Plant growth-promoting and protective potential of root fungal endophytes associated with a pioneer grass, Saccharum spontaneum L., from a lahar-affected area

Root-associated mycobiota can improve nutrient assimilation and induce resistance in their host plants. In this study, we isolated root fungal endophytes (RFE) from Saccharum spontaneum, a pioneer grass thriving in a lahar-strewn environment. Seventeen root fungal endophytes identified as belonging to the genera Talaromyces, Penicillium, Fusarium, Trichoderma, Cladosporium, Epicoccum, Purpureocillium, and Rhizoctonia were screened for plant growth-promoting and protective properties. The colorimetric assay revealed significantly high levels of the phytohormone indole-3-acetic acid (20.13–159.89 µg/ml), which was produced by eight notable RFE isolates. Seven of the root fungal endophytes displayed phosphate solubilizing activities with a solubilization index (SI) ranging from 1.04–1.22 on Pikovskaya’s agar. Nine RFE isolates significantly suppressed the growth of the phytopathogen, Fusarium oxysporum, exhibiting > 50% inhibition rates in a dual culture experiment. Our study highlighted the beneficial traits of root fungal endophytes, which might be responsible for the successful colonization of lahar areas by the pioneer grass S. spontaneum.