Abstract
While the wild-type Japanese morning glory (Ipomoea nil) exhibits blue flowers with red stems, due to anthocyanin pigmentation, and produces dark-brown seeds, the white-flower mutants c-1 and ca display dark-brown seeds with red stems and ivory seeds with green stems, respectively. We have characterized the tissue-specific expression of three R2R3-MYB genes, three bHLH genes, and two WDR genes in I. nil. Subsequently, we have shown that the c-1 and ca mutations are frameshift mutations caused by a 2-bp deletion and 7-bp insertions in the genes for the R2R3-MYB and WDR transcriptional regulators designated as InMYB1 and InWDR1, respectively. In addition to the defects in flower, stem, and seed pigmentations, we also found that the ca mutants show reduced trichome formation in seeds, which is a novel epidermal traits associated with the WDR transcriptional factor.
