Browse
Submit Data
Databases
API
Help

Dataset Information

33 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Functional characterization of salicylate hydroxylase from the fungal endophyte Epichloe festucae.

ABSTRACT: Epichloë 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. Epichloë 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.

SUBMITTER: Ambrose KV

PROVIDER: S-EPMC4460724 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Fungal endophyte (Epichloe festucae) alters the nutrient content of Festuca rubra regardless of water availability.

Project description:Festuca rubra plants maintain associations with the vertically transmitted fungal endophyte Epichloë festucae. A high prevalence of infected host plants in semiarid grasslands suggests that this association could be mutualistic. We investigated if the Epichloë-endophyte affects the growth and nutrient content of F. rubra plants subjected to drought. Endophyte-infected (E+) and non-infected (E-) plants of two half-sib lines (PEN and RAB) were subjected to three water availability treatments. Shoot and root biomass, nutrient content, proline, phenolic compounds and fungal alkaloids were measured after the treatments. The effect of the endophyte on shoot and root biomass and dead leaves depended on the plant line. In the PEN line, E+ plants had a greater S:R ratio than E-, but the opposite occurred in RAB. In both plant lines and all water treatments, endophyte-infected plants had greater concentrations of N, P and Zn in shoots and Ca, Mg and Zn in roots than E- plants. On average, E+ plants contained in their shoots more P (62%), Zn (58%) and N (19%) than E- plants. While the proline in shoots increased in response to water stress, the endophyte did not affect this response. A multivariate analysis showed that endophyte status and plant line impose stronger differences in the performance of the plants than the water stress treatments. Furthermore, differences between PEN and RAB lines seemed to be greater in E- than in E+ plants, suggesting that E+ plants of both lines are more similar than those of their non-infected version. This is probably due to the endophyte producing a similar effect in both plant lines, such as the increase in N, P and Zn in shoots. The remarkable effect of the endophyte in the nutrient balance of the plants could help to explain the high prevalence of infected plants in natural grasslands.

| S-EPMC3867530 | biostudies-literature

Deletion of the fungal gene soft disrupts mutualistic symbiosis between the grass endophyte Epichloe festucae and the host plant.

Project description:Hyphal anastomosis, or vegetative hyphal fusion, establishes the interconnection of individual hyphal strands into an integrated network of a fungal mycelium. In contrast to recent advances in the understanding of the molecular basis for hyphal anastomosis, knowledge of the physiological role of hyphal anastomosis in the natural habitats of filamentous fungi is still very limited. To investigate the role of hyphal anastomosis in fungal endophyte-plant interactions, we generated mutant strains lacking the Epichloë festucae soft (so) gene, an ortholog of the hyphal anastomosis gene so in the endophytic fungus E. festucae. The E. festucae ?so mutant strains grew similarly to the wild-type strain in culture but with reduced aerial hyphae and completely lacked hyphal anastomosis. The most striking phenotype of the E. festucae ?so mutant strain was that it failed to establish a mutualistic symbiosis with the tall fescue plant host (Lolium arundinaceum); instead, it killed the host plant within 2 months after the initial infection. Microscopic examination revealed that the death of the tall fescue plant host was associated with the distortion and disorganization of plant cells. This study suggests that hyphal anastomosis may have an important role in the establishment/maintenance of fungal endophyte-host plant mutualistic symbiosis.

| S-EPMC3536286 | biostudies-literature

Comparison of Plant Metabolites in Root Exudates of Lolium perenne Infected with Different Strains of the Fungal Endophyte Epichloe festucae var. lolii.

Project description:Lolium perenne infected with the fungal endophyte Epichloë festucae var. lolii have specific, endophyte strain-dependent, chemical phenotypes in their above-ground tissues. Differences in these chemical phenotypes have been largely associated with classes of fungal-derived alkaloids which protect the plant against many insect pests. However, the use of new methodologies, such as various omic techniques, has demonstrated that many other chemical changes occur in both primary and secondary metabolites. Few studies have investigated changes in plant metabolites exiting the plant in the form of root exudates. As root exudates play an essential role in the acquisition of nutrients, microbial associations, and defense in the below-ground environment, it is of interest to understand how plant root exudate chemistry is influenced by the presence of strains of a fungal endophyte. In this study, we tested the influence of four strains of E. festucae var. lolii (E+ (also known as Lp19), AR1, AR37, NEA2), and uninfected controls (E-), on L. perenne growth and the composition of root exudate metabolites. Root exudates present in the hydroponic water were assessed by untargeted metabolomics using Accurate-Mass Quadrupole Time-of-Flight (Q-TOF) liquid chromatography-mass spectrometry (LC-MS). The NEA2 endophyte strain resulted in the greatest plant biomass and the lowest endophyte concentration. We found 84 metabolites that were differentially expressed in at least one of the endophyte treatments compared to E- plants. Two compounds were strongly associated with one endophyte treatment, one in AR37 (m/z 135.0546 RT 1.17), and one in E+ (m/z 517.1987 RT 9.26). These results provide evidence for important changes in L. perenne physiology in the presence of different fungal endophyte strains. Further research should aim to connect changes in root exudate chemical composition with soil ecosystem processes.

| S-EPMC7922862 | biostudies-literature

<i>Epichloe</i> Increases Root Fungal Endophyte Richness and Alters Root Fungal Endophyte Composition in a Changing World.

