Comparison of diversity and zinc solubilizing efficiency of rhizobacteria obtained from solanaceous crops under polyhouse and open field conditions.

Zinc-solubilizing bacteria (Zn-SB) play a crucial role in regulating soil fertility and plant health by maintaining Zn availability in the rhizosphere. It is uncertain how the Zn-SB population fluctuates across various cultivation systems since varied land-use patterns for agricultural aims may affect microbial activity and plant development effectiveness. The current study aims to examine the Zn-SB potential of various farming systems using Solanum lycopersicum, Solanum melongena , and Capsicum annuum grown in polyhouse soil (PS) and open fields (OF). Only twenty rhizobacterial isolates from PS and two isolates from OF out of 80 showed a strong ability to solubilize Zn, which was evaluated using Atomic Absorption Spectroscopy. Bacterial strain-PS4 solubilized 253.06 ppm of ZnO and produced a high quantity of lactic acid (168.62 g/ml) and acetic acid (470.5 g/ml), whereas bacterial strain OF1 solubilized 16.02 ppm of ZnO by releasing glycolic acid (42.89 g/ml), lactic acid (22.30 g/ml), formic acid (106.03 g/ml), and acetic acid (48.5 µg/ml). Further, in vitro studies demonstrated higher production of auxin, gibberellic acid and siderophore by PS1 as compared to OF1 strain. A large diversity of Zn-SB in the soil was indicated by biochemical analysis, which revealed that isolates belonged to the families Enterobacteriaceae, Bacillaceae, Burkholderiaceae, Streptococcaceae, Paenibacillaceae, Micrococcaceae, Morganellaceae , and Dietziaceae . The isolates PS4 and OF1 were identified as Bacillus cereus and Enterobacter hormaechei , respectively, using 16S rRNA sequencing. The findings show that soil from polyhouses has a greater diversity of Zn-solubilization rhizobacteria than soil from open areas. The findings suggested a potential land-use method for enhancing crop yields by employing microorganisms and polyhouse technology, which could be useful in the future study.