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

Abstract

Soil salinity remains a major abiotic factor limiting agricultural productivity worldwide, with the situation worsening in parts of Maharashtra, particularly Karad Taluka. This study examined saline soils from various locations within Karad, assessing their physicochemical properties and isolating indigenous halotolerant bacterial strains that exhibit plant growthpromoting rhizobacterial (PGPR) traits. The soil analysis revealed highly alkaline pH levels (8.8-9.4), elevated sodium concentrations, and deficiencies in organic carbon, nitrogen, and micronutrients. Five halotolerant bacterial isolates (Ko1, Va1, Be1, Vm1, and At1) were obtained and evaluated for PGPR activities such as phosphate and potassium solubilization, nitrogen fixation, indole-3-acetic acid (IAA) production, and siderophore synthesis. All isolates demonstrated positive results in phosphate and potassium solubilization, nitrogen fixation, and IAA production, with four also producing siderophores. Notably, isolates Be1, Vm1, and At1 showed strong performance across multiple traits, highlighting their potential as bioinoculant candidates. These findings suggest that native halotolerant PGPR strains from Karad Taluka could enhance soil fertility, improve nutrient uptake, and support plant growth in saline conditions. Future research including field trials and molecular characterization could facilitate the development of environmentally sustainable microbial formulations for saline agriculture.