Project description:Plants harbor a variety of fungal symbionts both above- and belowground, yet little is known about how these fungi interact within hosts, especially in a world where resource availability is changing due to human activities. Systemic vertically transmitted endophytes such as Epichloë spp. may have particularly strong effects on the diversity and composition of later-colonizing symbionts such as root fungal endophytes, especially in primary successional systems. We made use of a long-term field experiment in Great Lakes sand dunes to test whether Epichloë colonization of the dune-building grass, Ammophila breviligulata, could alter fungal root endophyte species richness or community composition in host plants. We also tested whether nitrogen addition intensified the effects of Epichlöe on the root endophyte community. We found that Epichloë increased richness of root endophytes in Ammophila by 17% overall, but only shifted community composition of root endophytes under nitrogen-enriched conditions. These results indicate that Epichlöe acts as a key species within Ammophila, changing richness and composition of the root mycobiome and integrating above- and belowground mycobiome interactions. Further, effects of Epichloë on root endophyte communities were enhanced by N addition, indicating that this fungal species may become even more important in future environments.

| S-EPMC9697489 | biostudies-literature

Effects of the Fungal Endophyte Epichloe festucae var. lolii on Growth and Physiological Responses of Perennial Ryegrass cv. Fairway to Combined Drought and Pathogen Stresses.

Project description:Perennial ryegrass (Lolium perenne) is widely cultivated around the world for turf and forage. However, the plant is highly susceptible to disease and is sensitive to drought. The present study aims to determine the effect of the fungal endophyte Epichloë festucae var. lolii of perennial ryegrass on the combined stresses of drought and disease caused by Bipolaris sorokiniana in the greenhouse. In the experiment, plants infected (E+) or not infected (E-) with the fungal endophyte were inoculated with Bipolaris sorokiniana and put under different soil water regimes (30%, 50%, and 70%). The control treatment consisted of E+ and E- plants not inoculated with B. sorokiniana. Plant growth, phosphorus (P) uptake, photosynthetic parameters, and other physiological indices were evaluated two weeks after pathogen infection. The fungal endophyte in E+ plants increased P uptake, plant growth, and photosynthetic parameters but decreased the malondialdehyde concentration, proline content, and disease incidence of perennial ryegrass (p < 0.05). E+ plants had the lowest disease incidence at 70% soil water (p < 0.05). The study demonstrates that the fungal endophyte E. festucae var. lolii is beneficial for plant growth and stress tolerance in perennial ryegrass exposed to the combined stresses of drought and B. sorokiniana.

| S-EPMC7760724 | biostudies-literature

Redox regulation of an AP-1-like transcription factor, YapA, in the fungal symbiont Epichloe festucae.

Project description:One of the central regulators of oxidative stress in Saccharomyces cerevisiae is Yap1, a bZIP transcription factor of the AP-1 family. In unstressed cells, Yap1 is reduced and cytoplasmic, but in response to oxidative stress, it becomes oxidized and accumulates in the nucleus. To date, there have been no reports on the role of AP-1-like transcription factors in symbiotic fungi. An ortholog of Yap1, named YapA, was identified in the genome of the grass symbiont Epichloë festucae and shown to complement an S. cerevisiae ?yap1 mutant. Hyphae of the E. festucae ?yapA strain were sensitive to menadione and diamide but resistant to H2O2, KO2, and tert-butyl hydroperoxide (t-BOOH). In contrast, conidia of the ?yapA strain were very sensitive to H2O2 and failed to germinate. Using a PcatA-eGFP degron-tagged reporter, YapA was shown to be required for expression of a spore-specific catalase gene, catA. Although YapA-EGFP localized to the nucleus in response to host reactive oxygen species during seedling infection, there was no difference in whole-plant and cellular phenotypes of plants infected with the ?yapA strain compared to the wild-type strain. Homologs of the S. cerevisiae and Schizosaccharomyces pombe redox-sensing proteins (Gpx3 and Tpx1, respectively) did not act as redox sensors for YapA in E. festucae. In response to oxidative stress, YapA-EGFP localized to the nuclei of E. festucae ?gpxC, ?tpxA, and ?gpxC ?tpxA cells to the same degree as that in wild-type cells. These results show that E. festucae has a robust system for countering oxidative stress in culture and in planta but that Gpx3- or Tpx1-like thiol peroxidases are dispensable for activation of YapA.

| S-EPMC3811341 | biostudies-literature

Fungal Endophyte Colonization Patterns Alter Over Time in the Novel Association Between Lolium perenne and Epichloe Endophyte AR37.

