Polyphasic Characterization of Indigenous Potassium-Solubilizing Bacteria and Its Efficacy Studies on Maize

Potassium (K) helps crop plants to resist biotic and abiotic challenges and plays a vital role in biochemical, metabolic, and physiological processes. Due to intense agricultural practices over the past few decades, the soil K reserve has been observed to be decreasing globally. It is possible to view potassium-solubilizing bacteria (KSB), which uses a number of biological mechanisms to convert potassium from inaccessible forms and make it accessible to crop plants, as a viable method for managing K in soils with low potassium levels. The present study encompasses 44 KSB strains isolated from rhizospheric soils collected from southern Rajasthan, India and characterized based on morphological, biochemical, and molecular profiles. All the isolates exhibited potassium solubilization and were identified using ERIC, BOX, REP PCR, and 16 S rDNA amplification which exhibited significant diversity amongst the strains. A flame-photometric analysis revealed that significant amounts of potassium were released by isolates from muscovite mica on the 21st day of incubation. These KSB strains produced hydrolytic enzymes and plant growth-promoting activities at different environmental stresses. In comparison to the absolute control (control without KSB), maize seedlings grown from bacterized seeds showed an increase in shoot length, root length, leaf number, total chlorophyll content, and the expression of stress-related enzymes. These native strains, which have a variety of advantageous traits, may be able to replace synthetic K fertilizers in order to increase food production while reducing pollution and restoring degraded land for agricultural use.