Effect of Epichloë Endophytes on Growth of Grass Pathogenic Fungi

Endophytic fungi widely colonize plant tissues without causing severe disease, protect hosts from pathogenic microorganisms, and represent a key potential resource for novel biocontrol agents. To explore the biocontrol potential of endophytic <i>Epichloë</i> fungi and their correlation with alkaloids, 12 <i>Epichloë</i> strains were isolated from six different geographic sites of <i>Festuca sinensis</i>, <i>Achnatherum inebrians</i>, and <i>Hordeum brevisubulatum</i>. The antifungal activity of these strains was evaluated against five phytopathogenic fungi (<i>Alternaria alternata</i>, <i>Bipolaris sorokiniana</i>, <i>Curvularia lunata</i>, <i>Fusarium avenaceum</i>, and <i>Drechslera erythrospila</i>) using dual-culture assays, which measured the inhibition of both colony growth and spore germination. Concurrently, the concentrations of ergonovine and ergine were quantified in the liquid cultures of each <i>Epichloë</i> strain. The results showed that 12 <i>Epichloë</i> strains had varying degrees of inhibitory effects on the colony growth and spore germination of five pathogenic fungi. Among these, strain F2 had the highest inhibition rate on the spore germination of <i>B. sorokiniana</i> (87.73%), while strain H3 had the lowest inhibition rate on <i>F. avenaceum</i> (7.89%). The concentrations of ergonovine and ergine were positively correlated with the inhibition rate of pathogenic fungi, but the degree of these correlations varied among different pathogenic fungi. This study provides further evidence for <i>Epichloë</i>-mediated pathogen inhibition and establishes a basis for their development as biocontrol agents in agricultural systems.