Mapping the path to reveal genomic regions and candidate genes underlying metabolite-mediated wheat adaptation under cadmium stress
摘要
Wheat is one of the most extensively developed grains because it adapts to diverse conditions and environments. Cadmium (Cd) stress can lead to a significant reduction in crop yield and quality. Understanding the genetic associations underlying wheat responses to cadmium stress is important to developing more tolerant wheat varieties using a genome-wide association scan (GWAS). In this study, a core collection of 111 wheat accessions was evaluated under both control and cadmium treatments at the vegetative stage, with several traits, including mineral accumulation, metabolite profiles, and agronomic features, being measured. Our study revealed a highly significant increase in metabolites detected across all wheat accessions in response to Cd treatment. A significant positive correlation was detected between total flavonoids and thousand kernel weight indicating the significant role of metabolites (total flavonoids) through enhanced wheat responses to cadmium stress. Upon GWAS analysis, 71 significant single nucleotide polymorphisms (SNPs) markers were detected at threshold –log 10(p-value) ≥ 5 within the region of linkage disequilibrium (LD). Of these, significant SNP markers were found to be near or inside several candidate genes encoded metabolites that have a potential role in response to heavy metal stress, including cadmium stress through strengthening antioxidant defenses. Interestingly, a highly significant SNP was found at position 581,205,619 bp near the gene TraesCS1B02G383400 that encodes geranyl transferase. Geranyl transferase is an enzyme involved in the biosynthesis of terpenoids, which are important secondary metabolites in plants. In conclusion, the identification of the genetic factors associated with key traits will contribute to the development of improved wheat crop varieties.