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Inigo Zabalgogeazcoa - One of the best experts on this subject based on the ideXlab platform.
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A Survey of Culturable Fungal Endophytes From Festuca rubra subsp. pruinosa, a Grass From Marine Cliffs, Reveals a Core Microbiome.
Frontiers in microbiology, 2019Co-Authors: Eric Pereira, Beatriz R. Vázquez De Aldana, Leticia San Emeterio, Inigo ZabalgogeazcoaAbstract:Festuca rubra subsp. pruinosa is a perennial grass that inhabits sea cliffs of the Atlantic coasts of Europe. In this unhospitable environment plants grow in rock crevices and are exposed to abiotic stress factors such as low nutrient availability, wind, and salinity. Festuca rubra subsp. pruinosa is a host of the fungal endophyte Epichloe Festucae, which colonizes aerial organs, but its root mycobiota is unknown. The culturable endophytic mycobiota of FRP roots was surveyed in a set of 105 plants sampled at five populations in marine cliffs from the northern coast of Spain. In total, 135 different fungal taxa were identified, 17 of them occurred in more than 10% of plants and in two or more populations. Seven taxa belonging to Fusarium, Diaporthe, Helotiales, Drechslera, Slopeiomyces and Penicillium appeared to be constituents of the core microbiome of Festuca rubra subsp. pruinosa roots because they occurred in more than 20% of the plants analyzed, and at three or more populations. Most fungal strains analyzed (71.8%) were halotolerant. The presence of Epichloe Festucae in aboveground tissue was detected in 65.7 % of the plants, but its presence did not seem to significantly affect the structure of the core or other root microbiota, when compared to that of plants free of this endophyte. When plants of the grass Lolium perenne were inoculated with fungal strains obtained from Festuca rubra subsp. pruinosa roots, a Diaporthe strain significantly promoted leaf biomass production under normal and saline (200 mM NaCl) watering regimes. These results suggest that the core mycobiome of Festuca rubra subsp. pruinosa could have a role in host plant adaptation, and might be useful for the improvement of agricultural grasses.
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A Survey of Culturable Fungal Endophytes From Festuca rubra subsp. pruinosa, a Grass From Marine Cliffs, Reveals a Core Microbiome
Frontiers Media S.A., 2019Co-Authors: Eric Pereira, Beatriz Vázquez R. De Aldana, Leticia San Emeterio, Inigo ZabalgogeazcoaAbstract:Festuca rubra subsp. pruinosa is a perennial grass that inhabits sea cliffs of the Atlantic coasts of Europe. In this unhospitable environment plants grow in rock crevices and are exposed to abiotic stress factors such as low nutrient availability, wind, and salinity. Festuca rubra subsp. pruinosa is a host of the fungal endophyte Epichloë Festucae, which colonizes aerial organs, but its root mycobiota is unknown. The culturable endophytic mycobiota of FRP roots was surveyed in a set of 105 plants sampled at five populations in marine cliffs from the northern coast of Spain. In total, 135 different fungal taxa were identified, 17 of them occurred in more than 10% of plants and in two or more populations. Seven taxa belonging to Fusarium, Diaporthe, Helotiales, Drechslera, Slopeiomyces, and Penicillium appeared to be constituents of the core microbiome of Festuca rubra subsp. pruinosa roots because they occurred in more than 20% of the plants analyzed, and at three or more populations. Most fungal strains analyzed (71.8%) were halotolerant. The presence of Epichloë Festucae in aboveground tissue was detected in 65.7% of the plants, but its presence did not seem to significantly affect the structure of the core or other root microbiota, when compared to that of plants free of this endophyte. When plants of the grass Lolium perenne were inoculated with fungal strains obtained from Festuca rubra subsp. pruinosa roots, a Diaporthe strain significantly promoted leaf biomass production under normal and saline (200 mM NaCl) watering regimes. These results suggest that the core mycobiome of Festuca rubra subsp. pruinosa could have a role in host plant adaptation, and might be useful for the improvement of agricultural grasses
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Data_Sheet_1_A Survey of Culturable Fungal Endophytes From Festuca rubra subsp. pruinosa, a Grass From Marine Cliffs, Reveals a Core Microbiome.PDF
