PDF(Pubmed)
Abstract：
MYB transcription factors have been linked to anthocyanin synthesis and various color phenotypes in plants. In apple, MYB10 confers a red-flesh phenotype due to a minisatellite insertion in its R6 promoter, but R6:MYB10 genotypes exhibit various degrees of red pigmentation in the flesh, suggesting the involvement of other genetic factors. Here, it is shown that MdWRKY10, a transcription factor identified via DNA pull-down trapping, binds to the promoter of MdMYB10 and activates its transcription. MdWRKY10 specifically interacts with the WDR protein MdTTG1 to join the apple MYB-bHLH-WDR (MBW) complex, which significantly enhances its transcriptional activation activity. A 163-bp InDel detected in the promoter region of the alleles of MdWRKY10 in a hybrid population of identical heterozygous genotypes regarding R6 by structural variation analysis, contains a typical W-box element that MdWRKY10 binds to for transactivation. This leads to increased transcript levels of MdWRKY10 and MdMYB10 and enhanced anthocyanin synthesis in the flesh, largely accounting for the various degrees of flesh red pigmentation in the R6 background. These findings reveal a novel regulatory role of the WRKY-containing protein complex in the formation of red flesh apple phenotypes and provide broader insights into the molecular mechanism governing anthocyanin synthesis in plants.
摘要：
MYB转录因子已与植物中的花青素苷合成和各种颜色表型有关。在苹果，MYB10由于其R6启动子中的小卫星插入而赋予红肉表型，但是R6：MYB10基因型在肉中表现出不同程度的红色色素沉着，提示其他遗传因素的参与。这里,它显示了MdWRKY10，一种通过DNA下拉捕获鉴定的转录因子，与MdMYB10的启动子结合并激活其转录。MdWRKY10与WDR蛋白MdTTG1特异性相互作用，加入苹果MYB-bHLH-WDR（MBW）复合物，显着增强其转录激活活性。通过结构变异分析，在有关R6的相同杂合基因型的杂种种群中，在MdWRKY10等位基因的启动子区域中检测到163bp的InDel，包含MdWRKY10结合用于反式激活的典型W-box元素。这导致MdWRKY10和MdMYB10的转录水平增加，并增强果肉中花青素的合成，在很大程度上解释了R6背景中不同程度的肉红色色素沉着。这些发现揭示了含WRKY的蛋白质复合物在红肉苹果表型形成中的新调节作用，并为控制植物花色苷合成的分子机制提供了更广泛的见解。
