Host: The Japanese Society of Plant Physiologists
Pages 0139
We reported previously that anthocyanin biosynthesis in gentian flowers is regulated by temporal and spatial expressions of their biosynthetic structural genes. However, no regulatory factor in gentian plants has been reported yet. In Arabidopsis, petunia and snapdragon, MYB and basic Helix-Loop-Helix (bHLH) have been known as the transcriptional factors regulating anthocyanin biosythesis. We isolated each homologue, GtMYB3 and GtbHLH1, from gentian flower cDNA using degenerated PCR technology. Expression profiles of both genes were similar to the accumulation of anthocynin and the expression of their biosynthetic structural genes during flower development. Transient expression assay showed that GtMYB3 and GtbHLH1 could enhance promoter activities of anthocyanin biosynthetic genes when co-expressed. Yeast two-hybrid system showed the interaction between GtMYB3 and GtbHLH1. In addition, some white-flowered gentian cultivars had aberrant GtMYB3 gene by the insertion of transposable elements. These evidences suggested that both GtMYB3 and GtbHLH1 are involved in anthocyanin biosynthesis in gentian flowers.
