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The inoculation of Epichloë endophytes into modern cereals, resulting in systemic infection, depends on the genetics of both the host and the endophyte strain deployed. Until very recently, the only modern cereal to have been infected with Epichloë, in which normal phenotype seed-transmitted associations were achieved, is rye (Secale cereale). Whilst minor in-roads have been achieved in infecting hexaploid wheat (Triticum aestivum), the phenotypes of these associations have all been extremely poor, including host death and stunting. To identify host genetic factors that may impact the compatibility of Epichloë infection in wheat, wheat–alien chromosome addition/substitution lines were inoculated with Epichloë, and the phenotypes of infected plants were assessed. Symbioses were identified whereby infected wheat plants were phenotypically like uninfected controls. These plants completed their full lifecycle, including the vertical transmission of Epichloë into the next generation of grain, and represent the first ever compatible wheat–Epichloë associations to be created. [ABSTRACT FROM AUTHOR]

Elymus dahucirus is an essential plant for ecological restoration in fragile ecological areas and mining area restoration. As lawn grass, it can quickly cover soil and prevent soil erosion, so it is commonly used as a pioneer grass for lawn greening and slope protection. In recent years, with the development of mineral resources, Qinghai–Tibet Plateau soil is facing the threat of heavy metal cadmium (Cd) pollution. E. dahuricus can host the filamentous fungus Epichloë bromicola. To make better use of the advantages that Epichloë bring to host plants to alleviate heavy metal pollution in soil, plant growth and antioxidant capacity effects on E. bromicola infected (E+) and uninfected (E−) E. dahuricus were determined under Cd stress. During Cd treatment, plant growth was decreased by Cd stress, while E+ plants exhibited equal or better growth compared to E− plants. Cd treatment induces a proline and antioxidant enzyme burst in infected plants, while malondialdehyde (MDA) increases. E. bromicola improved plant growth and antioxidant capacity. E. dahuricus breeding strategies could use the information here in efforts to improve the performance of E. dahuricus in both environmental protection and agronomic contexts. [ABSTRACT FROM AUTHOR]

Epichloë spp. often formmutualistic interactions with cool-season grasses, such as Lolium perenne. However, the molecular mechanisms underlying this interaction remain poorly understood. In this study, we employed reduced representation bisulfite sequencing method (epiGBS) to investigate the impact of the Epichloë sp. LpTG-3 strain AR37 on the methylome of L. perenne across multiple grass generations and under drought stress conditions. Our results showed that the presence of the endophyte leads to a decrease in DNAmethylation across genomic features, with differentially methylated regions primarily located in intergenic regions and CHH contexts. The presence of the endophyte was consistently associated with hypomethylation in plants across generations. This research sheds new light on the molecular mechanisms governing the mutualistic interaction between Epichloë sp. LpTG-3 strain AR37 and L. perenne. It underscores the role of methylation changes associated with endophyte infection and suggests that the observed global DNA hypomethylation in L. perennemay be influenced by factors such as the duration of the endophyte-plant association and the accumulation of genetic and epigenetic changes over time. [ABSTRACT FROM AUTHOR]

Epichloë fungal endophytes that systemically colonise cool-season grasses have become an internationally well-researched symbiosis. While sexual species of Epichloë can cause choke disease of grass seed heads, asexual forms are symptomless endophytes that colonise embryos to become seed transmitted. In mutualistic associations, the grass benefits through greater tolerance of abiotic and biotic stresses. In New Zealand, at least 12 species of naturalised and native grasses have been documented as infected with a range of asexual or sexual Epichloë. The impact of endophyte-infected ryegrass and tall fescue has been significant for pastoral farmers, with Epichloë enhancing pasture performance. Production of bioactive secondary metabolites reduces herbivory by invertebrate pests but some are also toxic to grazing animals. Selected strains of Epichloë have been utilised to reduce livestock problems while retaining improved pasture performance. Documented Epichloë-infected native grasses are rare, justifying greater efforts of discovery, description and conservation as taonga (a treasure) for Māori and all New Zealanders. Given their ecological success in New Zealand ecosystems, along with economic and environmental benefits, there are good prospects to further develop both endemic and naturalised Epichloë-grass associations that may benefit other cool-season grasses and potentially deliver new beneficial properties. [ABSTRACT FROM AUTHOR]

