Microbial Interventions for Sustainable Agriculture: PGPR Activity of Isolates of Saline Soils from Karad Taluka (Maharashtra, India)

Abstract

Soil salinity is a key abiotic factor that limits agricultural output worldwide, and the problem is getting worse in parts of Maharashtra, especially Karad Taluka. The current work examined saline soils from various places in Karad, evaluating their physicochemical features and isolating indigenous halotolerant bacterial strains with plant growth-promoting rhizobacteria (PGPR) attributes. Soil study revealed a strongly alkaline pH (8.8-9.4), high sodium levels, and shortages in organic carbon, nitrogen, and micronutrients. Five halotolerant bacterial isolates (Ko1, Va1, Be1, Vm1, and At1) were isolated and tested for PGPR activities including phosphate and potassium solubilisation, nitrogen fixation, indole-3-acetic acid (IAA) generation, and siderophore synthesis. All isolates shown positive activity in phosphate and potassium solubilisation, nitrogen fixation, and IAA generation, with four additionally producing siderophores. Isolates Be1, Vm1, and At1 performed well across multiple traits, making them interesting candidates for bioinoculant development. The findings indicate that native halotolerant PGPR from Karad Taluka can help improve soil fertility, increase nutrient uptake, and promote plant development in salt-affected areas. Future field validation and molecular characterisation could help build environmentally friendly microbial formulations for saline agriculture.