2019Co-Authors: Eric Pereira, Beatriz Vázquez R. De Aldana, Leticia San Emeterio, Inigo ZabalgogeazcoaAbstract:Festuca rubra subsp. pruinosa is a perennial grass that inhabits sea cliffs of the Atlantic coasts of Europe. In this unhospitable environment plants grow in rock crevices and are exposed to abiotic stress factors such as low nutrient availability, wind, and salinity. Festuca rubra subsp. pruinosa is a host of the fungal endophyte Epichloë Festucae, which colonizes aerial organs, but its root mycobiota is unknown. The culturable endophytic mycobiota of FRP roots was surveyed in a set of 105 plants sampled at five populations in marine cliffs from the northern coast of Spain. In total, 135 different fungal taxa were identified, 17 of them occurred in more than 10% of plants and in two or more populations. Seven taxa belonging to Fusarium, Diaporthe, Helotiales, Drechslera, Slopeiomyces, and Penicillium appeared to be constituents of the core microbiome of Festuca rubra subsp. pruinosa roots because they occurred in more than 20% of the plants analyzed, and at three or more populations. Most fungal strains analyzed (71.8%) were halotolerant. The presence of Epichloë Festucae in aboveground tissue was detected in 65.7% of the plants, but its presence did not seem to significantly affect the structure of the core or other root microbiota, when compared to that of plants free of this endophyte. When plants of the grass Lolium perenne were inoculated with fungal strains obtained from Festuca rubra subsp. pruinosa roots, a Diaporthe strain significantly promoted leaf biomass production under normal and saline (200 mM NaCl) watering regimes. These results suggest that the core mycobiome of Festuca rubra subsp. pruinosa could have a role in host plant adaptation, and might be useful for the improvement of agricultural grasses.
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Sampling sites and experimental locations.
2019Co-Authors: Päivi H. Leinonen, Inigo Zabalgogeazcoa, Marjo Helander, Beatriz R. Vázquez-de-aldana, Kari SaikkonenAbstract:Locations of the reciprocal transplantation and sampling sites of natural populations of Festuca rubra with or without symbiotic fungus Epichloë Festucae used in this study.
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Survival in the field.
2019Co-Authors: Päivi H. Leinonen, Inigo Zabalgogeazcoa, Marjo Helander, Beatriz R. Vázquez-de-aldana, Kari SaikkonenAbstract:Cumulative survival of the host plant Festuca rubra originating from four geographic regions (circles: northern Finland, triangles: Faroe Islands, squares: southern Finland, diamonds: Spain) for plants with (black) and without (grey) fungal symbiont Epichloë Festucae in a four-way reciprocal transplant experiment in their local environments in northern Finland, Faroe Islands, southern Finland and Spain. Local geographic origin at each site is indicated with a solid line. Asterisks indicate significance of likelihood ratio tests for survival at the end of the experiment between local and nonlocal genotypes (**** P < 0.0001; *** P < 0.001; ** P < 0.01; * P < 0.05; NS P > 0.05). See Table 3 for full details of results of the statistical tests.
Faith C Belanger - One of the best experts on this subject based on the ideXlab platform.
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the epichloe Festucae antifungal protein efe afpa is also a possible effector protein required for the interaction of the fungus with its host grass Festuca rubra subsp rubra
Microorganisms, 2021Co-Authors: Ruying Wang, Bruce B Clarke, Simin Luo, Faith C BelangerAbstract:Strong creeping red fescue (Festuca rubra subsp. rubra) is a commercially important low-maintenance turfgrass and is often naturally infected with the fungal endophyte EpichloeFestucae. Epichloe spp. are endophytes of several cool-season grass species, often conferring insect resistance to the grass hosts due to the production of toxic alkaloids. In addition to insect resistance, a unique feature of the strong creeping red fescue/E. Festucae symbiosis is the endophyte-mediated disease resistance to the fungal pathogen Clarireedia jacksonii, the causal agent of dollar spot disease. Such disease resistance is not a general feature of other grass/ Epichloe interactions. E. Festucae isolates infecting red fescue have an antifungal protein gene Efe-afpA, whereas most other Epichloe spp. do not have a similar gene. The uniqueness of this gene suggests it may, therefore, be a component of the unique disease resistance seen in endophyte-infected red fescue. Here, we report the generation of CRISPR-Cas9 Efe-afpA gene knockouts with the goal of determining if absence of the protein in endophyte-infected Festuca rubra leads to disease susceptibility. However, it was not possible to infect plants with the knockout isolates, although infection was possible with the wild type E. Festucae and with complemented isolates. This raises the interesting possibility that, in addition to having antifungal activity, the protein is required for the symbiotic interaction. The antifungal protein is a small secreted protein with high expression in planta relative to its expression in culture, all characteristics consistent with effector proteins. If Efe-AfpA is an effector protein it must be specific to certain interactions, since most Epichloe spp. do not have such a gene in their genomes.
