Anthocyanin production by over-expression of grape transcription factor gene VlmybA2 in transgenic tobacco and Arabidopsis
An myb-related transcription factor gene of the anthocyanin biosynthetic pathway, VlmybA2, from the Kyoho grape (Vitis labruscana) was introduced into tobacco and Arabidopsis under the control of the cauliflower mosaic virus 35S promoter. The 35S:VlmybA2-induced anthocyanin production was prominent in transformed tobacco calli, and the regenerated tobacco plants were completely purple. Except for the color, the transgenic plants were apparently not different from the control plants. During plant growth in pots, the purple color was not uniformly distributed but appeared as patches in the leaves, whereas the flowers showed intense pigmentation. In Arabidopsis, T1 transformants showing two prominent phenotypes: completely purple seedlings and seedlings with green leaves and purple roots. The partially purple seedlings grown in pots produced fertile and viable seeds of two distinguishable colors, purple and brown. VlmybA2 alone, without the aid of other myc-related genes, could induce complete pigmentation in tobacco and Arabidopsis, indicating its potential over other previously used myb- and myc-related genes.