Expression of the subgroup IIIf bHLH transcription factor CpbHLH1 from Chimonanthus praecox (L.) in transgenic model plants inhibits anthocyanin accumulation
Expression of the subgroup IIIf bHLH transcription factor CpbHLH1 from Chimonanthus praecox (L.) in transgenic model plants inhibits anthocyanin accumulation
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DOI：
10.1007/s00299-020-02537-9
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发表时间：
2020-04-24
影响因子：
6.2
通讯作者：
Zhao, Kaige
中科院分区：
文献类型：
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作者：
Zhao, Rong;Song, Xiaoxi;Zhao, Kaige
关键信息在拟南芥和烟草中过表达CpbHLH 1通过抑制类黄酮生物合成途径中晚期生物合成基因的表达导致花青素积累的急剧减少。许多基本螺旋-环-螺旋（bHLH）转录因子（TF）的亚组IIIf已被鉴定为花青素相关的激活剂在高等植物中，但有关bHLH TF抑制花青素积累的信息仍然很少。本研究以蜡梅（Chimonanthuspraecox（L.）被鉴定为花青素积累的负调节剂。我们的研究结果表明，CpbHLH 1在模式植物拟南芥和烟草中的过表达，导致花青素含量急剧下降，而原花青素的含量几乎没有受到影响。对类黄酮生物合成途径中结构基因的定量RT-PCR（qRT-PCR）分析表明，CpbHLH 1主要通过抑制晚期生物合成基因（LBG）的表达来抑制花青素苷的积累。通过酵母双杂交（Y2 H）和双分子荧光互补（BiFC）检测CpbHLH 1蛋白和AtPAP 1/NtAN 2蛋白之间的相互作用。这是第一个在双子叶植物中发现的花色素苷生物合成的bHLH阻遏物。这些结果可以帮助我们更好地了解植物中的花青素调控网络，并可能为bHLH蛋白的多种功能提供见解。
Key message Overexpression of CpbHLH1 in Arabidopsis and tobacco resulted in a dramatic decrease in anthocyanin accumulation by repressing the expression of late biosynthesis genes in the flavonoid biosynthesis pathway. Many basic helix-loop-helix (bHLH) transcription factors (TFs) of subgroup IIIf have been characterized as anthocyanin-associated activators in higher plants, but information regarding bHLH TFs that inhibit anthocyanin accumulation remains scarce. In this study, the subgroup IIIf bHLH TF CpbHLH1 from Chimonanthus praecox (L.) was identified as a negative regulator of anthocyanin accumulation. Our results showed that overexpression of CpbHLH1 in model plant species, Arabidopsis and tobacco, resulted in a dramatic decrease in anthocyanin content, whereas the content of proanthocyanidin was little affected. Quantitative RT-PCR (qRT-PCR) assays of the structural genes in the flavonoid biosynthesis pathway revealed that CpbHLH1 inhibits anthocyanin accumulation mainly through repressing the expression of late biosynthesis genes (LBGs). Interactions between CpbHLH1 protein and AtPAP1/NtAN2 protein were detected via yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. This is the first bHLH repressor of anthocyanin biosynthesis identified in dicotyledons. These results can help us better understand the anthocyanin regulatory network in plants and may provide insights into the diverse functions of bHLH proteins.