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transcriptome analysis of choke stroma and asymptomatic inflorescence tissues reveals changes in gene expression in both epichloe Festucae and its host plant Festuca rubra subsp rubra
Microorganisms, 2019Co-Authors: Ruying Wang, Bruce B Clarke, Faith C BelangerAbstract:Many cool-season grasses have symbiotic relationships with Epichloe (Ascomycota, Clavicipitaceae) fungal endophytes that inhabit the intercellular spaces of the above-ground parts of the host plants. The presence of the Epichloe endophytes is generally beneficial to the hosts due to enhanced tolerance to biotic and abiotic stresses conferred by the endophytes. Many Epichloe spp. are asexual, and those infections always remain asymptomatic. However, some Epichloe spp. have a sexual stage and produce a macroscopic fruiting body, a stroma, that envelops the developing inflorescence causing a syndrome termed “choke disease”. Here, we report a fungal and plant gene expression analysis of choke stroma tissue and asymptomatic inflorescence tissue of Epichloe Festucae-infected strong creeping red fescue (Festuca rubra subsp. rubra). Hundreds of fungal genes and over 10% of the plant genes were differentially expressed when comparing the two tissue types. The differentially expressed fungal genes in the choke stroma tissue indicated a change in carbohydrate and lipid metabolism, as well as a change in expression of numerous genes for candidate effector proteins. Plant stress-related genes were up-regulated in the stroma tissue, suggesting the plant host was responding to the epiphytic stage of E. Festucae as a pathogen.
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transcriptome analysis of choke stroma and asymptomatic inflorescence tissues reveals changes in gene expression in both epichloe Festucae and its host plant Festuca rubra subsp rubra
Microorganisms, 2019Co-Authors: Ruying Wang, Bruce B Clarke, Faith C BelangerAbstract:Many cool-season grasses have symbiotic relationships with Epichloe (Ascomycota, Clavicipitaceae) fungal endophytes that inhabit the intercellular spaces of the above-ground parts of the host plants. The presence of the Epichloe endophytes is generally beneficial to the hosts due to enhanced tolerance to biotic and abiotic stresses conferred by the endophytes. Many Epichloe spp. are asexual, and those infections always remain asymptomatic. However, some Epichloe spp. have a sexual stage and produce a macroscopic fruiting body, a stroma, that envelops the developing inflorescence causing a syndrome termed “choke disease”. Here, we report a fungal and plant gene expression analysis of choke stroma tissue and asymptomatic inflorescence tissue of Epichloe Festucae-infected strong creeping red fescue (Festuca rubra subsp. rubra). Hundreds of fungal genes and over 10% of the plant genes were differentially expressed when comparing the two tissue types. The differentially expressed fungal genes in the choke stroma tissue indicated a change in carbohydrate and lipid metabolism, as well as a change in expression of numerous genes for candidate effector proteins. Plant stress-related genes were up-regulated in the stroma tissue, suggesting the plant host was responding to the epiphytic stage of E. Festucae as a pathogen.
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the epichloe Festucae antifungal protein has activity against the plant pathogen sclerotinia homoeocarpa the causal agent of dollar spot disease
Scientific Reports, 2017Co-Authors: Zipeng Tian, Ruying Wang, Karen V Ambrose, Bruce B Clarke, Faith C BelangerAbstract:Epichloe spp. are naturally occurring fungal endophytic symbionts of many cool-season grasses. Infection by the fungal endophytes often confers biotic and abiotic stress tolerance to their hosts. Endophyte-mediated disease resistance is well-established in the fine fescue grass Festuca rubra subsp. rubra (strong creeping red fescue) infected with E. Festucae. Resistance to fungal pathogens is not an established effect of endophyte infection of other grass species, and may therefore be unique to the fine fescues. The underlying mechanism of the disease resistance is unknown. E. Festucae produces a secreted antifungal protein that is highly expressed in the infected plant tissues and may therefore be involved in the disease resistance. Most Epichloe spp. do not have a gene for a similar antifungal protein. Here we report the characterization of the E. Festucae antifungal protein, designated Efe-AfpA. The antifungal protein partially purified from the apoplastic proteins of endophyte-infected plant tissue and the recombinant protein expressed in the yeast Pichia pastoris was found to have activity against the important plant pathogen Sclerotinia homoeocarpa. Efe-AfpA may therefore be a component of the disease resistance seen in endophyte-infected strong creeping red fescue.
