Recruitment of cytochrome P450 enzymes for flavone biosynthesis in rice

Abstract

Flavones are flavonoids found extensively in land plants with important physiological functions like UV protection, interactions with other organisms, co-pigmentation in flowers, etc. They are increasingly popular as dietary constituents or supplements due to their health-beneficial properties. In grasses, flavones are predominantly accumulated as C- or O-linked conjugates in vegetative tissues. The enzymology of flavone biosynthesis remained largely elusive until recent years. Our recent work demonstrated the involvement of distinct rice cytochrome P450 enzymes for the biosynthesis pathways of flavone C- and O-linked conjugates. We further revealed the modification of lignin compositions in our flavone mutants. These novel P450 enzymes are highly conserved among grass genomes. They represent good targets to engineer flavones in edible tissues and modify lignin for enhanced biomass utilization.