Abstract
The petals of cypress vine (Ipomoea quamoclit) may be red, pink, or white; this difference in colors is due to the presence of varying amounts of pelargonidin-based anthocyanin. In this study, we aimed to elucidate the mechanism that controls anthocyanin accumulation in I. quamoclit petals at the molecular level. Pelargonidin was not detected in unhydrolyzed extracts of petals of the white-flowered I. quamoclit but was detected in hydrolyzed extracts; this indicates that leucopelargonidin, a precursor of pelargonidin, is synthesized in the petals of the white-flowered I. quamoclit. In petals of the white-flowered I. quamoclit, anthocyanidin synthase (ANS) expression was not detected, whereas dihydroflavonol 4-reductase (DFR) and flavanone 3-hydroxylase (F3H) expression was detected. Moreover, all progenies obtained by interspecies crossing between white-flowered I. quamoclit and yellow-flowered I. hederifolia, which lacks DFR expression, contained pelargonidin in their petals. These results suggest that pelargonidin was produced in the petals of the progenies by complementary expression of each gene.