Epichloe endophytes (Clavicipitaceae) infect pooid grass genera worldwide but predominantly in the Northern Hemisphere, but appear to be rare in native grasses of the Southern Hemisphere. Because of benefits that hosts may receive from the symbiosis, Epichloe endophytes have been extensively studied and are considered important components of sustainable agriculture. There are only a few studies available on the incidence of endophyte infection in grasses of the Southern Hemisphere and most grass species have never been examined. Here we report on a survey of native grasses of New Zealand including 25 endemic or indigenous species. We sampled up to 10 plants per species at different sites from both the North and South Island of New Zealand and examined tissues microscopically for endophyte infection. Overall, only two species were found to be infected, Poa matthewsii (Matthew's bluegrass) and Dichelachne micrantha (short-hair plume grass). Based on analyses of tefA and tubB genes, both endophytes were found to be interspecific hybrids. The endophyte of the new host D. micrantha was previously described as Epichloe australiensis, while the endophyte of P. matthewsii is a new species named here E. novae-zelandiae. The new species is a hybrid derived from E. amarillans, E. bromicola and E. typhina subsp. poae. Alkaloid analyses in planta suggested that E. novae-zelandiae can produce small amounts of peramine, early pathway indole-diterpenes and ergot alkaloids, but no lolines or lolitrems. Target specific primers suggested the presence of genes for ergot alkaloids and peramine, but genes of only early pathway steps for the other alkaloids. Furthermore, genes for both mating type idiomorphs (MTA and MTB) were present, a single copy of MTA and two copies of MTB. Endophytes of native grasses may provide a genetic resource that could be exploited for developing pasture grass cultivars with improved performance. [ABSTRACT FROM AUTHOR]

Epichloë species are biotrophic symbionts of many cool-season grasses that can cause grazing animal toxicosis. We identified fungi from Hordeum brevisubulatum as Epichloë bromicola based on morphological characteristics and tefA and actG gene sequences. Three isolates were examined, they contained perA gene and 10 out of the 14 EAS cluster genes, previously identified in Epichloë inebrians E818. Five out of 11 LTM/IDT cluster genes previously identified in Epichloë festucae Fl1 were present, but no idtG, indicating an inability to produce even early intermediates in the lolitrem B pathway. Only one lolC gene out of 11 LOL cluster genes previously identified in E. festucae E2368 was present in the three isolates. Chemotype analyses revealed infected samples contained only peramine, and not ergine, ergonovine, ergovaline or lolitrem B. This study provides new information about the host range and phylogenetic definition of E. bromicola and reveal a novel endophyte-grass combination in China. [ABSTRACT FROM AUTHOR]

Secreted proteins, those involved in cell wall biogenesis, are likely to play a role in communication in the symbiotic interaction between the fungal endophyte Epichlo¨e festucae with perennial ryegrass (Lolium perenne), particularly given the close association between fungal hyphae and the plant cell wall. Our hypothesis was that secreted proteins are likely to be responsible for establishing and maintaining a normal symbiotic relationship. We analyzed an endophyte EST database for genes with predicted signal peptide sequences. Here, we report the identification and characterization of rhgA; a gene involved in the regulation of hyphal growth in planta. In planta analysis of ΔrhgA mutants showed that disruption of rhgA resulted in extensive unregulated hyphal growth. This phenotype was fully complemented by insertion of the rhgA gene and suggests that rhgA is important for maintaining normal hyphal growth during symbiosis. [ABSTRACT FROM AUTHOR]

• The relationship between cool-season grasses and fungal endophytes is widely regarded as mutualistic, but there is growing uncertainty about whether changes in resource supply and environment benefit both organisms to a similar extent. • Here, we infected two perennial ryegrass ( Lolium perenne) cultivars (AberDove, Fennema) that differ in carbohydrate content with three strains of Neotyphodium lolii (AR1, AR37, common strain) that differ intrinsically in alkaloid profile. We grew endophyte-free and infected plants under high and low nitrogen (N) supply and used quantitative PCR (qPCR) to estimate endophyte concentrations in harvested leaf tissues. • Endophyte concentration was reduced by 40% under high N supply, and by 50% in the higher sugar cultivar. These two effects were additive (together resulting in 75% reduction). Alkaloid production was also reduced under both increased N supply and high sugar cultivar, and for three of the four alkaloids quantified, concentrations were linearly related to endophyte concentration. • 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 N inputs affect the role of endophytes in grassland ecosystems. [ABSTRACT FROM AUTHOR]

Epichloë spp. often form mutualistic interactions with cool-season grasses, such as Lolium perenne . However, the molecular mechanisms underlying this interaction remain poorly understood. In this study, we employed reduced representation bisulfite sequencing method (epiGBS) to investigate the impact of the Epichloë sp. Lp TG-3 strain AR37 on the methylome of L. perenne across multiple grass generations and under drought stress conditions. Our results showed that the presence of the endophyte leads to a decrease in DNA methylation across genomic features, with differentially methylated regions primarily located in intergenic regions and CHH contexts. The presence of the endophyte was consistently associated with hypomethylation in plants across generations. This research sheds new light on the molecular mechanisms governing the mutualistic interaction between Epichloë sp. Lp TG-3 strain AR37 and L. perenne . It underscores the role of methylation changes associated with endophyte infection and suggests that the observed global DNA hypomethylation in L. perenne may be influenced by factors such as the duration of the endophyte-plant association and the accumulation of genetic and epigenetic changes over time., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Forte, Malinowska, Nagy, Schmid, Dijkwel, Hume, Johnson, Simpson and Asp.)