Phosphate solubilisation and plant growth promoting potential by stress tolerant Bacillus sp. isolated from rhizosphere of apple orchards in trans Himalayan region of Himachal Pradesh

Phosphate‐solubilising ability and co‐production of plant growth promoting traits of stress tolerant Bacillus subtilis CB 8 A isolated from apple rhizosphere was tested under in vitro conditions against a wide range of temperature (30–45°C), pH (7–9) and salt (0–5%) stresses. Under the extremes of temperature (45°C), pH ‐9 and salt concentration (5%), production of soluble phosphate, indole acetic acid, siderophore and antifungal activity against Dematophora necatrix were reduced by 71.09%, 75.29%, 90.3% and 88.47%, respectively. Per cent decrease in P‐solubilisation at extreme temperature (45°C) and normal pH (7) without salt concentration was 36.23%; at extreme pH (9) and normal temperature (37°C) without salt concentration was 23.45% and at extreme salt concentration (5%), optimum temperature (37°C) and pH (7) was 36.7%. P‐solubilisation by CB 8 A was inversely correlated with pH ( r = −0.78) and positively correlated with siderophore production ( r = 0.81), indole acetic acid ( r = 0.58) and antifungal activity ( r = 0.63). Gluconic acid (1.43%) and citric acid (0.67%) were detected as major organic acids. P‐solubilisation and nitrogen fixing abilities of B. subtilis CB 8 A were confirmed by amplification of gdh and nif H genes. The ability of CB8A showing plant growth promoting rhizobacteria ( PGPR ) traits at a wide range of temperature, pH and varying salt concentration can be exploited for developing multifunctional biofertiliser in apple orchards.