Growth enhancement of rice (Oryza sativa) by phosphate solubilizing Gluconacetobacter sp. (MTCC 8368) and Burkholderia sp. (MTCC 8369) under greenhouse conditions

Two indigenous rhizospheric phosphate solubilizing isolates PSB 12 identified as Gluconacetobacter sp. (MTCC 8368) and PSB 73 identified as Burkholderia sp. (MTCC 8369) were examined for their growth enhancement potential of rice (Jyothi PTB 39) under pot culture assays. The results showed significant impact on microbial count and PSB population, phosphatase and dehydrogenase activity, available phosphorous in the soil, plant nutrient uptake and yield parameters. Gluconacetobacter sp. + RP60 treatment (30.96 µg PNP g-1 soil) retained highest phosphatase activity whereas Gluconacetobacter sp. + Burkholderia sp. + RP60 treatment recorded maximum dehydrogenase activity (38.88 µg TPF g-1 soil) after 60 days of treatment. The treatments Burkholderia sp. + RP60 and Gluconacetobacter sp. + RP60 produced comparable amount of P and these treatments were statistically at par throughout the growth period. Highest nutrient uptake and yield was noted in Gluconacetobacter sp. + Burkholderia sp. + RP60 treatment. A positive synergistic interaction between strains of Gluconacetobacter sp. and Burkholderia sp. has been noticed for their plant growth promotion activity. These strains could be of potential to develop as biofertilizers after testing their performance under field conditions either alone or as components of integrated nutrient management systems.