Screening and evaluation of PGPR strains having multiple PGP traits from hilly terrain

ABSTRACT

Plant growth-promoting rhizobacteria (PGPR) with multiple beneficial traits serve as potentially, ecofriendly,and cost-effective alternatives to chemical fertilizers and pesticides. They have both direct and indirectaffirmative impacts on overall plant growth and health. PGPRs are well known to directly improve the plantgrowth by phytohormone production and availability of minerals in soil. A total of nine soil samples were takenfrom near the rhizospheric zone of different crops and 56 rhizobacterial strains were isolated. Only 16 out of56 rhizobacterial strains were found positive for more than one beneficial trait that included solubilization ofphosphate, indole acetic acid (IAA), siderophore, ammonia and H2S production. Among all PGPR strains,RKM15 was observed having the highest phosphate solubilizing index (3.4), solubilized phosphorus (339mg L−1) and also siderophore unit (70.54 %). The maximum IAA production was observed by RKM25 strain(35.56 µg ml−1). The most promising RKM15 isolate was identified as Pantoea dispersa (MN629239) through16S rRNA gene sequencing technique. This characterized PGPR strain may be used for the development ofbiofertilizers to enhance crop productivity and improvement in soil fertility