Overexpression of the Raphanus sativus RsMYB1 using the flower-specific promoter (InMYB1) enhances anthocyanin accumulation in flowers of transgenic Petunia and their hybrids

The generation of transgenic floricultural crops for flower color modification requires a transgene that enhances anthocyanin accumulation and a flower-specific promoter with stable expression throughout flowering stage. Here, the anthocyanin regulatory R2R3-MYB transcription factor (TF) RsMYB1 was placed under the control of the stable flower-specific promoter (InMYB1) to enhance anthocyanin accumulation in Petunia hybrida cv. Mirage Rose. RsMYB1 overexpression with the flower-specific promoter enhanced anthocyanin accumulation only in floral tissues via the upregulation of key anthocyanin biosynthetic genes. The target gene introgression to another Petunia hybrida cv. White Hawaiian lacking anthocyanins also changed the flower color from white to intense pink in the F₁ hybrids by upregulating the biosynthetic genes. Target gene inheritance in the F₂ hybrids also produced diverse flower colors, redder than those of non-inheritance F₂ hybrids. RsMYB1 overexpression using the flower-specific promoter (InMYB1) enhanced anthocyanin levels in the petals of transgenic Petunia and its related hybrids. Thus, this system can be used as a promising tool for intensifying the flower color of other commercially important floricultural crops. In addition, the obtained F₂MW11 and F₂MW12 lines are potential commercial cultivars for the floriculture and landscape industries due to its attractive flower color pattern.