Characterization of two mutants that affect flower and seed pigmentation in the common morning glory.

Abstract

While the wild type common morning glory (Ipomoea purpurea) displays purple flowers and black seeds, two mutant lines showing white seeds and palely pigmented flowers were found to produce drastically reduced amounts of the transcripts of the IPMYC3 gene, a homologue of the an1 gene for the bHLH transcriptional factor that regulates flower and seed pigmentation in petunia. The genomic sequences revealed that both mutants carry two insertions of transposable elements into the IPMYC3 gene which comprises 8 exons. In one mutant, two copies of Tip100 belonging to the Ac/Ds family are inserted into the second intron and the seventh exon. The other mutant contains two different Mu-related transposable elements in the second exon and the fifth intron. Moreover, the latter mutant appears to carry an additional mutation for flower pigmentation.