title: Repression of MYBL2 by Both microRNA858a and HY5 Leads to the Activation of Anthocyanin Biosynthetic Pathway in Arabidopsis.
abstract: 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.
authors.affiliation: State Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, College of Life Science, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, College of Life Science, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Yiqing
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, College of Life Science, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Zhaoqing
authors.initials: Z
authors.lastname: Song
authors.affiliation: State Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, College of Life Science, Henan Agricultural University, Zhengzhou 450002, China. Electronic address: huiyong.zhang@henau.edu.cn.
authors.forename: Huiyong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000872:Anthocyanins / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; C103684:AtmybL2 protein, Arabidopsis; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C109254:HY5 protein, Arabidopsis; D035683:MicroRNAs; C000602913:Mirn858 microRNA, Arabidopsis; D009687:Nuclear Proteins; D014157:Transcription Factors
keywords: HY5; MYBL2; anthocyanin; miR858a; translational repression