Assessment of phosphate solublizing bacterial strains and their mutants with enhanced phosphate solubilization in relation to green gram (Vigna radiata)

Phosphorus plays an important role in plant metabolism by supplying energy required for metabolic processes. Two phosphate solubilizing bacteria (PSB), 25 MRP and 33 MRP, were taken in this study. On the basis of morphological, physiological and biochemical properties, these PSB were tentatively identified as Pseudomonas sp. Tn-5 derived mutants of 35 MRP and 33 MRP were obtained with altered phosphate solubilizing ability by using E. coli strain S17-1. Highest phosphate solubilization and maximum drop in pH were found with 33 MRP-246 mutant. Under pot house conditions maximum plant dry biomass was observed with 33 MRP-246 with URP at 60 DAS. The highest phosphorus uptake at 30 DAS, 45 DAS and 60 DAS was observed when 25 MRP-145 was inoculated with URP. The PSB/mutant count in green gram rhizopshere decreased at 60 DAS as compared to 30 DAS and 45 DAS. Better performance with low phosphate solubilizing mutants such as 25 MRP-15 and 33 MRP-45 in relation to plant dry weight indicated that some other metabolites may also be involved in plant growth promotion.