Signalling in the Epichloë festucae: Perennial Ryegrass Mutualistic Symbiotic Interaction

Eaton, Carla J.; Mitić, Milena; Scott, Barry

doi:10.1007/978-3-642-20966-6_7

Cited by 6 publications

(4 citation statements)

References 175 publications

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“…To date, there have been no reports on the role of AP-1-like transcription factors in fungus-plant symbiotic interactions, such as the mutualistic symbiotic interaction between the fungus Epichloë festucae (Ascomycota, Clavicipitaceae) and the plant Lolium perenne (36,37). This biotrophic fungus systemically colonizes the vegetative and reproductive aerial tissues but not the roots of the plant.…”

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confidence: 99%

Redox Regulation of an AP-1-Like Transcription Factor, YapA, in the Fungal Symbiont Epichloë festucae

Cartwright

Scott

2013

Eukaryot Cell

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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 H 2 O 2 , KO 2 , and tert-butyl hydroperoxide (t-BOOH). In contrast, conidia of the ⌬yapA strain were very sensitive to H 2 O 2 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.

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confidence: 99%

Redox Regulation of an AP-1-Like Transcription Factor, YapA, in the Fungal Symbiont Epichloë festucae

Cartwright

Scott

2013

Eukaryot Cell

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“…The bar corresponds to 5 mm. tomless symbiosis is the restricted intercellular growth of endophytes, which is synchronized to host plant growth (5,8,37). In support of this view, all E. festucae mutant isolates studied so far that stunt host plants showed increased endophytic biomass due to presumably unrestricted growth in planta (39)(40)(41)(42).…”

Section: Real-time Quantitative Pcr For Fungal Biomass Analysismentioning

confidence: 76%

Deletion of the Fungal Gene soft Disrupts Mutualistic Symbiosis between the Grass Endophyte Epichloë festucae and the Host Plant

et al. 2012

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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.

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“…One DEG involved in calcium signaling was 5-fold overexpressed in LT>HT genotypes within the OV samples. Calcium-dependent secondary messenger signaling is a major pathway for signal transduction perceived by cell surface receptors such as Gprotein coupled receptors and histidine kinases (Eaton et al, 2012). The two most important hormonal signaling pathways associated with induced plant defenses are the jasmonic acid and salicylic acid pathways.…”

Section: Discussionmentioning

confidence: 99%

Epichloë seed transmission efficiency is influenced by plant defense response mechanisms

et al. 2022

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Asexual Epichloë are endophytic fungi that form mutualistic symbioses with cool-season grasses, conferring to their hosts protection against biotic and abiotic stresses. Symbioses are maintained between grass generations as hyphae are vertically transmitted from parent to progeny plants through seed. However, endophyte transmission to the seed is an imperfect process where not all seeds become infected. The mechanisms underpinning the varying efficiencies of seed transmission are poorly understood. Host gene expression in response to Epichloë sp. LpTG-3 strain AR37 was examined within inflorescence primordia and ovaries of high and low endophyte transmission genotypes within a single population of perennial ryegrass. A genome-wide association study was conducted to identify population-level single nucleotide polymorphisms (SNPs) and associated genes correlated with vertical transmission efficiency. For low transmitters of AR37, upregulation of perennial ryegrass receptor-like kinases and resistance genes, typically associated with phytopathogen detection, comprised the largest group of differentially expressed genes (DEGs) in both inflorescence primordia and ovaries. DEGs involved in signaling and plant defense responses, such as cell wall modification, secondary metabolism, and reactive oxygen activities were also abundant. Transmission-associated SNPs were associated with genes for which gene ontology analysis identified “response to fungus” as the most significantly enriched term. Moreover, endophyte biomass as measured by quantitative PCR of Epichloë non-ribosomal peptide synthetase genes, was significantly lower in reproductive tissues of low-transmission hosts compared to high-transmission hosts. Endophyte seed-transmission efficiency appears to be influenced primarily by plant defense responses which reduce endophyte colonization of host reproductive tissues.

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Signalling in the Epichloë festucae: Perennial Ryegrass Mutualistic Symbiotic Interaction

Cited by 6 publications

References 175 publications

Redox Regulation of an AP-1-Like Transcription Factor, YapA, in the Fungal Symbiont Epichloë festucae

Redox Regulation of an AP-1-Like Transcription Factor, YapA, in the Fungal Symbiont Epichloë festucae

Deletion of the Fungal Gene soft Disrupts Mutualistic Symbiosis between the Grass Endophyte Epichloë festucae and the Host Plant

Epichloë seed transmission efficiency is influenced by plant defense response mechanisms

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