Synergistic Roles of Zinc Oxide Nanoparticle and Plant Growth Promoting Rhizobacteria on the Growth of Groundnut ( Arachis hypogaea L. )

A comprehensive study was conducted to explore the plant growth-promoting potential of soil microbes and the synergistic effects of nanoparticles on plant growth. A total of 84 PGPR isolates were obtained from soil samples in Saurashtra, Gujarat, India, with three strains— Pseudomonas songnenensis, Bacillus haynesii , and Priestia megaterium— selected for further research due to their positive results in promoting plant growth under in vitro conditions. The efficiency of PGPR was studied with the co-application of zinc oxide (ZnO) nanoparticles. ZnO NPs were produced via the sol-gel process and characterized through UV-visible spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The experimental setup was aimed to study the effect of three effective microbial strains with an optimal concentration of ZnO nanoparticles (400 ppm) on the growth of groundnut plants. The co-application of PGPR and ZnO NP displayed a significant increase in the physic-chemical characteristics of the plants. The cumulative effect of isolate RGKP3+ZnO NPs treatment showed maximum carotenoid content (~ 77.4 pg/g), while chlorophyll content was 24.80 mg/g. The present study emphasized the potential of co-application of PGPR and ZnO nanoparticles for sustainable agriculture and improving crop yields in eco-friendly manner.