The role of endophytes to combat abiotic stress in plants

Climatic changes and global warming produce abiotic stressors that affect plant development and productivity. Abiotic stressors, such as drought, salt, cold, and heat, significantly impair global agricultural crop yields. The endophyte is a type of endosymbiont, usually a bacteria or fungus that lives inside plant cells and doesn't cause disease in the host plant. This review scrutinizes the integral contribution of endophytes to augmenting abiotic stress tolerance in plants. The core analysis investigates the regulatory role and mechanism of endophytes in pivotal physiological aspects of plants under abiotic stress conditions. This includes their involvement in managing water uptake and maintaining water balance during drought and salinity stress, regulating osmotic stress, and scavenging reactive oxygen species (ROS). Additionally, the review explores and outlines diverse strategies for inoculating and applying endophytes to enhance abiotic stress tolerance in plants. Endophytes produce secondary active compounds that defend plants from diseases and extracellular enzymes that help endophytes colonize plant hosts. Microbial endophytes may help plants thrive in poor soil conditions through phytohormone production and hazardous chemical degradation. Endophytes use many processes to help plants survive drought, salt, nutritional deficiency, heavy metal stress, and temperature. These findings suggest that endophytes and rhizobacteria may help plants cope with abiotic stress. Still, more research is needed to understand the mechanisms and side effects that maximize their use in sustainable and climate-smart agriculture.