CsMYB3 and CsRuby1 form an 'Activator-and-Repressor' Loop for the Regulation of Anthocyanin Biosynthesis in Citrus
CsMYB3 and CsRuby1 form an 'Activator-and-Repressor' Loop for the Regulation of Anthocyanin Biosynthesis in Citrus
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CsMYB3 和 CsRuby1 形成“激活剂和阻抑剂”环，用于调节柑橘花青素生物合成
DOI：
10.1093/pcp/pcz198
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发表时间：
2020-02-01
影响因子：
4.9
通讯作者：
Xu, Qiang
中科院分区：
文献类型：
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作者：
Huang, Ding;Tang, Zhouzhou;Xu, Qiang
花青素苷优先积累在特定种类柑橘的某些组织中。R2 R3-MYB转录因子（命名为Ruby 1）已被充分证明是柑橘花青素苷生物合成的激活剂。在这项研究中，我们的特点CsMYB 3，转录抑制剂，调节花青素的生物合成在柑橘。CsMYB 3在花色素组织中表达，其表达与花色素关键激活因子Ruby 1密切相关。在拟南芥中过量表达CsMYB 3导致氮胁迫下花青素的减少。在过量表达CsRuby 1的草莓和拟南芥中过量表达CsMYB 3降低了花色素苷的积累水平。瞬时启动子激活实验表明，CsMYB 3能抑制CsRuby 1/CsbHLH 1复合物对花青素生物合成基因的激活作用。此外，CsMYB 3可以转录激活CsRuby 1通过启动子结合，从而形成一个'激活-阻遏'环来调节柑橘花青素的生物合成。本研究表明，CsMYB 3在柑橘花色素苷生物合成调控中起着抑制剂的作用，并提出了由CsRuby 1和CsMYB 3构成的柑橘花色素苷生物合成调控的“激活-抑制”环模型。
Anthocyanins are preferentially accumulated in certain tissues of particular species of citrus. A R2R3-MYB transcription factor (named Ruby1) has been well documented as an activator of citrus anthocyanin biosynthesis. In this study, we characterized CsMYB3, a transcriptional repressor that regulates anthocyanin biosynthesis in citrus. CsMYB3 was expressed in anthocyanin-pigmented tissues, and the expression was closely associated with that of Ruby1, which is a key anthocyanin activator. Overexpression of CsMYB3 in Arabidopsis resulted in a decrease in anthocyanins under nitrogen stress. Overexpression of CsMYB3 in the background of CsRuby1-overexpressing strawberry and Arabidopsis reduced the anthocyanin accumulation level. Transient promoter activation assays revealed that CsMYB3 could repress the activation capacity of the complex formed by CsRuby1/CsbHLH1 for the anthocyanin biosynthetic genes. Moreover, CsMYB3 could be transcriptionally activated by CsRuby1 via promoter binding, thus forming an 'activator-and-repressor' loop to regulate anthocyanin biosynthesis in citrus. This study shows that CsMYB3 plays a repressor role in the regulation of anthocyanin biosynthesis and proposes an 'activator-and-repressor' loop model constituted by CsRuby1 and CsMYB3 in the regulation of anthocyanin biosynthesis in citrus.