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functional characterization of salicylate hydroxylase from the fungal endophyte epichloe Festucae
Scientific Reports, 2015Co-Authors: Karen V Ambrose, Zipeng Tian, Yifei Wang, Jordan Smith, Gerben J Zylstra, Bingru Huang, Faith C BelangerAbstract:Epichloe spp. are symbiotic fungal endophytes of many cool season grasses. The presence of the fungal endophytes often confers insect, drought, and disease tolerance to the host grasses. The presence of the fungal endophytes within the host plants does not elicit host defense responses. The molecular basis for this phenomenon is not known. Epichloe Festucae, the endophyte of Festuca rubra, expresses a salicylate hydroxylase similar to NahG from the bacterium Pseudomonas putida. Few fungal salicylate hydroxylase enzymes have been reported. The in planta expression of an endophyte salicylate hydroxylase raised the possibility that degradation of plant-produced salicylic acid is a factor in the mechanism of how the endophyte avoids eliciting host plant defenses. Here we report the characterization of the E. Festucae salicylate hydroxylase, designated Efe-shyA. Although the fungal enzyme has the expected activity, based on salicylic acid levels in endophyte-free and endophyte-infected plants it is unlikely that expression of the endophyte salicylate hydroxylase is a factor in the lack of a host defense response to the presence of the fungal endophyte.
Z Zwierzykowski - One of the best experts on this subject based on the ideXlab platform.
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cytogenetic and molecular genotyping in the allotetraploid Festuca pratensis lolium perenne hybrids
BMC Genomics, 2019Co-Authors: Joanna Majka, Katarzyna Bzdega, Agnieszka Janiak, Hanna Cwiekkupczynska, Tomasz Książczyk, Pawel Krajewski, Z ZwierzykowskiAbstract:Species of the Festuca and Lolium genera, as well as intergeneric Festuca × Lolium (Festulolium) hybrids, are valuable fodder and turf grasses for agricultural and amenity purposes worldwide. Festulolium hybrids can merge in their genomes agronomically important characteristics. However, in polyploid plants, especially in allopolyploids, the hybridization of divergent genomes could contribute to various abnormalities, such as variability in chromosome number, structural rearrangements, and/or disorders in inheritance patterns. Here we studied these issues in allotetraploid Festuca pratensis × Lolium perenne hybrids. Cytogenetic procedures, including fluorescent in situ hybridization, genomic in situ hybridization, and molecular markers – inter-simple sequence repeats (ISSR) were exploited. This cytogenetic approach indicated the dynamics in the number and distribution of ribosomal RNA genes and structural rearrangements for both parental genomes (Festuca and Lolium) in hybrid karyotypes. The separate analysis of F. pratensis and L. perenne chromosomes in hybrid plants (F2-F3 generations of F. pratensis × L. perenne) revealed the asymmetrical level of rearrangements. Recognized structural changes were mainly located in the distal part of chromosome arms, and in chromosomes bearing ribosomal DNA, they were more frequently mapped in arms without this sequence. Based on the ISSR markers distribution, we found that the tetrasomic type of inheritance was characteristic for the majority of ISSR loci, but the disomic type was also observed. Nonetheless, no preference in the transmission of either Festuca or Lolium alleles to the following generations of allotetraploid F. pratensis × L. perenne hybrid was observed. Our study reports cytogenetic and molecular genotyping of the F. pratensis × L. perenne hybrid and its following F2-F3 progenies. The analysis of 137 allotetraploid F. pratensis × L. perenne hybrids revealed the higher level of recombination in chromosomes derived from F. pratensis genome. The results of ISSR markers indicated a mixed model of inheritance, which may be characteristic for these hybrids.
