Expression of RsMYB1 in chrysanthemum regulates key anthocyanin biosynthetic genes

Background: Several MYB genes belonging to R2R3 MYB transcription factors have been used in several plant species to enhance anthocyanin production, and have shown various expression or regulation patterns. This study focused on the effect of ectopic expression of an RsMYB1 isolated from radish (Raphanus sativa) on chrysanthemum cv. ‘Shinma’. Results: The RT-PCR results confirmed that RsMYB1 regulated the expression of three key biosynthetic genes (CmF3H, CmDFR, and CmANS) that are responsible for anthocyanin production in transgenic chrysanthemum, but were not detected in the non-transgenic line. In all transgenic plants, higher expression levels of key biosynthetic genes were observed in flowers than in leaves. However, the presence of RsMYB1 in chrysanthemum did not affect any morphological characteristics, such as plant height, leaf shape or size, and number of flowers. Furthermore, no anthocyanin accumulation was visually observed in the leaves and floral tissue of any of the transgenic lines, which was further confirmed by anthocyanin content estimation. Conclusion: To our knowledge, this is the first time the role of an MYB transcription factor in anthocyanin production has been investigated in chrysanthemum.