Entomopathogenic fungi: beyond biocontrol-unravelling mechanisms of enhanced plant abiotic stress tolerance

Rising global food demand requires sustainable strategies to mitigate crop yield losses caused by biotic and abiotic stresses. Entomopathogenic fungi (EPF), traditionally used as biocontrol agents against insect pests, also exhibit a remarkable ability to live within plants as endophytes, significantly boosting plant resilience to abiotic stresses. This review summarises the mechanisms by which EPF endophytes colonise plants and confer robust tolerance to drought, salinity, and heavy metal toxicity. These beneficial fungi orchestrate host physiological adaptations by activating antioxidant systems, up-regulating stress-responsive genes, modulating phytohormone signalling, and enhancing nutrient assimilation. Through improved photosynthetic efficiency, osmotic adjustment, nutrient uptake, and ion homeostasis, EPF endophytes substantially increase plant biomass, yield stability, and productivity under severe stress. Harnessing these fungi as dual-purpose bioagents offers a sustainable alternative to chemical pesticides, bridging ecological pest and disease management and climate-resilient agriculture. Future efforts must prioritise optimising field efficacy and overcoming regulations and commercialisation barriers to unlock their full potential in sustainable global food systems.