Phosphorus-Accumulating and Solubilizing Bacteria Improve Soil Attributes and Plant Growth Through Biochemical Changes of Wheat Under Drought and Salinity Stress

Rhizosphere microorganisms, including phosphorus-solubilizing bacteria (PSB) and phosphorus-accumulating bacteria (PAB), are vital for the global phosphorus cycling process. While the role of PSB in enhancing plant phosphorus uptake is known, their combined application with PAB under abiotic stress is not well understood. This experiment aimed to investigate the individual and combined effects of PSB and PAB on soil properties, plant yield, photosynthesis, malondialdehyde (MDA), proline, and fatty acid profile of wheat plants. Different bacterial strains, including Bacillus Amyloliquefaciens FZB42 (PSB1), Bacillus aquimaris S2-5 (PSB2), and Pseudomona putida CA-3 (PAB) were used, both alone and in combination. The plants were also subjected to drought (50% soil field capacity) and salinity (100 mM NaCl). The results showed that drought and salinity deceased soil total porosity, available water content, grain yield, chlorophyll (Chl) a + b, relative water content (RWC), but increased MDA and proline content. The use of PSB and PAB particularly PSB2+PAB significantly improved plant performance through improving biochemical changes in the wheat plants. In drought-exposed plants, PSB2+PAB increased grain yield (23%), RWC (18%), Chl (15%), stearic acid (19%), and oleic acid (31%), but decreased MDA (18%) and linolenic acid (14%). Salinity and drought remarkably led to increased polyunsaturated fatty acids but decreased monounsaturated fatty acids and saturated fatty acids of wheat grains. According to heat map and agglomerative hierarchy clustering, the combined PSB and PAB were grouted in a superior cluster than other bacterial treatments. Combining PSB2 and PAB was found to improve wheat productivity and yield under drought and salinity stress.