Functional dynamics of Plant Growth-Promoting Bacteria (PGPB) in Adaptation to Abiotic Stress and Enhancement of Crop Productivity.

<p>In the context of sustainable agriculture, plant growth-promoting bacteria (PGPB) are key microbial biostimulants. These beneficial microorganisms enhance nutrient uptake, strengthen plant defence mechanisms, and improve tolerance to abiotic stresses, contributing to reduced reliance on chemical inputs. Bacterial genera such as <em>Azospirillum</em>, <em>Rhizobium</em>, <em>Bacillus</em>, and <em>Pseudomonas</em> have demonstrated positive effects on crop yield and quality, even under challenging conditions including salinity, drought, and heavy metal contamination. Their beneficial actions include several mechanisms, such as phytohormone production, nutrient solubilization, nitrogen fixation, and modulation of gene expression linked to plant defence and metabolism. The efficacy of these bacteria varies according to microbial strain, plant species, and environmental context. This review shows the agronomic value of PGPB and emphasizes the importance of continued research into their functional interactions in resilient and environment-friendly farming systems.</p>