Different response of perennial ryegrass-Epichloe endophyte symbiota to the elevated concentration of heavy metals in soil.
Ontology highlight
ABSTRACT:
SUBMITTER: Zurek G
PROVIDER: S-EPMC8755660 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Perennial ryegrass (Lolium perenne L.) is one of the most important species for temperate pastoral agriculture, forming associations with genetically diverse groups of mutualistic fungal endophytes. However, only two taxonomic groups (E. festucae var. lolii and LpTG-2) have so far been described. In addition to these two well-characterised taxa, a third distinct group of previously unclassified perennial ryegrass-associated endophytes was identified as belonging to a putative novel taxon (or taxa) (PNT) in a previous analysis based on simple sequence repeat (SSR) marker diversity. As well as genotypic differences, distinctive alkaloid production profiles were observed for members of the PNT group.A detailed phylogenetic analysis of perennial ryegrass-associated endophytes using components of whole genome sequence data was performed using complete sequences of 7 nuclear protein-encoding genes. Three independently selected genes (encoding a DEAD/DEAH box helicase [Sbp4], a glycosyl hydrolase [family 92 protein] and a MEAB protein), none of which have been previously used for taxonomic studies of endophytes, were selected together with the frequently used 'house-keeping' genes tefA and tubB (encoding translation elongation factor 1-? and ?-tubulin, respectively). In addition, an endophyte-specific gene (perA for peramine biosynthesis) and the fungal-specific MT genes for mating-type control were included. The results supported previous phylogenomic inferences for the known species, but revealed distinctive patterns of diversity for the previously unclassified endophyte strains, which were further proposed to belong to not one but two distinct novel taxa. Potential progenitor genomes for the asexual endophytes among contemporary teleomorphic (sexual Epichloë) species were also identified from the phylogenetic analysis.Unique taxonomic status for the PNT was confirmed through comparison of multiple nuclear gene sequences, and also supported by evidence from chemotypic diversity. Analysis of MT gene idiomorphs further supported a predicted independent origin of two distinct perennial ryegrass-associated novel taxa, designated LpTG-3 and LpTG-4, from different members of a similar founder population related to contemporary E. festucae. The analysis also provided higher resolution to the known progenitor contributions of previously characterised perennial ryegrass-associated endophyte taxa.
| S-EPMC4458015 | biostudies-literature
Project description:The cuticular wax serves as the outermost hydrophobic barrier of plants against nonstomatal water loss and various environmental stresses. An objective of this study was to investigate the contribution of the mutualistic fungal endophyte Epichloë gansuensis to leaf cuticular wax of Achnatherum inebrians under different soil moisture availability. Through a pot experiment and gas chromatography−mass spectrometry (GC−MS) analysis, our results indicated that the hydrocarbons were the dominant components of leaf cuticular wax, and the proportion of alcohols, aldehydes, amines, and ethers varied with the presence or absence of E. gansuensis and different soil moisture availability. Amines and ethers are unique in endophyte-free (EF) A. inebrians plants and endophyte-infected (EI) A. inebrians plants, respectively. By transcriptome analysis, we found a total of 13 differentially expressed genes (DEGs) related to cuticular biosynthesis, including FabG, desB, SSI2, fadD, BiP, KCS, KAR, FAR, and ABCB1. A model is proposed which provides insights for understanding cuticular wax biosynthesis in the association of A. inebrians plants with E. gansuensis. These results may help guide the functional analyses of candidate genes important for improving the protective layer of cuticular wax of endophyte-symbiotic plants.
| S-EPMC9325231 | biostudies-literature
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
Project description:Seed-borne fungal symbionts (endophytes) provide many cool-season grass species with biological protection from biotic and abiotic stresses. The endophytes are asexual, whereas closely related sexual species of genus Epichloë (Clavicipitales) cause grass choke disease. Perennial ryegrass (Lolium perenne) is a host of two endophyte taxa, LpTG-1 (L. perenne endophyte taxonomic grouping one = Acremonium lolii) and LpTG-2, as well as the choke pathogen, Epichloë typhina (represented by isolate E8). Relationships among these fungi and other Epichloë species were investigated by analysis of gene sequences, DNA polymorphisms and allozymes. The results indicate that LpTG-2 is a heteroploid derived from an interspecific hybrid. The LpTG-2 isolates had two copies each of nine out of ten genes analyzed (the exception being the rRNA gene locus), and the profiles for seven of these were composites of those from E. typhina E8 and A. lolii isolate Lp5. Molecular phylogenetic analysis grouped the two beta-tubulin genes of LpTG-2 into separate clades. One (tub2-1) was related to that of E. typhina E8, and the other (tub2-2) to that of A. lolii. The mitochondrial DNA profile of LpTG-2 was similar to that of A. lolii, but its rRNA gene sequence grouped it with E. typhina E8. A proposed model for the evolution of LpTG-2 involves infection of a L. perenne-A. lolii symbiotum by E. typhina, followed by hybridization of the two fungi. Such interspecific hybridization may be a common and important mechanism for genetic variation in Epichloë endophytes.
