How does barley make vitamin E?

Vitamin E (tocochromanol) is a group of fat-soluble compounds that can help fight against cardiovascular disease and certain cancers. While the way plants create vitamin E is known in dicots, like Arabidopsis, it’s not so well known in monocots. In a paper in Annals of Botany Zeng and colleagues use CRISPR/Cas9 to knock out genes to see how the genes affect vitamin E biosynthesis.

Zeng and colleagues created HvHGGT and HvHPT mutants to see what differences knocking out the genes made. “Because the knockout of HvHPT reduced approximately 50 % of tocopherol content compared to that of the wild-type grains, HvHPT is partly responsible for tocopherol biosynthesis in barley, implying that potential HvHPT homologues or other genes might be involved in tocopherol production in barley,” write the authors in their paper.

“The results suggested that HvHGGT cannot replace the tocopherol biosynthesis function of HvHPT in barley. Our study functionally validated that HvHGGT is the only committed gene to produce tocotrienols, whereas HvHPT is partly responsible for tocopherol biosynthesis in barley. Hence, the vitamin E biosynthetic pathway has diverged between dicots and monocots, and the HPT homologue (HORVU2Hr1G117600) or other biosynthesis pathway-related genes may participate in the metabolic fluxes of tocopherol accumulation in barley and other monocots.”