A Metabolomic Study of Epichloë Endophytes for Screening Antifungal Metabolites

• Published in: Metabolites Vol. 12; no. 1; p. 37
• Main Authors: Fernando, Krishni, Reddy, Priyanka, Guthridge, Kathryn M, Spangenberg, German C, Rochfort, Simone J
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04-01-2022; MDPI
• Subjects: Agricultural production; Animal welfare; Antifungal activity; antifungals; Bioactive compounds; bioassay-guided extraction; Bioassays; Biological activity; Chromatography; Disease control; Disease resistance; Endophytes; Endosymbionts; Epichloë derived bioprotectives; Fractionation; Grasses; Investigations; known unknowns; Mammals; Metabolites; Metabolomics; Pasture; pasture and turf protection; Pathogens; Phytopathogenic fungi; Plant diseases; Scientific imaging; Turf; untargeted analysis; Epichloë derived bioprotectives; known unknowns; untargeted analysis; bioassay; pasture and turf protection; antifungals; bioassay-guided extraction
• ISSN: 2218-1989; 2218-1989
• DOI: 10.3390/metabo12010037

endophytes, fungal endosymbionts of Pooidae grasses, are commonly utilized in forage and turf industries because they produce beneficial metabolites that enhance resistance against environmental stressors such as insect feeding and disease caused by phytopathogen infection. In pastoral agriculture, phytopathogenic diseases impact both pasture quality and animal production. Recently, bioactive endophyte strains have been reported to secrete compounds that significantly inhibit the growth of phytopathogenic fungi in vitro. A screen of previously described
-produced antifeedant and toxic alkaloids determined that the antifungal bioactivity observed is not due to the production of these known metabolites, and so there is a need for methods to identify new bioactive metabolites. The process described here is applicable more generally for the identification of antifungals in new endophytes. This study aims to characterize the fungicidal potential of novel, 'animal friendly'
endophyte strains NEA12 and NEA23 that exhibit strong antifungal activity using an in vitro assay. Bioassay-guided fractionation, followed by metabolite analysis, identified 61 metabolites that, either singly or in combination, are responsible for the observed bioactivity. Analysis of the perennial ryegrass-endophyte symbiota confirmed that NEA12 and NEA23 produce the prospective antifungal metabolites in symbiotic association and thus are candidates for compounds that promote disease resistance
. The "known unknown" suite of antifungal metabolites identified in this study are potential biomarkers for the selection of strains that enhance pasture and turf production through better disease control.