Physio-Biochemical Insights of Endophytic Microbial Community for Crop Stress Resilience: An Updated Overview

Due to the ongoing improvement in living standards, the demand for chemical-free organic food is continuously rising. Against this background, the use of non-chemical sources of plant growth-promoting agents, as well as biotic/abiotic stress-alleviating factors, is in demand. On this basis, plant endophytes are currently attracting worldwide interest, owing to their wide range of applications opening opportunities for the agricultural sector. Endophytes inhabit symbiotically within the plant endosphere, and reside asymptomatically inside the cellular environment without harming their host. These endophytes possess a wide variety of applications in diverse fields, including agricultural, medical, and nutraceutical ones. Concerning plant system, they improve the physiology, fitness, and metabolomic profile of the plants through the synthesis of phytohormones, secondary metabolites, antibiotics, siderophores as well as fertilizers. They can also be employed for phytoremediation of pollutants. They may be considered a promising avenue for pest management, as they are eco-friendly and sustainable. Owing to their beneficial properties on plant and soil systems without harming the ecosystem, they are attracting the widespread interest of the agricultural industry, and academia. Although a large body of research has been formerly conducted on exploring the different applications of endophytes, investigations still needs to be undertaken prior to their commercialization. In this paper, we reviewed the major bacterial and fungal endophytes that originated from plant species and their key functions in pest and disease management along with plant growth promotion attributes. The major compounds identified in these endophytes and their role in pest and disease management are further discussed to decipher the mode of action.