Molecular characterization of potential salt tolerant bacteria for soybean growth promotion

Salinity is a major limiting factor for soybean crop productivity. To enhance the tolerance of soybean against salt stress, it is essential to understand the diversity of microbiota harboured by soybean rhizosphere. Earlier studies have demonstrated that local adaptation of plants to habitat imposed stresses is driven by their closely associated microbes. The present study aimed to isolation and characterization of salt tolerant rhizobacteria with respect to their functional plant growth promotion ability. A total of 43 bacterial isolates were recovered from soybean rhizospheric soil grown in Bundi district, Rajasthan, India. Out of them, one bacterial isolate strain AU was found to tolerate 10% NaCl stress and significantly enhanced soybean seedlings growth under 100mM NaCl condition. Molecular phylogenetic analysis placed this isolate closely to Pseudomonas simiae OLi T with 99.93% similarity. Molecular characterization of functional genes revealed that AU bacterium possessed genes like IaaM (IAA production), g6pd (Pi-solubilization) and sid (siderophore production). Here, we show that soybean rhizosphere possessed a salt tolerant plant growth promoting bacterium strain AU, which may have impacts on alleviation and tolerance of salt stress in legume plants.