Project description:Infection of the pasture grass Lolium perenne with the seed-transmitted fungal endophyte Epichloë festucae enhances its resilience to biotic and abiotic stress. Agricultural benefits of endophyte infection can be increased by generating novel symbiotic associations through inoculating L. perenne with selected Epichloë strains. Natural symbioses have coevolved over long periods. Thus, artificial symbioses will probably not have static properties, but symbionts will coadapt over time improving the fitness of the association. Here we report for the first time on temporal changes in a novel association of Epichloë strain AR37 and the L. perenne cultivar Grasslands Samson. Over nine generations, a seed maintenance program had increased the endophyte seed transmission rates to > 95% (from an initial 76%). We observed an approximately fivefold decline in endophyte biomass concentration in vegetative tissues over time (between generations 2 and 9). This indicates strong selection pressure toward reducing endophyte-related fitness costs by reducing endophyte biomass, without compromising the frequency of endophyte transmission to seed. We observed no obvious changes in tillering and only minor transcriptomic changes in infected plants over time. Functional analysis of 40 plant genes, showing continuously decreasing expression over time, suggests that adaptation of host metabolism and defense mechanisms are important for increasing the fitness of this association, and possibly fitness of such symbioses in general. Our results indicate that fitness of novel associations is likely to improve over time and that monitoring changes in novel associations can assist in identifying key features of endophyte-mediated enhancement of host fitness.

| S-EPMC7658011 | biostudies-literature

Development and characterization of nuclear microsatellite markers in the endophytic fungus Epichloe festucae (Clavicipitaceae).

Project description:Microsatellite primers were developed for the endophytic fungus Epichloë festucae, which is symbiotic with Festuca rubra, to study the population genetics of the species and to compare population structures between E. festucae and its host F. rubra. • We developed 14 polymorphic markers using the unplaced genomic scaffold sequences of E. festucae from GenBank. The number of alleles per locus (A) varied from four to 16, and unbiased haploid diversity (h) was 0.717 in eight populations located in the Faroe Islands, Finland, and Spain. The Spanish populations possessed a higher number of alleles and haploid diversity (on average A = 5.1 and h = 0.591, respectively) compared to northern populations (on average A = 1.5 and h = 0.199, respectively). • These polymorphic markers will be used by grass breeders for uses including the improvement of commercial turfgrass cultivars, and by population geneticists to study different species of the Epichloë genus.

| S-EPMC4259458 | biostudies-literature

Identification of extracellular siderophores and a related peptide from the endophytic fungus Epichloe festucae in culture and endophyte-infected Lolium perenne.

Project description:A number of genes encoding non-ribosomal peptide synthetases (NRPSs) have been identified in fungi of Epichloë/Neotyphodium species, endophytes of Pooid grasses, including sidN, putatively encoding a ferrichrome siderophore-synthesizing NRPS. Targeted gene replacement and complementation of sidN in Epichloë festucae has established that extracellular siderophore epichloënin A is the major product of the SidN enzyme complex (Johnson et al., 2007a). We report here high resolution mass spectrometric fragmentation experiments and NMR analysis of an isolated fraction establishing that epichloënin A is a siderophore of the ferrichrome family, comprising a cyclic sequence of four glycines, a glutamine and three N(?)-trans-anhydromevalonyl-N(?)-hydroxyornithine (AMHO) moieties. Epichloënin A is unusual among ferrichrome siderophores in comprising an octapeptide rather than hexapeptide sequence, and in incorporating a glutamine residue. During this investigation we have established that desferrichrome siderophores with pendant trans-AMHO groups can be distinguished from those with pendant cis-AMHO groups by the characteristic neutral loss of an hydroxyornithine moiety in the MS/MS spectrum. A minor component, epichloënin B, has been characterized as the triglycine variant by mass spectrometry. A peptide characterized by mass spectrometry as the putative deoxygenation product, epichloëamide has been detected together with ferriepichloënin A in guttation fluid from ryegrass (Lolium perenne) plants infected with wild-type E. festucae, but not in plants infected with the ?sidN mutant strain, and also detected at trace levels in wild-type E. festucae fungal culture.

| S-EPMC3311397 | biostudies-literature