Endophyte-induced physiological adjustments to improve drought tolerance in rice

Fungal endophytes are known to improve plant resilience by influencing a wide range of physiological, biochemical, and molecular processes. The endophytes adapted to stress-prone habitats have emerged as promising biological agents for enhancing crop tolerance under water-limited conditions. In the present study, two fungal endophytes, Fusarium incarnatum (K23) and Fusarium equiseti (SF5), isolated from contrasting extreme environments, mitigated the adverse effects of drought across three rice varieties, namely, IR64, CR Dhan 307, and Sahbhagi Dhan. Endophyte colonization significantly increased root and shoot biomass under drought, with SF5 outperforming K23 in most parameters. Colonization of endophytes improved physiological and biochemical parameters under drought in all three rice varieties. Additionally, both endophytes contributed to oxidative stress management under drought. Agronomic traits, including plant height, panicle weight, and grain weight, were also significantly improved under drought conditions with endophyte colonization. SF5 showed specificity in enhancing reproductive traits in Sahbhagi Dhan, whereas K23 demonstrated broader efficacy across all varieties. Correlation analysis highlighted the interplay between antioxidant enzyme activities and yield components. Current findings suggest that habitat-adapted endophytic fungi, offer an effective, variety-specific strategy to improve drought tolerance and crop productivity in rice. This research provides insights into beneficial endophytic inoculants for sustainable agriculture in water-limited environments.