Identification and characterization of genes involved in tocochromanol biosynthesis pathway through genomics and transcriptomics in durum and bread wheat

Lipid-soluble plant antioxidants, tocochromanol (tocols for short), are essential for the regulation of lipid peroxidation in chloroplasts and seeds. They are also referred to as Vitamin E. Wheat germ oil contains the highest percentage of tocols among these sources, but the information about the tocol biosynthesis gene is very minimal. Tocols, comprising tocotrienols and tocopherols, are beneficial for human health due to their antioxidant properties. The current research delved into the genome and transcriptome to identify genes involved in tocol biosynthesis in wheat. Ten different structural gene families were identified with a total of 78 isoforms, shedding light on the complex pathway of tocol synthesis. Genes showed distinct domain profiles, exon architectures, tissue localization, regulatory elements, chromosome location, synteny and phylogeny, indicative of their unique function. Differential expressions in 27 isoforms were identified through RNA sequencing of developing seedlings from high tocol (HI8663, HAU105) and low tocol content (NABIMG-9-Blue and PBW621) in durum and bread wheat varieties. This comprehensive approach not only provides insights into the natural diversity of tocol content in wheat but also paves the way for potential enhancements through breeding and genome editing techniques. Increasing tocol content in wheat could have significant implications for human nutrition and health.