| S-EPMC1205911 | biostudies-other
Project description:Perennial ryegrass (Lolium perenne) is the most cultivated cool-season grass worldwide with crucial roles in carbon fixation, turfgrass applications, and fodder for livestock. Lolium perenne forms a mutualism with the strictly vertically transmitted fungal endophyte, Epichloë festucae var lolii. The fungus produces alkaloids that protect the grass from herbivory, as well as conferring protection from drought and nutrient stress. The rising concentration of atmospheric CO2, a proximate cause of climatic change, is known to have many direct and indirect effects on plant growth. There is keen interest in how the nature of this plant-fungal interaction will change with climate change. Lolium perenne is an obligately outcrossing species, meaning that the genetic profile of the host is constantly being reshuffled. Meanwhile, the fungus is asexual implying both a relatively constant genetic profile and the potential for incompatible grass-fungus pairings. In this study, we used a single cultivar, "Alto", of L. perenne. Each plant was infected with one of four strains of the endophyte: AR1, AR37, NEA2, and Lp19 (the "common strain"). We outcrossed the Alto mothers with pollen from a number of individuals from different ryegrass cultivars to create more genetic diversity in the hosts. We collected seed such that we had replicate maternal half-sib families. Seed from each family was randomly allocated into the two levels of the CO2 treatment, 400 and 800 ppm. Elevated CO2 resulted in an c. 18% increase in plant biomass. AR37 produced higher fungal concentrations than other strains; NEA2 produced the lowest fungal concentrations. We did not find evidence of genetic incompatibility between the host plants and the fungal strains. We conducted untargeted metabolomics and quantitative proteomics to investigate the grass-fungus interactions between and within family and treatment groups. We identified a number of changes in both the proteome and metabalome. Taken together, our data set provides new understanding into the intricacy of the interaction between endophyte and host from multiple molecular levels and suggests opportunity to promote plant robustness and survivability in rising CO2 environmental conditions through application of bioprotective epichloid strains.
| S-EPMC7770580 | biostudies-literature
Project description:VelA (or VeA) is a key global regulator in fungal secondary metabolism and development which we previously showed is required during the symbiotic interaction of Epichloë festucae with perennial ryegrass. In this study, comparative transcriptomic analyses of ∆velA mutant compared to wild-type E. festucae, under three different conditions (in culture, infected seedlings, and infected mature plants), were performed to investigate the impact of VelA on E. festucae transcriptome. These comparative transcriptomic studies showed that VelA regulates the expression of genes encoding proteins involved in membrane transport, fungal cell wall biosynthesis, host cell wall degradation, and secondary metabolism, along with a number of small secreted proteins and a large number of proteins with no predictable functions. In addition, these results were compared with previous transcriptomic experiments that studied the impact of LaeA, another key global regulator of secondary metabolism and development that we have shown is important for E. festucae-perennial ryegrass interaction. The results showed that although VelA and LaeA regulate a subset of E. festucae genes in a similar manner, they also regulated many other genes independently of each other suggesting specialised roles.
| S-EPMC7023048 | biostudies-literature
Project description:The rapid identification and quantitation of alkaloids produced by Epichloë endophyte-infected pasture grass is important for the agricultural industry. Beneficial alkaloids, such as peramine, provide the grass with enhanced insect protection. Conversely, ergovaline and lolitrem B can negatively impact livestock. Currently, a single validated method to measure these combined alkaloids in planta does not exist. Here, a simple two-step extraction method was developed for Epichloë-infected perennial ryegrass (Lolium perenne L.). Peramine, ergovaline and lolitrem B were quantified using liquid chromatography-mass spectrometry (LC-MS). Alkaloid linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, precision, selectivity, recovery, matrix effect and robustness were all established. The validated method was applied to eight different ryegrass-endophyte symbiota. Robustness was established by comparing quantitation results across two additional instruments; a triple quadruple mass spectrometer (QQQ MS) and by fluorescence detection (FLD). Quantitation results were similar across all three instruments, indicating good reproducibility. LOQ values ranged from 0.8 ng/mL to 6 ng/mL, approximately one hundred times lower than those established by previous work using FLD (for ergovaline and lolitrem B), and LC-MS (for peramine). This work provides the first highly sensitive quantitative LC-MS method for the accurate and reproducible quantitation of important endophyte-derived alkaloids.