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genome constitution in selected and unselected plants of f 2 f 4 generations derived from an allotetraploid Festuca pratensis lolium perenne hybrid
2013Co-Authors: Z Zwierzykowski, Elŝbieta Zwierzykowska, Neil D Jones, Tomasz Ksiązczyk, Magdalena Taciak, Arkadiusz KosmalaAbstract:The objective of this work was to assess the genomic constitution and intergeneric recombination in three successive unselected generations, (F2–F4), derived from an intergeneric hybrid between Festuca pratensis Huds. (2n = 4x = 28) and Lolium perenne L. (2n = 4x = 28). Examination based on genomic in situ hybridization analyses of randomly chosen plants in each generation indicated progressive changes in genome balance towards that of Lolium. The dominance of Lolium chromatin over Festuca likely resulted from extensive recombination between chromosomes of the parental genomes, together with substitutions of whole Festuca chromosomes by whole Lolium chromosomes. The total number of Lolium chromosomes increased from generation to generation. The number of recombinant chromosomes, and recombination breakpoints per genotype, also increased in successive generations, but their number was higher for Festuca than for Lolium. The patterns of genome constitutions and recombination were similar to those we observed in selected generations (F2–F4 breeding populations) developed from the same F1 hybrid plants.
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genome balance in six successive generations of the allotetraploid Festuca pratensis lolium perenne
Theoretical and Applied Genetics, 2006Co-Authors: Z Zwierzykowski, Arkadiusz Kosmala, Elŝbieta Zwierzykowska, Wojciech Cieślik, Neil D Jones, Jan BocianowskiAbstract:In the allotetraploid, Festuca pratensis Huds. (2n = 4x = 28) × Lolium perenne L. (2n = 4x = 28) the balance of chromatin, as determined by GISH, changes over successive generations of open pollination in favour of L. perenne. There is extensive recombination between chromosomes of the two parental genomes, as well as substitution of whole Festuca chromosomes by whole Lolium chromosomes. The total number of Lolium chromosomes increased from a mean 14.36 in the F2 to 16.26 in the F6, and the total number of Festuca chromosomes decreased correspondingly from a mean of 13.57 to a value of 11.56. The number of recombinant chromosomes and recombination breakpoints per genotype also increased from generation to generation, although the respective values of both characters were higher for Festuca (0.86–8.41 and 1.14–15.22) than for Lolium (0.68–4.59 and 0.68–6.0). The proportion of total genome length contributed by the L. perenne chromatin increased from about 50% in F2 to 59.5% in F6. The results are based on the sample of 134 plants studied (26–28 plants per generation), and are discussed in terms of the dominance of Lolium chromosomes over those of Festuca, and possible mechanisms underlying this phenomenon of chromatin substitution.
Kari Saikkonen - One of the best experts on this subject based on the ideXlab platform.
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postglacial colonization history reflects in the genetic structure of natural populations of Festuca rubra in europe
Ecology and Evolution, 2019Co-Authors: Päivi H. Leinonen, Marjo Helander, Maria Von Crautlein, Helena Korpelainen, Henry Vare, Kari SaikkonenAbstract:We conducted a large-scale population genetic survey of genetic diversity of the host grass Festuca rubra s.l., which fitness can be highly dependent on its symbiotic fungus Epichloe Festucae, to evaluate genetic variation and population structure across the European range. The 27 studied populations have previously been found to differ in frequencies of occurrence of the symbiotic fungus E. Festucae and ploidy levels. As predicted, we found decreased genetic diversity in previously glaciated areas in comparison with nonglaciated regions and discovered three major maternal genetic groups: southern, northeastern, and northwestern Europe. Interestingly, host populations from Greenland were genetically similar to those from the Faroe Islands and Iceland, suggesting gene flow also between those areas. The level of variation among populations within regions is evidently highly dependent on the postglacial colonization history, in particular on the number of independent long-distance seed colonization events. Yet, also anthropogenic effects may have affected the population structure in F. rubra. We did not observe higher fungal infection rates in grass populations with lower levels of genetic variability. In fact, the fungal infection rates of E. Festucae in relation to genetic variability of the host populations varied widely among geographical areas, which indicate differences in population histories due to colonization events and possible costs of systemic fungi in harsh environmental conditions. We found that the plants of different ploidy levels are genetically closely related within geographic areas indicating independent formation of polyploids in different maternal lineages.
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Sampling sites and experimental locations.
2019Co-Authors: Päivi H. Leinonen, Inigo Zabalgogeazcoa, Marjo Helander, Beatriz R. Vázquez-de-aldana, Kari SaikkonenAbstract:Locations of the reciprocal transplantation and sampling sites of natural populations of Festuca rubra with or without symbiotic fungus Epichloë Festucae used in this study.
