Combinatorial assessment on dominance and informative diversity of PGPR from rhizosphere of Jatropha curcas L.

The extensive and enduring challenges in soil microbiology depend on the development of efficient methods to be acquainted with the types of microbes present in soil, and to determine the functional performance of the overall microbial groups in situ. This study aims to investigate the combined uses of species richness and diversity as well as to estimate the combinatorial effect of species richness and diversity in order to understand their role and distribution in their habitat. To achieve this objective a study was designed targeting the rhizosphere of Jatropha curcas L. which were planted in various soil conditions on five distinctive sites of Gujarat state (India). These sites were constantly monitored and studied for the species richness and evenness (heterogeneity). The isolates were checked for their PGPR potentials like Phosphate solubilisation, Siderophore production, Indole acetic acid production, ACC deaminase production, HCN production, EPS production and Ammonia production. The results obtained were used to calculate richness, evenness and diversity indices. Results reveal the total heterogeneity in the site of fertile Jatropha rhizosphere (GS4) as well as sodic soil site (GS5) than other three sites. Absence of equitability under the selected and defined condition was also observed in GS4 and GS5 sites. The combinatorial estimates provide the information on their distribution and roles in the habitat. In particular, such an empirical relationship from a single rhizosphere of a distinctive species Jatropha is useful to test diversity predictions in natural sites, and further it can be applied to either by performing trials over larger spatial and temporal scales or by conducting correlational studies of biodiversity gradients.