Assessment of zinc-solubilizing bacterial isolates for plant growth promoting traits and water stress tolerance behaviour

Abstract

The present study elucidates the efficiency of zinc solubilization and the plant growth-promoting (PGP) traits exhibited by selected zinc-solubilizing bacterial (ZSB) strains. Qualitative analysis unveils distinct variations in solubilization efficiency, with isolate FMBR110 demonstrating exceptional proficiency in solubilizing zinc from various insoluble sources. PGP traits, encompassing phosphate solubilization, siderophore production, indole-3-acetic acid (IAA) synthesis, exopolysaccharide (EPS) generation, hydrogen cyanide (HCN) emission, and ammonia production are quantified, spotlighting the functional diversity among isolates. Notably, FMAR106 showed the highest phosphate solubilization zone value (2.20 cm), while FMBR110 exceled in siderophore production (4.37 cm halo zone), IAA synthesis (24.09 µg/ml), and stands out as the sole producer of HCN. Furthermore, isolate FMBR110, exhibited remarkable tolerance to water stress, even in high water saturated soil conditions. The study accentuates the importance of selecting ZSB strains tailored to specific water conditions in agriculture, offering promising solutions for sustainable crop production, particularly in high waterstressed regions or flooding conditions.