Nanoscale zinc for sustainable groundnut growth: an eco-conscious molecular approach

Nanotechnology and transcriptomics are revolutionizing agriculture by improving sustainability and efficiency. Nanoparticles facilitate the slow release of nutrients for better crop absorption, while transcriptomic analysis uncovers gene expression changes. In a comparative study of zinc-responsive groundnut using bulk ZnSO4 and zinc oxide nanoparticles (nano ZnO), zinc nanoparticles were synthesized from ZnSO4 via a precipitation method. Characterization included particle size analysis (67.5 nm), zeta potential, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and fourier-transform infrared spectroscopy. RNA was isolated from leaf samples treated with either bulk ZnSO4 or nano ZnO after seed treatment and two foliar sprays over 73 days. Transcriptome sequencing with the Oxford Nanopore Sequencer enabled de novo annotation and differential gene expression analysis. In the bulk ZnSO4 versus control comparison, 971 contigs were identified, revealing 792 significant differentially expressed genes (DEGs). For nano ZnO, 971 contigs were also found, with 851 significant DEGs. Pathway network analysis highlighted isoprene biosynthesis as crucial for promoting plant growth and enhancing yield by altering photosynthesis and secondary metabolites. Key genes, DXR and DBR, involved in the isoprene biosynthetic pathway, were identified as vital for isoprene production and zinc metabolism. DBR facilitates redox reactions crucial for producing isoprene precursors and maintaining zinc homeostasis by supporting the function of zinc-containing proteins. Meanwhile, DXR, as a key enzyme in the MEP pathway, links isoprene production to zinc-dependent metabolic processes. Overall, this study suggests that nano-form zinc application enhances the isoprene biosynthetic pathway, leading to improved plant growth and resilience.