R2R3-MYB transcription factor MYB6 promotes anthocyanin and proanthocyanidin biosynthesis but inhibits secondary cell wall formation in Populus tomentosa
R2R3-MYB transcription factor MYB6 promotes anthocyanin and proanthocyanidin biosynthesis but inhibits secondary cell wall formation in Populus tomentosa
复制标题
R2R3-MYB转录因子MYB6促进毛白杨花青素和原花青素生物合成但抑制次生细胞壁形成
DOI：
10.1111/tpj.14364
复制
发表时间：
2019-08-01
期刊：
影响因子：
7.2
通讯作者：
Luo, Keming
中科院分区：
文献类型：
--
作者：
Wang, Lijun;Lu, Wanxiang;Luo, Keming
The secondary cell wall is an important carbon sink in higher plants and its biosynthesis requires coordination of metabolic fluxes in the phenylpropanoid pathway. In Arabidopsis (Arabidopsis thaliana), MYB75 and the KNOX transcription factor KNAT7 form functional complexes to regulate secondary cell wall formation in the inflorescence stem. However, the molecular mechanism by which these transcription factors control different branches of the phenylpropanoid pathway remains poorly understood in woody species. We isolated an R2R3-MYB transcription factor MYB6 from Populus tomentosa and determined that it was expressed predominately in young leaves. Overexpression of MYB6 in transgenic poplar upregulated flavonoid biosynthetic gene expression, resulting in significantly increased accumulation of anthocyanin and proanthocyanidins. MYB6-overexpression plants showed reduced secondary cell wall deposition, accompanied by repressed expression of secondary cell wall biosynthetic genes. We further showed that MYB6 interacted physically with KNAT7 and formed functional complexes that acted to repress secondary cell wall development in poplar and Arabidopsis. The results provide an insight into the transcriptional mechanisms involved in the regulation of the metabolic fluxes between the flavonoid and lignin biosynthetic pathways in poplar.
