Exploration of phytate-mineralizing bacteria with multifarious plant growth-promoting traits

Phytate-mineralizing bacteria (PMB) with plant growth-promoting activity can be considered as a potential biofertilizer for plant nutrition. PMB catalyzes the conversion of insoluble sugar phosphates, inositols, nucleic acids, phospholipids, nucleotides, phytate, and phytin into soluble forms that can be assimilated by plants. The present study aimed to isolate potential PMB from rhizospheric soils and to study their plant growth-promoting potential for the possible development of a potential phosphobacterium biofertilizer. For this purpose, 34 PMB isolates were isolated that showed potent phytate-mineralizing potential. These isolates were tested for their potential to solubilize tricalcium phosphate (TCP) and for various other plant growth-promoting activities. Significant differences were found among the isolates with regard to phytate mineralization and other plant growth-promoting characteristics. The bacterial isolates biochemically identified as Bacillus, Paenibacillus, Arthrobacter, and Burkholderia exhibited high/medium P solubilization, medium/high phytohormone production, and medium/low siderophore and ammonia production. Among all these isolates, isolate A14 (Burkholderia cenocepacia strain FDAARGOS_7) was the promising isolate with high TCP solubilization, medium phytate mineralization, high enzyme production, medium/high phytohormone production, and medium ammonia production. This strain also showed nitrogen fixation activity, zinc solubilizing potential, potassium solubilization, ACC deaminase production, and catalase production. Hence, it can be concluded that B. cenocepacia can be the potential candidate for biofertilizer development. Future studies are planned for exploring the role of PMB in biofertilizer formulations.