Isolation Characterization and Evaluation of Growth Potential of Plant Growth Promoting Rhizobacteria from Agricultural Fields in Agra

Abstract

Plant growth promoting rhizobacteria (PGPR) are a group of free-living bacteria that possess many traits which make them well suited as biofertilizer agents. In the present study, total 210 soil samples were collected from bare field and rhizosphere of different crops and wild plants from Agra (U.P.) and other sites. A total of 1067 bacteria were isolated and screened for plant growth promoting traits namely, phosphate, potassium and zinc solubilization, and production of siderophores, IAA and ammonia. newlineIsolates having multiple PGP traits were selected for qualitative and quantitative estimation of their PGP traits. Twenty isolates exhibited best PGP traits with higher efficiency. These were characterized, morphologically, biochemically and molecularly using 16S rRNA gene sequencing technique. The BLAST analysis of their 16S rRNA gene sequences showed similarity with certain reported bacteria. All these isolates belonged to two bacterial classes, and#946; proteobacteria and and#947; proteobacteria. newlineThree PGPR isolates were selected for optimization of physical and nutritional parameters. PGPR isolates Advenella kashmirensis ZRA14, B. metallica TARA92 and B. gladioli PRRS35 showed optimal growth at pH 7, 37°C and glucose as the carbon source but all the three had different nitrogen salt requirements and tolerance to sodium chloride. The best PGPR isolate TARA92 was selected for studying its growth kinetics parameters. newlineOf the 20 identified isolates, seven PGPR isolates were selected for evaluation of their efficacy on plant growth promoting activity on Vigna radiata cv. Pusa vishal (mung bean) in pot and field experiment. Application of the PGPR isolates to mung bean increased plant growth, biochemical and yield parameters in comparison to untreated seeds. The maximum enhancement in all these parameters was obtained by treatment with B. metallica TARA92 isolate followed by B. arboris CSRS12, Enterobacter hormaechei, PGRA14, Advenella kashmirensis ZRA14 and E. cloacae BCRA23 over control. These PGPR isolates could be utilized for biofertilizer formulations after some field trials on different economically important crops under agro-climatic conditions in Agra region. newline newline