A repressor motif-containing poplar R3 MYB-like transcription factor regulates epidermal cell fate determination and anthocyanin biosynthesis in Arabidopsis
A repressor motif-containing poplar R3 MYB-like transcription factor regulates epidermal cell fate determination and anthocyanin biosynthesis in Arabidopsis
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含有阻遏基序的杨树 R3 MYB 样转录因子调节拟南芥表皮细胞命运决定和花青素生物合成
DOI：
10.1007/s12374-015-0575-x
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发表时间：
2016-10-01
影响因子：
2.9
通讯作者：
Wang, Shucai
中科院分区：
文献类型：
--
作者：
Hu, Qingnan;Yang, Li;Wang, Shucai
单重复 R3 MYB 转录因子 (R3 MYB) 通过侧抑制机制调节拟南芥中表皮细胞的命运决定。之前我们已经证明杨树 R3 MYB 基因在拟南芥中表达时可调节毛状体的形成。在这里，我们报告了杨树 R3 MYB 样蛋白——毛果杨 R3 MYB-LIKE1 (PtrRML1) 的鉴定和功能表征。迄今为止，所有已鉴定的 MYB 转录因子都具有由 MYB 重复序列组成的高度保守的 N 端 DNA 结合结构域和高度可变的 C 端结构域。然而，PtrRML1 在其 C 端有一个 R3 MYB 重复序列，在 N 端有一个含有 LxLxL 阻遏基序的序列，其氨基酸数量约为已知 R3 MYB 的两倍。 PtrRML1 位于表达 PtrRML1-GFP 的转基因拟南芥植物的核中。 PtrRML1 抑制原生质体中的报告基因表达，并与植物细胞中的 GL3 相互作用。 PtrRML1 在拟南芥中的表达导致无毛表型、根毛数量增加和花青素积累减少。与这些观察结果一致，转基因植物中一些MBW组成基因及其一些参与表皮细胞命运决定和花青素生物合成调节的靶基因，包括TRY、CPC、ETC1、GL1、GL2、DFR、UF3GT和TT8的表达水平降低。
Single-repeat R3 MYB transcription factors (R3 MYBs) regulate epidermal cell fate determination in Arabidopsis through a lateral inhibition mechanism. Previously we have shown that poplar R3 MYB genes regulate trichome formation when expressed in Arabidopsis. Here we report the identification and functional characterization of a poplar R3 MYB-like protein,Populus trichocarpaR3 MYB-LIKE1 (PtrRML1). So far all the MYB transcription factors identified have a highly conserved N-terminal DNA-binding domain composed of MYB repeats and a highly variable C-terminal domain. However, PtrRML1 has a single R3 MYB repeat at its C-terminal and an LxLxL repressor motif-containing N-terminal, and with amino acids about twice of that of the known R3 MYBs. PtrRML1 is localized in nuclear in transgenic Arabidopsis plants expressingPtrRML1-GFP. PtrRML1 repressed reporter gene expression in protoplasts, and it interacted with GL3 in plant cells. Expression ofPtrRML1in Arabidopsis resulted in glabrous phenotypes, increased number of root hairs, and decreased anthocyanin accumulation. Consist with these observation, the expression levels of some MBW component genes and some of their target genes involved in the regulation of epidermal cell fate determination and anthocyanin biosynthesis, includingTRY,CPC,ETC1,GL1,GL2,DFR,UF3GTandTT8were reduced in the transgenic plants.