| S-EPMC6891275 | biostudies-literature
Project description:This study was conducted to explore effects of the systemic fungal endophyte Epichloë gansuensis on root and rhizosphere soil bacterial diversity of Achnatherum inebrians host plants growing under different moisture conditions. Soil properties of different treatments were compared using standard techniques. A total of 4371379 16S rRNA gene sequences were obtained and assigned to 5025 operational taxonomic units (OTUs). These OTUs in roots and rhizosphere soil were divided into 13 and 17 phyla, respectively, and the Actinobacteria and Proteobacteria were the most abundant phyla both in roots and rhizosphere soil. Shannon diversity and Chao1 richness index of bacteria in rhizosphere soil was significantly higher than in roots. E. gansuensis decreased the Shannon diversity of the root-associated bacterial community, and increased Shannon diversity and Chao1 richness index of the rhizosphere soil bacterial community of A. inebrians. Meanwhile, Chao1 richness of the rhizosphere soil bacterial community of A. inebrians significantly increased with the increase of the soil moisture level. Structural equation modeling also emphasized that E. gansuensis decreased the diversity of the root-associated bacterial community and increased the diversity of the rhizosphere soil bacterial community through decreasing soil available N. Additionally, soil moisture increased the diversity of the rhizosphere soil bacterial community through increased soil pH, C/N, and NN, and decreased soil AP. The E. gansuensis endophyte and soil moisture effects on root and rhizosphere soil bacterial diversity were likely to be from responses to modifications of the rhizosphere soil properties.
| S-EPMC7181407 | biostudies-literature
Project description:The most potent of the indole diterpenes, lolitrem B, is found in perennial ryegrass (Lolium perenne L.) infected with the endophyte Epichloë festucae var. lolii (also termed LpTG-1). Ingestion causes a neurological syndrome in grazing livestock called ryegrass staggers disease. To enable the rapid development of new forage varieties, the toxicity of lolitrem B and its biosynthetic intermediates needs to be established. However, most of these indole diterpenes are not commercially available; thus, isolation of these compounds is paramount. A concentrated endophyte-infected perennial ryegrass seed extract was subjected to silica flash chromatography followed by preparative HPLC and purification by crystallization resulting in lolitrem B and the intermediate compounds lolitrem E, paspaline and terpendole B. The four-step isolation and purification method resulted in a 25% yield of lolitrem B. After isolation, lolitrem B readily degraded to its biosynthetic intermediate, lolitriol. We also found that lolitrem B can readily degrade depending on the solvent and storage conditions. The facile method which takes into consideration the associated instability of lolitrem B, led to the purification of indole diterpenes in quantities sufficient for use as analytical standards for identification in pastures, and/or for toxicity testing in pasture development programs.
| S-EPMC6356652 | biostudies-literature
Project description:The association between perennial ryegrass (Loliumperenne L.) and its Epichloë fungal endophyte symbiont, Epichloëfestucae var. lolii, supports the persistence of ryegrass-based pastures principally by producing bioactive alkaloid compounds that deter invertebrate herbivory. The host plant genotype affects endophyte trait expression, and elucidation of the underlying genetic mechanisms would enhance understanding of the symbiosis and support improvement of inplanta endophyte performance through plant breeding. Rapid metabolite profiling and enzyme-linked immunosorbent assay were used to quantify endophyte alkaloids and mycelial mass (MM) in leaves harvested, in consecutive autumns, from an F1 mapping population hosting standard toxic endophyte. Co-aligned quantitative trait loci (QTL) on linkage groups (LG)2, LG4 and LG7 for MM and concentrations of alkaloids peramine and ergovaline confirmed host plant effects on both MM and alkaloid level and inferred the effect on alkaloids was modulated through the quantity of endophyte present in the leaf tissue. For ergovaline, host regulation independent of endophyte concentration was also indicated, by the presence of MM-independent ergovaline QTL on LG4 and LG7. Partitioning of host genetic influence between MM-dependent and MM-independent mechanisms was also observed for the alkaloid N-formylloline (NFL), in a second mapping population harbouring a tall fescue-sourced endophyte. Single-marker analysis on repeated MM and NFL measures identified marker-trait associations at nine genome locations, four affecting both NFL and MM but five influencing NFL concentration alone. Co-occurrence of QTL on LG3, LG4 and LG7 in both mapping populations is evidence for host regulatory loci effective across genetic backgrounds and independent of endophyte variant. Variation at these loci may be exploited using marker-assisted breeding to improve endophyte trait expression in different host population × endophyte combinations.
| S-EPMC4506467 | biostudies-literature