Complementation of Biochemical and Physiological Assays with Functional PGPR Based Assays to Screen Potential Isolates

The work deals with the biochemical characterization of rhizospheric isolates including Indole, Methyl Red, Voges Proskauer, Citrate test (IMViC test) based quantitative biochemical assay, PGPR properties like nitrogen assimilation (in microbes), phosphate solubilization etc. A special aspect of finding the correlation between the biochemical tests and PGPR properties were also studied. Methyl red test and tryptophanase assay (by indole test) were found to be positively and negatively correlated with phosphate solubilization. Vogues Proskeur and citrate utilization tests were negatively correlated with the phosphate solubilization. In future, these biochemical tests can be used as determining factors to identify phosphate solubilizing bacteria. Moreover, a group of bacteria was identified by the scatter plot analysis which shows low acid production with high phosphate solubilization. Lastly, we have given a new approach of screening rhizospheric bacteria based on motility on nitrogen deficient media.