Related Experiment Video
Updated: Oct 10, 2025
Lignin Down-regulation of Zea mays via dsRNAi and Klason Lignin Analysis
Published on: July 23, 2014
R3-MYB transcription factor LcMYBx from Litchi chinensis negatively regulates anthocyanin biosynthesis by ectopic
Jietang Zhao1, Linhuan Chen1, Anna Ma1
1State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs/Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China.
Abstract:
Anthocyanin accumulation is one of the remarkable physiological changes during fruit ripening. In plants, anthocyanin synthesis is regulated by MYB activators, but the MYB repressors has been recognized recently. Here, we isolated a repressor of anthocyanin synthesis, LcMYBx, from Litchi chinensis Sonn. LcMYBx encoded a typical R3-MYB protein and contained a conserved [D/E]Lx2[R/K]x3Lx6Lx3R motif for interacting with bHLH proteins. Overexpression of LcMYBx in tobacco suppressed anthocyanin accumulation resulting in faded petals from pale-pink to almost white. Gene expression analysis showed the strong down-regulation of endogenous anthocyanin structural and regulatory genes by LcMYBx overexpression. Yeast two-hybrid and bimolecular fluorescence complementation assays indicated that LcMYBx could interact with the transcription factors LcbHLH1 and LcbHLH3. Transient promoter activation assays showed that LcMYBx could inhibit the activation capacity of LcMYB1-LcbHLH3 complex for LcDFR gene. These results suggest that LcMYBx competed with LcMYB1 to LcbHLHs, thus preventing the activation of LcDFR by LcMYB1-LcbHLHs complex and negatively controlling anthocyanin biosynthesis.
