Single MYB-type transcription factor AtCAPRICE: a new efficient tool to engineer the production of anthocyanin in tobacco.

The single MYB-type protein, CAPRICE has long been thought to be a positive regulator of root hair development in Arabidopsis thaliana. To further probe the role of AtCPC and how conserved this role is across plant species, the AtCPC gene was constitutively overexpressed in tobacco (Nicotiana tabacum). Here, we show that flowers of transformants overexpressing AtCPC displayed an unexpected defection in pigmentation. A reduction in the level of anthocyanin was detected and the severity of abnormal flavonoid phenotype correlates well with the increased expression level of AtCPC gene. We also found that transcripts of three late biosynthetic genes were substantially down-regulated. Furthermore, AtCPC could interact with other known anthocyanin regulators. Our data suggest that in a heterologous host, AtCPC acts as a repressor of anthocyanin production, from which a new evidence for better understanding of the transcriptional regulation of flavonoid biosynthesis and, an implication for the development of new varieties of tobacco and other commercially important ornamental plants are provided.