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Survival in the field.
2019Co-Authors: Päivi H. Leinonen, Inigo Zabalgogeazcoa, Marjo Helander, Beatriz R. Vázquez-de-aldana, Kari SaikkonenAbstract:Cumulative survival of the host plant Festuca rubra originating from four geographic regions (circles: northern Finland, triangles: Faroe Islands, squares: southern Finland, diamonds: Spain) for plants with (black) and without (grey) fungal symbiont Epichloë Festucae in a four-way reciprocal transplant experiment in their local environments in northern Finland, Faroe Islands, southern Finland and Spain. Local geographic origin at each site is indicated with a solid line. Asterisks indicate significance of likelihood ratio tests for survival at the end of the experiment between local and nonlocal genotypes (**** P < 0.0001; *** P < 0.001; ** P < 0.01; * P < 0.05; NS P > 0.05). See Table 3 for full details of results of the statistical tests.
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non systemic fungal endophytes in Festuca rubra plants infected by epichloe Festucae in subarctic habitats
Fungal Diversity, 2013Co-Authors: Inigo Zabalgogeazcoa, Marjo Helander, Pedro E Gundel, Kari SaikkonenAbstract:Epichloe Festucae is an endophytic fungus that infects systemically the aerial tissues of the host grass Festuca rubra. This fungus is transmitted vertically from the mother plant to seeds. Hypothetically, the presence of E. Festucae could affect the infection of a plant by other fungal species. This could occur if E. Festucae metabolites produced in planta interfere negatively with other fungal infections; or alternatively, if the modulation of plant defenses by the endophyte favour further fungal infections. We have analyzed the presence of culturable non-systemic endophytes in plants of F. rubra infected (E+) and not infected (E−) by E. Festucae in two subarctic habitats, meadows and riverbanks in Northern Finland. The observed non-systemic endophyte infection frequencies were similar among E+ and E− plants from riverbanks, and E+ plants from meadows. In contrast to these, the infection frequency was significantly lower in E− plants from meadows. This result suggests that the presence of E. Festucae is not a main factor determining the presence of non-systemic endophytes in plants. Instead, plant genetic characteristics related to compatibility with E. Festucae and other endophytes in the more stable meadow populations might play a role in these fungus–fungus–plant interactions. As a result of the survey, 18 different taxa of non-systemic endophytes were identified in plants of F. rubra. All were ascomycetes except for one basidiomycete. Three endophytic taxa could not be ascribed to a genus, but sequence data indicated that they were conspecific with other unidentified endophytes that have been isolated in cold biomes at different locations.
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antioxidants in Festuca rubra l seeds affected by the fungal symbiont epichloe Festucae
Symbiosis, 2012Co-Authors: Pedro E Gundel, Inigo Zabalgogeazcoa, Beatriz Vázquez R. De Aldana, Marjo Helander, Cyd E Hamilton, Charlotte E Seal, M A Martinezghersa, Claudio M Ghersa, Kari SaikkonenAbstract:Vertically transmitted fungal endophytes can be beneficial for host grasses. While the alkaloid-mediated mechanism for herbivore resistance has been widely studied, underlying physiological mechanisms for increased tolerance to abiotic stress remain scarcely explored. In this study we used three maternal lines of perennial grass Festuca rubra to examine the role of antioxidants in endophyte-mediated effects on seed viability over long-term storage. Uncolonized plants (E−) were generated by removing the endophyte from ramets of naturally endophyte-colonized (E+) plants. The E + and E− ramets were planted in a common garden in Salamanca, Spain. Seeds produced in 2009, 2010 and 2011 were harvested at maturity, dried and stored at 10 °C until 2011 when we tested seed and endophyte viability, and measured antioxidants. Seed viability and α-tocopherol antioxidant were negatively affected by the endophyte in two maternal lines. In these same lines, the endophyte viability was lowest at the longest storage time. In the maternal line that showed the highest negative effect of endophyte on seed viability, the pattern of glutathione was opposite to that observed for tocopherols since it was higher for E + than for E− seeds. In all maternal lines, the glutathione half-cell reduction potential (EGSSG/2GSH) and % glutathione disulphide (GSSG) increased with storage time but there was no clear pattern associated with endophyte symbiosis. Whether these parameters are good predictors of seed and endophyte longevity in storage and natural conditions should be further explored.
Karen V Ambrose - One of the best experts on this subject based on the ideXlab platform.
