College of Plant Science, Jilin University, Changchun, 130062, Jilin, China.
Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON N5V 4T3, Canada; Department of Biology, Western University, London, ON N6A 3K7, Canada.
Biochem Biophys Res Commun. 2018 Dec 9;507(1-4):324-329. doi: 10.1016/j.bbrc.2018.11.033. Epub 2018 Nov 15.
MYB transcription factors play important roles in the regulation of phenylpropanoid biosynthesis. However, the knowledge regarding the roles of CCA1-like MYBs in phenylpropanoid pathway is limited in plants. Previously, we identified 54 CCA1-like proteins in soybean. In the study, a CCA1-like MYB (GmMYB133) was functionally characterized as a positive regulator in isoflavonoid synthesis. GmMYB133 encodes a 330 aa protein featured with one CCA1 conserved motif. Further analysis indicated that the expression pattern of GmMYB133 was near-perfectly correlated with isoflavonoid accumulation as soybean embryos develop. GmMYB133 over-expression promoted the expression of two key isoflavonoid biosynthetic genes (GmCHS8 and GmIFS2) and increased total isoflavonoid content in hairy roots. Protein-protein interaction assays indicated that GmMYB133 might form hetero- and homodimers with an isoflavonoid regulator GmMYB176 and itself, respectively, while the subcellular localization of GmMYB133 can be altered by its interaction with 14-3-3 protein. These findings provided new insights into the functional roles of CCA1-like MYB proteins in the regulation of phenylpropanoid pathway, and will contribute to the future genetic engineering in the improvement of soybean seed quality.
MYB 转录因子在苯丙烷生物合成的调控中发挥重要作用。然而，关于 CCA1 样 MYB 在苯丙烷途径中的作用的知识在植物中是有限的。以前，我们在大豆中鉴定了 54 种 CCA1 样蛋白。在这项研究中，一种 CCA1 样 MYB（GmMYB133）被功能表征为异黄酮合成的正调控因子。GmMYB133 编码一个 330 个氨基酸的蛋白质，具有一个 CCA1 保守基序。进一步的分析表明，GmMYB133 的表达模式与大豆胚胎发育过程中异黄酮的积累近乎完美相关。GmMYB133 的过表达促进了两个关键异黄酮生物合成基因（GmCHS8 和 GmIFS2）的表达，并增加了毛状根中的总异黄酮含量。蛋白质-蛋白质相互作用分析表明，GmMYB133 可能分别与异黄酮调节剂 GmMYB176 和自身形成异源和同源二聚体，而 GmMYB133 的亚细胞定位可以通过与 14-3-3 蛋白的相互作用而改变。这些发现为 CCA1 样 MYB 蛋白在苯丙烷途径调控中的功能作用提供了新的见解，并将有助于未来通过遗传工程提高大豆种子质量。
