The WRKY Transcription Factor WRKY71/EXB1 Controls Shoot Branching by Transcriptionally Regulating RAX Genes in Arabidopsis
The WRKY Transcription Factor WRKY71/EXB1 Controls Shoot Branching by Transcriptionally Regulating RAX Genes in Arabidopsis
复制标题
拟南芥中 WRKY 转录因子 WRKY71/EXB1 通过转录调节 RAX 基因来控制芽分枝
DOI：
10.1105/tpc.15.00829
复制
发表时间：
2015-11-01
期刊：
影响因子：
11.6
通讯作者：
Qin, Genji
中科院分区：
文献类型：
--
作者：
Guo, Dongshu;Zhang, Jinzhe;Qin, Genji
植物的茎分枝对于发育可塑性和作物产量至关重要。侧生分生组织的形成受到几个关键转录因子的调控，包括腋生分生组织调节因子1（RAX1）、RAX2和RAX3。然而，茎分枝的调控网络在很大程度上仍然未知。在此，我们报道了对过多分枝1（EXB1）的鉴定，它影响腋生分生组织（AM）的起始和芽的活性。在功能获得性突变体exb1 - D中过表达EXB1会导致严重的丛生和矮化表型，这是由于过度的AM起始和芽活性升高所致。EXB1编码WRKY转录因子WRKY71，该因子已被证明具有反式激活活性。通过嵌合抑制子沉默技术破坏WRKY71/EXB1会导致分枝减少，这表明EXB1在茎分枝的控制中起重要作用。我们证明EXB1通过正向调控RAX1、RAX2和RAX3的转录来控制AM的起始。RAX基因的破坏部分挽救了由EXB1过表达引起的分枝表型。我们进一步表明EXB1还在茎分枝的控制中调节生长素内稳态。我们的数据表明EXB1通过调节RAX基因的转录和生长素途径在茎分枝中起关键作用。
EXB1 plays pivotal roles in shoot branching by positively regulating the key branch genes RAX1, RAX2, and RAX3 and by affecting auxin pathways. Plant shoot branching is pivotal for developmental plasticity and crop yield. The formation of branch meristems is regulated by several key transcription factors including REGULATOR OF AXILLARY MERISTEMS1 (RAX1), RAX2, and RAX3. However, the regulatory network of shoot branching is still largely unknown. Here, we report the identification of EXCESSIVE BRANCHES1 (EXB1), which affects axillary meristem (AM) initiation and bud activity. Overexpression of EXB1 in the gain-of-function mutant exb1-D leads to severe bushy and dwarf phenotypes, which result from excessive AM initiation and elevated bud activities. EXB1 encodes the WRKY transcription factor WRKY71, which has demonstrated transactivation activities. Disruption of WRKY71/EXB1 by chimeric repressor silencing technology leads to fewer branches, indicating that EXB1 plays important roles in the control of shoot branching. We demonstrate that EXB1 controls AM initiation by positively regulating the transcription of RAX1, RAX2, and RAX3. Disruption of the RAX genes partially rescues the branching phenotype caused by EXB1 overexpression. We further show that EXB1 also regulates auxin homeostasis in control of shoot branching. Our data demonstrate that EXB1 plays pivotal roles in shoot branching by regulating both transcription of RAX genes and auxin pathways.