Repression of MYBL2 by Both microRNA858a and HY5 Leads to the Activation of Anthocyanin Biosynthetic Pathway in Arabidopsis

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• 作者：Yulong Wang¹ ; ² ; Yiqing Wang¹ ; ² ; Zhaoqing Song¹ ; Huiyong Zhang¹ ; ^{huiyong.zhang@henau.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：anthocyanin ; MYBL2 ; translational repression ; miR858a ; HY5
• 刊名：Molecular Plant
• 出版年：2016
• 出版时间：10 October 2016
• 年：2016
• 卷：9
• 期：10
• 页码：1395-1405
• 全文大小：1329 K

文摘

Extensive studies in various plants show that the anthocyanin biosynthetic process is affected by environmental factors and regulated by many transcription factors through sophisticated regulatory networks. However, it remains largely unclear about the roles of microRNA in this process. Here, we demonstrate that miR858a is a positive regulator of anthocyanin biosynthesis in Arabidopsis seedlings. Overexpression of miR858a enhances the accumulation of anthocyanins, whereas the reduced miR858a activity results in low levels of anthocyanins in STTM858 transgenic plants. We found that miR858a inhibits the expression of MYBL2, a key negative regulator of anthocyanin biosynthesis, by translational repression. In addition, ELONGATED HYPOCOTYL 5 (HY5) was shown to directly bind the MYBL2 promoter and represses its expression via specific histone modifications. Interestingly, we found that miR858a exhibits light-responsive expression in an HY5-dependent manner. Together, these results delineate the HY5-MIR858a-MYBL2 loop as a cellular mechanism for modulating anthocyanin biosynthesis, suggesting that integration of transcriptional and posttranscriptional regulation is critical for governing proper anthocyanin accumulation in response to light and other environmental factors.