover. The results showed that endophytic fungi significantly reduced clover biomass. Arbuscular mycorrhizal fungi inoculation significantly increased the biomass of clover in both endophyte-infected tall fescue/clover and endophyte-free tall fescue/clover systems but the beneficial contribution of arbuscular mycorrhizal fungi was more obvious in the endophyte-infected tall fescue/clover system. Rhizobia inoculation could alleviate the detrimental effect of tall fescue on the growth of clover but did not alleviate the detrimental effect of endophyte infection on the growth of clover.
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Wijekoon, Champa, e Zoe Quill. "Fungal endophyte diversity in table grapes". Canadian Journal of Microbiology 67, n. 1 (gennaio 2021): 29–36. http://dx.doi.org/10.1139/cjm-2020-0293.
Testo completoAbstract (sommario):
Plant fungal endophytes are diverse microbial sources that reside inside plants. Grapes (Vitis vinifera) are rich in polyphenols that have beneficial health effects, and recent research has shown that fungal endophytes in grapes may contribute to the production of these polyphenols and may serve as biocontrol agents. In this study, we determined the fungal microbial endophyte diversity in North American table grapes found at a Winnipeg, Manitoba, market. The amplicon internal transcribed spacer (ITS) metagenomics approach was used to profile the fungal communities of the fruit endophyte microbiome of three table grape types. The data supported endophyte diversity in different table grapes, including possible bioactive, saprophytic, and pathogenic fungi. Culturable endophytes were isolated and identified by morphology and ITS amplicon sequencing. The majority of the isolated culturable strains included Alternaria spp. and Cladosporium spp. The results provided evidence of the existence of diverse fungal endophytes isolated and identified from the fruit of the table grapes. These fungal endophytes may have potential in agricultural, industrial, and pharmaceutical applications.
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Brown, Colin. "Consolidated summary of key points from the Ryegrass Endophyte Symposium: a farm consultant's perspective". NZGA: Research and Practice Series 7 (1 gennaio 1999): 157–58. http://dx.doi.org/10.33584/rps.7.1999.3392.
Testo completoAbstract (sommario):
Background on endophytes Endophyte is a fungus, which exists inside individual ryegrass plants, and reproduces through infecting ryegrass seed. Endophytes are very widespread in New Zealand pastures, being present in 70% of ryegrass tillers in Southland, and 99% in the upper North Island. The presence of endophyte confers benefits to the host ryegrass plant, inhibiting its susceptibility to grazing by: • domestic animals. • above ground insects, particularly. (a) Argentine stem weevil (b) Black beetles (c) Mealy bug. General awareness of its existence, and understanding of its role, began in the 1980s, and is still expanding. Knowledge of its existence and impacts now allow us to better explain the reasons for "inexplicable" results from scientific trials before 1980. It may also be a prime cause of summer "ill thrift". The endophyte responsible for ryegrass staggers in cattle, sheep, deer and horses occurs in perennial ryegrass and some hybrid ryegrass plants. Endophytes that have toxic effects on grazing animals also occur in other grass species, for example, the endophyte in roadside tall fescue that causes "fescue foot". However, commercial cultivars of tall fescue sold in New Zealand do not contain toxic endophyte.
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Gottel, Neil R., Hector F. Castro, Marilyn Kerley, Zamin Yang, Dale A. Pelletier, Mircea Podar, Tatiana Karpinets et al. "Distinct Microbial Communities within the Endosphere and Rhizosphere of Populus deltoides Roots across Contrasting Soil Types". Applied and Environmental Microbiology 77, n. 17 (15 luglio 2011): 5934–44. http://dx.doi.org/10.1128/aem.05255-11.
Testo completoAbstract (sommario):
ABSTRACTThe root-rhizosphere interface ofPopulusis the nexus of a variety of associations between bacteria, fungi, and the host plant and an ideal model for studying interactions between plants and microorganisms. However, such studies have generally been confined to greenhouse and plantation systems. Here we analyze microbial communities from the root endophytic and rhizospheric habitats ofPopulus deltoidesin mature natural trees from both upland and bottomland sites in central Tennessee. Community profiling utilized 454 pyrosequencing with separate primers targeting the V4 region for bacterial 16S rRNA and the D1/D2 region for fungal 28S rRNA genes. Rhizosphere bacteria were dominated byAcidobacteria(31%) andAlphaproteobacteria(30%), whereas most endophytes were from theGammaproteobacteria(54%) as well asAlphaproteobacteria(23%). A singlePseudomonas-like operational taxonomic unit (OTU) accounted for 34% of endophytic bacterial sequences. Endophytic bacterial richness was also highly variable and 10-fold lower than in rhizosphere samples originating from the same roots. Fungal rhizosphere and endophyte samples had approximately equal amounts of thePezizomycotina(40%), while theAgaricomycotinawere more abundant in the rhizosphere (34%) than endosphere (17%). Both fungal and bacterial rhizosphere samples were highly clustered compared to the more variable endophyte samples in a UniFrac principal coordinates analysis, regardless of upland or bottomland site origin. Hierarchical clustering of OTU relative abundance patterns also showed that the most abundant bacterial and fungal OTUs tended to be dominant in either the endophyte or rhizosphere samples but not both. Together, these findings demonstrate that root endophytic communities are distinct assemblages rather than opportunistic subsets of the rhizosphere.
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Qin, Junhua, Man Wu, Hui Liu, Yubao Gao e Anzhi Ren. "Endophyte Infection and Methyl Jasmonate Treatment Increased the Resistance of Achnatherum sibiricum to Insect Herbivores Independently". Toxins 11, n. 1 (26 dicembre 2018): 7. http://dx.doi.org/10.3390/toxins11010007.
Testo completoAbstract (sommario):
Alkaloids are usually thought to be responsible for protecting endophyte-infected (EI) grasses from their herbivores. For EI grasses that produce few alkaloids, can endophyte infection enhance their resistance to herbivores? Related studies are limited. In the Inner Mongolian steppe, Achnatherum sibiricum is highly infected by Epichloë endophytes, but produces few alkaloids. Locusts are the common insect herbivores of grasses. In this study, A. sibiricum was used as plant material. Methyl jasmonate (MJ, when applied exogenously, can induce responses similar to herbivore damage) treatment was performed. The effects of endophyte infection and MJ treatment on the resistance of A. sibiricum to Locusta migratoria were studied. We found that locusts preferred EF (endophyte-free) plants to EI plants in both choice and no-choice feeding experiments. Endophyte infection enhanced the resistance of A. sibiricum to locusts. Endophyte infection decreased soluble sugar concentrations, while it increased the total phenolic content and phenylalanine ammonia lyase (PAL) activity, which may contribute to the resistance of A. sibiricum to locusts. There was an interaction effect between MJ treatment and endophyte infection on the growth of the host. MJ treatment was a negative regulator of the plant growth-promoting effects of endophyte infection. There was no interaction effect between MJ treatment and endophyte infection on the defense characteristics of the host. In groups not exposed to locusts, MJ treatment and endophyte infection had a similar effect in decreasing the soluble sugar content, while increasing the total phenolic content and the PAL activity. In groups exposed to locusts, the effect of MJ treatment on the above characteristics disappeared, while the effect of endophyte infection became more obvious. All of these results suggest that even for endophytes producing few alkaloids, they could still increase the resistance of native grasses to insect herbivores. Furthermore, endophyte infection might mediate the defense responses of the host, independent of jasmonic acid (JA) pathways.