Efficacy evaluation of newly isolated zinc solubilizing bacteria for their potential effect on maize (Zea mays L.) under zinc deficient soil conditions

Zinc solubilizing bacteria (ZSB) induces the conversion of fixed and unavailable soil zinc to readily available zinc contributes plant zinc nutrition and fortification. The present research intended to determine the screening of plant growth-promoting (PGP) traits of potent ZSB, biochemical and molecular characterization of ZSB, and assessment of potent ZSB for crop yield at the field level. Therefore, in the present study, molecular and functional characterization of native ZSB isolates was done to examine their response to plant growth performance and yield, mobilization of zinc, and acquisition by maize plants. Zinc solubilizing bacterial isolates namely, ZSB1, and ZSB 17 were solubilized insoluble zinc namely, ZnCO3, ZnO, Zn-3(PO4)(2) and significantly induced growth performance of maize crop at field conditions. A biochemical study revealed that both ZSB isolates were positive for catalase and urease production. Isolates ZSB1 & ZSB17 showed different PGP attributes like production of Indole-3-acetic acid (IAA), siderophore, NH3, and HCN. Both isolates were solubilized phosphate, potassium, and silica and showed 1-aminocyclopropane-1-carboxylate (ACC)-deaminase activity. 16S rRNA amplification and sequence study of ZSB1 and ZSB17 revealed that both the isolates were Cupriavidus sp. and Pantoea agglomerans, respectively, and novel. The results elucidated from pot studies demonstrated that both ZSB1 & ZSB17 were the more suitable isolates than other ZSB isolates, and these isolates were further tested for field studies. Cupriavidus sp. and Pantoea agglomerans strains increased Zn-translocation toward grains and yield of Maize (cv: P3441) by 19.01% and 17.64%, respectively. We conclude that the novel indigenous ZSB strains substantially heightened zinc mobilization, the yield of maize crop, restore soil health, and can be suitable for biofortification and biofertilizers technology.