Characterization and Evaluation of P Solubilizing Bacteria from Forest Soils for Plant Growth Promotion

In the present study, four potential P solubilizing isolates viz. Bacillus megaterium NGNB17 and B. gingsengisoli JB1, Kluyvera cryocrescens JBP1 and Serratia nematodiphila NGNB2 were isolated and characterized from the soils of tropical forests of India. All isolates could solubilize > 200 mg L^-1 Udaipur Rock phosphate with NGNB2 having highest (712 mg L^-1) solubilization capacity. NGNB17 showed highest acid phosphatase activity (94.5 U L^-1) while NGNB2 showed highest alkaline phosphatase activity (24.0 U L^-1). JBP1 was the only isolate positive for IAA production, siderophore production and K solubilization. All the isolates showed significant improvement in growth of Maize, Chickpea and Wheat under pot trials, but NGNB17 and JBP1 had more pronounced effect. When evaluated on Wheat (HD2967) under field conditions along with Pseudomonas striata, Paenibacillus tylopili and Aspergillus awamori as positive checks, JBP1 performed at par with them and could save 50% of phosphatic fertilizer to produce statistically comparable yield as obtained for full dose of fertilizer. This is the first report of Kluyvera cryocrescens being demonstrated for its plant beneficial effects at field level emphasizing its use as bioinoculant. The present study is also the first report for plant growth promoting activity of Bacillus gingsengisoli.

The online version contains supplementary material available at https://doi.org/10.1007/s12088-025-01540-6.