Instituto Valenciano de Investigaciones Agrarias (IVIA), E-46113 Moncada, Valencia, Spain.
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, E-46022, Valencia, Spain.
Sci Rep. 2020 Feb 26;10(1):3543. doi: 10.1038/s41598-020-60635-w.
MBW protein complexes containing MYB, bHLH and WD40 repeat factors are known transcriptional regulators of secondary metabolites production such as proanthocyanidins and anthocyanins, and developmental processes such as trichome formation in many plant species. DkMYB2 and DkMYB4 (MYB-type), DkMYC1 (bHLH-type) and DkWDR1 (WD40-type) factors have been proposed by different authors to take part of persimmon MBW complexes for proanthocyanidin accumulation in immature fruit, leading to its characteristic astringent flavour with important agronomical and ecological effects. We have confirmed the nuclear localization of these proteins and their mutual physical interaction by bimolecular fluorescence complementation analysis. In addition, transient expression of DkMYB2, DkMYB4 and DkMYC1 cooperatively increase the expression of a persimmon anthocyanidin reductase gene (ANR), involved in the biosynthesis of cis-flavan-3-ols, the structural units of proanthocyanidin compounds. Collectively, these data support the presence of MBW complexes in persimmon fruit and suggest their coordinated participation in ANR regulation for proanthocyanidin production.
MBW 蛋白复合物包含 MYB、bHLH 和 WD40 重复因子，是许多植物物种中次生代谢产物如原花青素和花青素以及发育过程如毛状体形成的转录调控因子。不同作者提出 DkMYB2 和 DkMYB4（MYB 型）、DkMYC1（bHLH 型）和 DkWDR1（WD40 型）因子参与柿 MBW 复合物参与未成熟果实中原花青素的积累，导致其具有重要农艺和生态效应的特征性涩味。我们通过双分子荧光互补分析证实了这些蛋白质的核定位及其相互物理相互作用。此外，DkMYB2、DkMYB4 和 DkMYC1 的瞬时表达协同增加了参与顺式黄酮-3-醇生物合成的柿花色苷还原酶基因（ANR）的表达，顺式黄酮-3-醇是原花青素化合物的结构单元。总之，这些数据支持柿果实中存在 MBW 复合物，并表明它们协调参与 ANR 调节以产生原花青素。
