The Molecular Mechanism Underlying Anthocyanin Metabolism in Apple Using the MdMYB16 and MdbHLH33 Genes
The Molecular Mechanism Underlying Anthocyanin Metabolism in Apple Using the MdMYB16 and MdbHLH33 Genes
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利用 MdMYB16 和 MdbHLH33 基因研究苹果花青素代谢的分子机制
DOI：
10.1007/s11103-017-0601-0
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发表时间：
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影响因子：
5.1
通讯作者：
Xuesen Chen
中科院分区：
文献类型：
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作者：
Haifeng Xu;Nan Wang;Jingxuan Liu;Changzhi Qu;Yicheng Wang;Shenghui Jiang;Ninglin Lu;Zongying Zhang;Xuesen Chen
关键信息MdMYB 16形成同源二聚体，并通过其C-末端阻遏物直接抑制花青素苷的合成。在过量表达MdMYB 16的愈伤组织中过量表达MdbHLH 33，减弱了MdMYB 16对花青素合成的抑制作用。MdMYB 16与MdbHLH 33相互作用。摘要花青素是一种强抗氧化剂，在预防心血管疾病、癌症和糖尿病中起着关键作用。新疆野苹果种质资源对花色苷代谢研究具有重要意义。到目前为止，只有有限的研究已经审查了负调控机制的基础花青素在苹果中的合成。本文以成熟红脆1-5苹果（M.结果表明，MdMYB 16蛋白具有一个抑制蛋白的序列和一个bHLH结合基序。在红肉愈伤组织中过量表达MdMYB 16或不含bHLH结合序列的MdMYB 16（LBSMdMYB 16）抑制了MdUFGT和MdANS的表达和花青素的合成。然而，在红肉愈伤组织中过量表达不含Escherichia coli序列的MdMYB 16（LESMdMYB 16）对花青素苷没有抑制作用。酵母单杂交实验表明，MdMYB 16和LESM dMYB 16分别与MdAN和MdUFGT的启动子相互作用。酵母双杂交、pull-down和双分子荧光互补实验表明，MdMYB 16与MdbHLH 33形成同源二聚体并相互作用，而LBSMdMYB 16不能与MdbHLH 33相互作用。我们在过量表达MdMYB 16的愈伤组织中过量表达了MdbHLH 33，发现它减弱了MdMYB 16对花色素苷合成的抑制作用。总之，这些结果表明，MdMYB 16和MdbHLH 33可能是控制花青素生物合成途径的调控网络的重要组成部分。
Key messageMdMYB16 forms homodimers and directly inhibits anthocyanin synthesis via its C-terminal EAR repressor. It weakened the inhibitory effect of MdMYB16 on anthocyanin synthesis when overexpressing MdbHLH33 in callus overexpressing MdMYB16. MdMYB16 could interact with MdbHLH33.AbstractAnthocyanins are strong antioxidants that play a key role in the prevention of cardiovascular disease, cancer, and diabetes. The germplasm ofMalus sieversiif.neidzwetzkyanais important for the study of anthocyanin metabolism. To date, only limited studies have examined the negative regulatory mechanisms underlying anthocyanin synthesis in apple. Here, we analyzed the relationship between anthocyanin levels andMdMYB16expression in mature Red Crisp 1–5 apple (M. domestica) fruit, generated an evolutionary tree, and identified an EAR suppression sequence and a bHLH binding motif of theMdMYB16protein using protein sequence analyses. Overexpression ofMdMYB16orMdMYB16without bHLH binding sequence (LBSMdMYB16) in red-fleshed callus inhibitedMdUFGTandMdANSexpression and anthocyanin synthesis. However, overexpression ofMdMYB16without the EAR sequence (LESMdMYB16) in red-fleshed callus had no inhibitory effect on anthocyanin. The yeast one-hybrid assay showed that MdMYB16 and LESMdMYB16 interacted the promoters ofMdANSandMdUFGT, respectively. Yeast two-hybrid, pull-down, and bimolecular fluorescence complementation assays showed that MdMYB16 formed homodimers and interacted with MdbHLH33, however, the LBSMdMYB16 could not interact with MdbHLH33. We overexpressedMdbHLH33in callus overexpressingMdMYB16and found that it weakened the inhibitory effect ofMdMYB16on anthocyanin synthesis. Together, these results suggested that MdMYB16 and MdbHLH33 may be important part of the regulatory network controlling the anthocyanin biosynthetic pathway.