The Influence of Physicochemical Parameters on Phosphate Solubilization and the Biocontrol Traits of Pseudomonas aeruginosa FP6 in Phosphate-Deficient Conditions

摘要

Phosphorous deficiency is a major constraint to crop production due to the rapid binding of the applied phosphorous into fixed forms making it not available to the plants. The aim of this study is to isolate phosphate solubilizing bacteria, and assess their effect on the growth of cowpea plant. When tested for its phosphate solubilizing potential, Pseudomonas aeruginosa FP6, a known biological control agent against several phytopathogens, showed 52.38 % solubilizing efficacy. P. aeruginosa FP6 showed optimum phosphate solubilization with glucose (181.75 μg/ml) and ammonium sulphate (184.75μg/ml). The presence of soluble phosphates, with different concentrations of KH2PO4 supplemented in Pikovskaya agar media (PVK), suppressed tri-calcium phosphate (TCP) solubilization activity by FP6. When grown on Tris buffered phosphate medium P. aeruginosa FP6 showed reduction in biocontrol traits except hydrogen cyanide (HCN) production. In pot experiments P. aeruginosa FP6 inoculation with TCP soil amendment (100 mg/ kg) showed significant increase in biometric parameters suggesting that the application of P. aeruginosa FP6 along with the right dose of a phosphate fertilizer could be considered as a sustainable substitute to a higher dose of a phosphorus fertilizer for the cowpea cultivation.