Recent Advances in PGPR and Molecular Mechanisms Involved in Drought Stress Resistance

Increased severity of droughts, due to anthropogenic activities and global warming, has imposed a severe threat on agricultural productivity. This has escalated the need for environmentally sustainable solutions to secure global food security. In this context, the application of plant growth-promoting rhizobacteria (PGPR) can be beneficial. PGPR through various mechanisms viz. osmotic adjustments, increased antioxidant activity, phytohormone production, etc., not only ensure the plant's survival during drought but also augment its growth. Further, due to recent advances in omics technologies, better insights are emerging for PGPR, which facilitates the exploration of genes that are responsible for plant tissue colonization. This review extensively discusses the various mechanisms of PGPR in drought stress resistance; we have also summarized the recent molecular and omics-based approaches for elucidating the role of drought-responsive genes. The manuscript comprises the in-depth mechanistic approach along with designing the PGPR-based bioinoculants to combat drought stress and a possible flowchart for increasing their efficacy.