A functional homologue of Arabidopsis TTG1 from Freesia interacts with bHLH proteins to regulate anthocyanin and proanthocyanidin biosynthesis in both Freesia hybrida and Arabidopsis thaliana
A functional homologue of Arabidopsis TTG1 from Freesia interacts with bHLH proteins to regulate anthocyanin and proanthocyanidin biosynthesis in both Freesia hybrida and Arabidopsis thaliana
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小苍兰拟南芥 TTG1 的功能同源物与 bHLH 蛋白相互作用，调节小苍兰和拟南芥中花青素和原花青素的生物合成
DOI：
10.1016/j.plaphy.2019.05.015
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发表时间：
2019
影响因子：
6.5
通讯作者：
Wang Li
中科院分区：
文献类型：
--
作者：
Shan Xiaotong;Li Yueqing;Yang Song;Gao Ruifang;Zhou Liudi;Bao Tingting;Han Taotao;Wang Shucai;Gao Xiang;Wang Li
The MBW complex, consisting of MYB, basic helix-loop-helix (bHLH) and WD40 proteins, regulates multiple traits in plants, such as anthocyanin and proanthocyanidin biosynthesis and cell fate determination. The complex has been widely identified in dicot plants, whereas few studies are concentrated on monocot plants which are of crucial importance to decipher its functional diversities among angiosperms during evolution. In present study, a WD40 gene fromFreesia hybrida, designated asFhTTG1, was cloned and functionally characterized. Real-time PCR analysis indicated that it was expressed synchronously with the accumulation of both proanthocyanidins and anthocyanins inFreesiaflowers. Transient protoplast transfection and biomolecular fluorescence complementation (BiFC) assays demonstrated that FhTTG1 could interact with FhbHLH proteins (FhTT8L and FhGL3L) to constitute the MBW complex. Moreover, the transportation of FhTTG1 to nucleus was found to rely on FhbHLH factors. Outstandingly, FhTTG1 could highly activate the anthocyanin or proanthocyanidin biosynthesis related gene promoters when co-transfected with MYB and bHLH partners, implying that FhTTG1 functioned as a member of MBW complex to control the anthocyanin or proanthocyanidin biosynthesis inFreesia hybrida. Further ectopic expression assays inArabidopsis ttg1-1showed the defective phenotypes ofttg1-1were partially restored. Molecular biological assays validated FhTTG1 might interact with the endogenous bHLH factors to up-regulate genes responsible for anthocyanin and proanthocyanidin biosynthesis and trichome formation, indicating that FhTTG1 might perform exchangeable roles with AtTTG1. These results will not only contribute to the characterization of FhTTG1 inFreesiabut also shed light on the establishment of flavonoid regulatory system in monocot plants, especially inFreesia hybrida.
