The Grapevine Vegetative Color Locus Encompasses Three Closely Related R2R3-MYB Transcription Factors and Regulates Anthocyanin Synthesis with Different Specificities Compared to the Berry Color Locus

The grape color locus 2 affects anthocyanin pigmentation of vegetative organs. For the genetic transformation of Vitis vinifera cv Maccabeu, the in vitro plantlets were grown for 90 days under light and temperature controlled. For overexpression of the MYB genes in Vitis vinifera cv Maccabeu hairy roots, the cDNA sequences were transferred into the binary vector pH2GW7 by site-specific recombination. The construct were then inserted into Agrobacterium tumefaciens A4 by electroporation and used for the grapevine transformation. The induction and culture of transgenic HRs in grapevine were performed as described by Torregrosa and Bouquet (1997), with modifications reported in Cutanda-Perez et al. (2009).