Characterization of Phosphate solubilising bacteria in saline soil of Odisha Coast line and their role in adaptation strategies to saline stress in crop plant

Abstract

The present study was conducted to isolate phosphate solubilising bacteria from newlinerhizospheric saline soils of coastal Odisha, India and evaluate their phosphate newlinesolubilising ability. Total of five phosphate solubilizing bacteria isolated based on the newlinehalo zone formation (SI 2.63-3.14) on Pikovaskaya s agar medium and were newlinecharacterized based on biochemical and molecular characteristics as Bacillus subtilis newline(B1), B. megaterium (B2), B. acideceler (P1), Sphingomonas paucimobilis (P2) and newlineKocuria kristinae (P6). Strains were further screened for their efficacy to solubilize newlineinsoluble phosphate in Pikovaskaya s broh. The inorganic phosphate released by PSB newlineranged from 18.532 to 38.250µg/ml with decreasing the medium pH up to 3.9. Glucose newlinewas found to be the best carbon source for Bacillus subtilis, B. acideceler, newlineSphingomonas paucimobilis and Kocuria kristinae whereas mannitol for newlineB. megaterium. All the five PSB isolates solubilised more phosphate in presence newlineammonium sulphate at 30o newlineC and pH 7.0. and tolerated NaCl concentration from 0.05% newlineto 0.07%. Acid phosphatase activity for PSB were recorded 84.237-98.658µmol/min. newlineGlucose was found to be the best carbon source for Bacillus subtilis, B. acideceler, newlineSphingomonas paucimobilis and Kocuria kristinae whereas mannitol for newlineB. megaterium. All the five PSB isolates solubilised more phosphate in presence newlineammonium sulphate at 30o newlineC. The amount of IAA produced by bacterial isolates ranged newlinefrom 5.11 to 7.93µg/ml in nutrient broth supplemented with 2mg/ml at 48h of newlineincubation. The IAA was partially purified confirmed by TLC with Rf value 0.85, same newlineas standard. The optimum temperature for IAA production was 30o newlineC. The maximum newlinephosphate solubilisation efficiency, inorganic phosphate solubilisation, acid newlinephosphatase activity and IAA production ability was recorded by B. megaterium newline213.7%, 38.250µg/ml, 98.658µmol/min and 7.93µg/ml respectively, which was newlinesignificantly superior to the other strains.