Co Application of Metal Oxide Nanoparticles and Plant Growth Promoting Rhizobacteria on the Growth of Groundnut Plant Arachis hypogaea L

Abstract

newlineGroundnut (Arachis hypogaea L.) is an essential oilseed crop that plays a pivotal role in global agriculture and food security. However, its productivity is often restricted by minimal nutrient uptake, environmental stress, and dependency on chemical fertilizers. This study investigates an innovative, sustainable approach to enhance groundnut growth and productivity by integrating plant growth-promoting rhizobacteria (PGPR) and zinc oxide nanoparticles (ZnO NPs). The research aims to explain the synergistic effects of these biotic and abiotic agents on plant growth, and nutrient assimilation, laying a foundation for eco-friendly agricultural practices. newlineRhizospheres soil samples from groundnut fields in Saurashtra, Gujarat, were collected and analyzed. A total of 84 rhizobacterial isolates were screened for their ability to synthesize plant growth-promoting (PGP) compounds, including indole-3-acetic acid (IAA), ammonia, hydrogen cyanide (HCN), gibberellins, and phosphate-solubilizing activity. The most promising isolates were identified as Priestia megaterium (RGKP3), Bacillus haynesii (RG12), and Pseudomonas songnenensis (RG8) based on 16S rRNA sequencing and Gram staining. These strains demonstrated robust plant growth promoting (PGP) traits, contributing to root growth, nutrient availability, and stress mitigation. newlineZnO NPs were synthesized using the sol-gel method with zinc acetate as the precursor. Advanced analytical techniques, including UV-visible spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM), were employed to characterize the crystalline structure, morphology, and optical properties of the nanoparticles. A concentration of 400 ppm ZnO NPs was determined as optimal for biological applications, ensuring compatibility with PGPR strains without inhibiting bacterial growth. newlineThe compatibility and synergistic effects of PGPR strains and ZnO NPs were assessed through growth curve analyses and seed priming