Potassium Solubilizing Bacteria Having Antagonistic Effect on Plant Pathogenic Fungi and Inducing Effective Brinjal Seed Germination

The aim of this research was to identify potassium-solubilizing bacteria (KSB) and evaluate their ability to release available potassium (K) from the soil for enhanced plant uptake. After assessing various strains for plant growth-promoting (PGP) traits and potassium-solubilizing effectiveness, five significant strains were selected. Using the BIOLOG system for further identification, it was determined that two of the most effective strains belong to the genus Bacillus. In laboratory conditions, potassium solubilization ranged from 1.89 to 46.52 μg/ml. The most effective strain, Bacillus licheniformis, achieved a potassium solubilization of 46.52 μg/ml, while Bacillus subtilis followed with 40.58 μg/ml. These KSB strains also demonstrated phosphate solubilization, IAA production, and potential for biocontrol against plant pathogenic fungi. In an In vitro experiment with brinjal seeds, three highly efficient KSB isolates (KSB-1, KSB-3, and KSB-20) with strong phosphate solubilizing and antagonistic abilities were tested. Bacillus licheniformis (KSB-1) showed the highest potassium solubilization, increased potassium content in plants, and improved growth parameters, with Bacillus subtilis (KSB-3) showing significant, though slightly lower, effects.