Isolation of endophytic bacteria from green gram and study on their plant growth promoting activities

Abstract

ABSTRACT: A total of twenty five endophytic bacteria were isolated from green gram Vigna radiata (L.) plant. Four isolates which have shown better response for plant growth promoting effects on green gram plants were used as Plant Growth Promoting Bacteria (PGPB) in this study. It has been detected that up to 40% of the genomic 16S rRNA of isolated bacteria belongs to the Azotobacter genus. The result for phosphate solubilizing activities in NPRIB broth and Pikovskaya broth by UV-VIS Spectrophotometer (830 nm) showed that isolate FR was the best candidate in solubilizing of phosphorous showing 49.817Ppm with NPRIB broth and 53.534Ppm with Pikovskaya broth,respectively. Of all studied endophytes, isolates NL and NR have shown high nitrogenase activities and the activities being 2570.40 and 2108.00 n mole of C2H4 ml-1h-1 respectively. These strains will be selected for further use. The IAA production of all isolates was identified by FTIR spectroscopy and Spectrum for Crude IAA Extract of isolate FL is the best candidate for IAA production. The insoluble Potassium (K+) content in mica sample and the soluble K+ content by the inoculated samples were analyzed the atomic absorption spectrophotometric (AAS) method and isolates FL, FR, and NR were found to be good at decomposing insoluble potassium. These results indicated that the selected all four endophytic microbes could be excellent candidates for use as biofertilizer.