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the epichloe Festucae antifungal protein has activity against the plant pathogen sclerotinia homoeocarpa the causal agent of dollar spot disease
Scientific Reports, 2017Co-Authors: Zipeng Tian, Ruying Wang, Karen V Ambrose, Bruce B Clarke, Faith C BelangerAbstract:Epichloe spp. are naturally occurring fungal endophytic symbionts of many cool-season grasses. Infection by the fungal endophytes often confers biotic and abiotic stress tolerance to their hosts. Endophyte-mediated disease resistance is well-established in the fine fescue grass Festuca rubra subsp. rubra (strong creeping red fescue) infected with E. Festucae. Resistance to fungal pathogens is not an established effect of endophyte infection of other grass species, and may therefore be unique to the fine fescues. The underlying mechanism of the disease resistance is unknown. E. Festucae produces a secreted antifungal protein that is highly expressed in the infected plant tissues and may therefore be involved in the disease resistance. Most Epichloe spp. do not have a gene for a similar antifungal protein. Here we report the characterization of the E. Festucae antifungal protein, designated Efe-AfpA. The antifungal protein partially purified from the apoplastic proteins of endophyte-infected plant tissue and the recombinant protein expressed in the yeast Pichia pastoris was found to have activity against the important plant pathogen Sclerotinia homoeocarpa. Efe-AfpA may therefore be a component of the disease resistance seen in endophyte-infected strong creeping red fescue.
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functional characterization of salicylate hydroxylase from the fungal endophyte epichloe Festucae
Scientific Reports, 2015Co-Authors: Karen V Ambrose, Zipeng Tian, Yifei Wang, Jordan Smith, Gerben J Zylstra, Bingru Huang, Faith C BelangerAbstract:Epichloe spp. are symbiotic fungal endophytes of many cool season grasses. The presence of the fungal endophytes often confers insect, drought, and disease tolerance to the host grasses. The presence of the fungal endophytes within the host plants does not elicit host defense responses. The molecular basis for this phenomenon is not known. Epichloe Festucae, the endophyte of Festuca rubra, expresses a salicylate hydroxylase similar to NahG from the bacterium Pseudomonas putida. Few fungal salicylate hydroxylase enzymes have been reported. The in planta expression of an endophyte salicylate hydroxylase raised the possibility that degradation of plant-produced salicylic acid is a factor in the mechanism of how the endophyte avoids eliciting host plant defenses. Here we report the characterization of the E. Festucae salicylate hydroxylase, designated Efe-shyA. Although the fungal enzyme has the expected activity, based on salicylic acid levels in endophyte-free and endophyte-infected plants it is unlikely that expression of the endophyte salicylate hydroxylase is a factor in the lack of a host defense response to the presence of the fungal endophyte.
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solid sage of endophyte infected red fescue reveals numerous effects on host transcriptome and an abundance of highly expressed fungal secreted proteins
PLOS ONE, 2012Co-Authors: Karen V Ambrose, Faith C BelangerAbstract:One of the most important plant-fungal symbiotic relationships is that of cool season grasses with endophytic fungi of the genera Epichloe and Neotyphodium. These associations often confer benefits, such as resistance to herbivores and improved drought tolerance, to the hosts. One benefit that appears to be unique to fine fescue grasses is disease resistance. As a first step towards understanding the basis of the endophyte-mediated disease resistance in Festuca rubra we carried out a SOLiD-SAGE quantitative transcriptome comparison of endophyte-free and Epichloe Festucae-infected F. rubra. Over 200 plant genes involved in a wide variety of physiological processes were statistically significantly differentially expressed between the two samples. Many of the endophyte expressed genes were surprisingly abundant, with the most abundant fungal tag representing over 10% of the fungal mapped tags. Many of the abundant fungal tags were for secreted proteins. The second most abundantly expressed fungal gene was for a secreted antifungal protein and is of particular interest regarding the endophyte-mediated disease resistance. Similar genes in Penicillium and Aspergillus spp. have been demonstrated to have antifungal activity. Of the 10 epichloae whole genome sequences available, only one isolate of E. Festucae and Neotyphodium gansuense var inebrians have an antifungal protein gene. The uniqueness of this gene in E. Festucae from F. rubra, its transcript abundance, and the secreted nature of the protein, all suggest it may be involved in the disease resistance conferred to the host, which is a unique feature of the fine fescue–endophyte symbiosis.
