Ferulic acid 5-hydroxylase 1 is essential for expression of anthocyanin biosynthesis-associated genes and anthocyanin accumulation under photooxidative stress in Arabidopsis.

摘要

Anthocyanins are important for preventing photoinhibition and photodamage. By comprehensive reverse genetic analysis of chloroplast-produced H₂O₂-responsive genes, we isolated here an anthocyanin-deficient mutant under photooxidative stress, which lacked ferulate 5-hydroxylase 1 (FAH1) involved in the phenylpropanoid pathway. Interestingly, the expression of anthocyanin biosynthesis-associated genes was also inhibited in this mutant. These findings suggest that FAH1 is essential for expression of anthocyanin biosynthesis-associated genes and anthocyanin accumulation under photooxidative stress in Arabidopsis. Furthermore, we found that estrogen-inducible silencing of thylakoid membrane-bound ascorbate peroxidase, which is a major H₂O₂-scavenging enzyme in chloroplasts, enhances the expression of FAH1 and anthocyanin biosynthesis-associated genes and accumulation of anthocyanin without any application of stress. Thus, it is likely that chloroplastic H₂O₂ activates FAH1 expression to induce anthocyanin accumulation for protecting cells from photooxidative stress.