Abstract
We prepared transgenic plants that express a chimeric repressor for single-MYB domain protein and attempted to identify those involved in flavonoid biosynthesis by isolating seeds with different color from wild-type. We found that the expression of the chimeric repressor for AtMYBL2 resulted in pale-color seeds. Interestingly, the ectopic expression of AtMYBL2 (35S:AtMYBL2) also induced light color in the seeds. The contents of anthocyanin in leaves both of 35S::AtMYBL2 and 35S::AtMYBL2SRDX transgenic plants were much lower than those of wild type plants. Transient analyses revealed that 6 amino acids at the carboxy-terminal region of AtMYBL2 sufficiently confer the repression activity. Expression of the trancated AtMYBL2 from which a C-termini was remomved, and homozygous AtMYBL2 T-DNA tagged line exhibited an increase of anthocyanin contents in rosette leaves. These data suggests that AtMYBL2 is a negative regulator for flavonoid biosynthesis.
