Abstract
Although a major cue inducing anthocyanin synthesis is light, other factors are necessary to accumulate large amount of anthocyanin. Sugar accumulation enhances anthocyanin synthesis in flower, but there is restricted information about sugar-inducible anthocyanin biosynthesis in vegetative tissues. We developed an anthocyanin induction system by sugar using detached hypocotyls of radish and investigated difference in anthocyanin production between species. Sucrose (175 mM) was the strongest inducer of anthocyanin synthesis in red radish hypocotyls. Glucose and fructose also induced the synthesis, whereas mannose and 3-O-methylglucose did not. Expression of anthocyanin biosynthetic genes (CHS, CHI, F3H, DFR, and ANS) was promoted by sucrose in red radish. The promotion, however, was suppressed in white radish. These results suggest that a portion of signal transduction in anthocyanin induction by sugar may be inactivated in the white radish.
