Inoculation of Priestia megaterium confers drought tolerance to garden pea (Pisum sativum)

A pot experiment was conducted to evaluate the potential of six PGP microbial isolates (FM20, FM65, FM19, W22, OF5, and Control) to mitigate the adverse effects of drought stress (40% FC) on pea (Pisum sativum) compared to normal irrigation (80% FC). The results demonstrated that PGP inoculants significantly enhanced physiological, ionic, and yield parameters under both normal and stress conditions consistently outperforming the uninoculated control. Under drought stress, W22 maintained the highest Relative Water Content (88.5%), statistically similar to several normal treatments, indicating superior water balance maintenance. In terms of ionic homeostasis, isolate FM20 was the most superior, achieving a 17.23% reduction in the detrimental Na/K ratio in straw compared to the stressed control and the largest reduction in Na-grain content (− 10.53%), confirming its role as the best absolute Na excluder. Under normal irrigation condition FM65 maximized both seed weight per plant (6.7 g) and 100 seed weight (22.9 g). On the other hand under drought (40% FC) OF5 yielded the highest seed weight per plant (7.3 g) and W22 produced the largest 100 seed weight (8.7 g). Collectively, the results confirm that PGP microbial inoculants, particularly FM65, OF5, and W22, offer a viable, strain-specific strategy to stabilize physiological functions, enhance nutrient utilization, and significantly alleviate drought-induced yield reduction in P. sativum.