Recent advances of plant growth-promoting rhizobacteria (PGPR)-mediated drought and waterlogging stress tolerance in plants for sustainable agriculture

Abiotic stressors, such as drought and waterlogging, rank among the most critical environmental factors that significantly limit agricultural production on a global scale. Drought stress induces water losses and stomatal closure, decreases cell turgor pressure and water potential, restricts cell growth, hampering crop yield, while waterlogging stress diminishes soil oxygen, limits metabolism of energy, and hampers growth and developmental processes of plant. Plants react to waterlogging stress through regulating morphological characteristics, metabolism of energy, signaling processes, reactive oxygen species generation, and endogenous hormone biosynthesis. However, several solutions tried to overcome this hurdle are not justifiable and are solitary effective for the little period. Plant growth-promoting rhizobacteria (PGPR) can generate various plant-derived compounds, for instance indole acetic acid and gibberellins. Under drought and waterlogging conditions, PGPR also produced numerous active enzymes. This methodology enhances growth of plant and therefore increases crop harvest with sustained eco-friendly environment. This chapter addresses the current developments of PGPR approach in context to drought and waterlogging stresses. In this comprehensive review, we systematically summarize the biochemical, physiological, metabolic, and molecular responses of plants to both waterlogging and drought stress, as well as effective management strategies for promoting sustainable agriculture. Further, we discuss drought and waterlogging stress tolerance induced by plant growth-promoting bacteria. Finally, we explore biotechnological strategies such as genetic engineering and genome editing approaches that have used this molecular knowledge to develop plant varieties that tolerate drought and waterlogging stress.