Exploring genetic determinants of silver oxide nanoparticle-induced seed priming for drought tolerance in wheat

Drought occurring at the early developmental stages results in a reduction of the wheat growth and development performance, hence, yield and grain quality reduction. Therefore, understanding the role of seed priming through the application of hydropriming and nanopriming using silver nanoparticles (AgNPs) is highly important in response to drought stress. This study aims to detect the natural phenotypic variation of the traits related to germination parameters, seedling characteristics, and seed biomass, as well as the chlorophyll content under both control and drought treatments. Evaluating wheat accessions response to seed priming, including hydropriming and nanopriming using 50 ppm AgNPs. Under drought stress, a highly significant increase was detected for germination-related traits, seedling, and biomass parameters in wheat seeds exposed to silver nanopriming as compared to the control treatment. Under nano-primed seed (AgNPs) conditions, root length showed a positive correlation with all traits under drought stress, suggesting a strong relationship between root length and all germination and seedling parameters resulting in wheat experiencing tolerance to water shortage conditions. Based on genome wide association study (GWAS) and linkage disequilibrium (LD) outputs, a total of 261 single nucleotide polymorphism (SNP) markers were detected for all of the studied traits under both control and drought conditions. Interestingly, twenty reliable genomic regions with several hotspots of significant SNP markers were discovered inside high LD regions. Markedly, chromosome 1B showed high significant marker (Tdurum_contig11896_550) at position 581,201,755 bp. Within this region, the candidate gene TraesCS1A02G049700 encodes zinc finger-like domains superfamily that controls the variation of chlorophyll content under CHP, CUP, and DNP. The accessions carrying T allele showed higher chlorophyll content under CUP, CHP, and DNP than the accessions carrying C allele, suggesting the positive selection for accessions carrying T allele in breeding programs under drought stress conditions. The identification of these genetic factors opens new pathways for the development of wheat cultivars to withstand water scarcity.