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

Abstract

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.

Tricalcium phosphate solubilization and nitrogen fixation by newly isolated Aneurinibacillus aneurinilyticus CKMV1 from rhizosphere of Valeriana jatamansi and its growth promotional effect

“…Biocontrol potential of a PGPR was associated with production of number of secondary metabolites and antibiotics, siderophore production and HCN production were some of them. 29 , 30 Isolate CKMV1 showed siderophore production (61.60%) along with HCN production. Along with this it also showed antifungal activity against different fungal pathogens of tomato, viz., F. oxysporum (64.3%), R. solani (91.6%), S. rolfsii (93.6%), Phytophthora spp.…”

“…Biocontrol potential of a PGPR was associated with production of number of secondary metabolites and antibiotics, siderophore production and HCN production were some of them 29, 30. Isolate CKMV1 showed siderophore production (61.60%) along with HCN production.…”

Bacillusspecies in soil as a natural resource for plant health and nutrition

“…A stress‐tolerant isolate CB 8 A identified as B. subtilis was reported to solubilize 806 mg l −1 of phosphate with gluconic acid and citric acid detected as major organic acids. The strain is special in its ability to solubilize P at wide range of temperature and pH (Mehta et al ). Three species of Bacillus viz., B. megaterium , B. subtilis and B. cereus were tested for solubilization of phosphorus in the substrates like poultry bones, fish bones and ash.…”

Comprehensive assessment of growth parameters for screening endophytic bacterial strains in Solanum lycopersicum (Tomato)

“…Pseudomonas sp., Burkholderia cepacia produce gluconic acid to solubilize inorganic phosphate and make it readily available for the host plants ( Goldstein, 1994 ). Bacillus subtilis CB8A produce oxalic acid, gluconic acid, formic acid, 2-ketogluconic acid, citric acid, and fumaric acid which are involved in mineral solubilisation ( Mehta et al., 2013 ). The organic acids decrease the pH and form complex with metal ions of insoluble phosphate which assists the process of solubilzation.…”