Arabidopsis BRANCHED1 acts as an integrator of branching signals within axillary buds
Arabidopsis BRANCHED1 acts as an integrator of branching signals within axillary buds
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DOI：
10.1105/tpc.106.048934
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发表时间：
2007-02-01
期刊：
影响因子：
11.6
通讯作者：
Cubas, Pilar
中科院分区：
文献类型：
--
作者：
Aguilar-Martinez, Jose Antonio;Poza-Carrion, Cesar;Cubas, Pilar
枝条的分枝模式取决于一个关键的发育决定：腋芽是长出形成枝条，还是在叶腋处休眠。这一决定是由激素信号调节的内源性和环境刺激控制的。虽然参与这一过程的长距离信号传递的基因已经被鉴定出来，但在拟南芥中，芽内响应导致生长停滞的基因仍然未知。在这里，我们描述了一个拟南芥基因，该基因编码一个与玉米(Zea Mays)teosinte分支1(Tb1)紧密相关的TCP转录因子BRANCHED1(Brc1)，它代表了控制分枝的信号在腋芽中整合的关键点。BRc1在发育中的芽中表达，在那里它阻止了芽的发育。BRC1下调调控会导致分支机构的扩张。BRC1对控制分枝的发育和环境刺激作出反应，并调节对这些刺激的反应。突变和表达分析表明，BRC1位于腋生生长途径的下游，是生长素诱导的顶端优势所必需的。因此，BRC1在芽中作为控制芽生长的信号的整合因子，并将它们转化为细胞生长停滞的反应。BRc1/tb1功能在远缘被子植物中的保守性表明，在开花植物辐射之前，分枝控制整合的单一祖先机制已经进化。
Shoot branching patterns depend on a key developmental decision: whether axillary buds grow out to give a branch or whether they remain dormant in the axils of leaves. This decision is controlled by endogenous and environmental stimuli mediated by hormonal signals. Although genes involved in the long-distance signaling of this process have been identified, the genes responding inside the buds to cause growth arrest remained unknown in Arabidopsis thaliana. Here, we describe an Arabidopsis gene encoding a TCP transcription factor closely related to teosinte branched1 (tb1) from maize (Zea mays), BRANCHED1 (BRC1), which represents a key point at which signals controlling branching are integrated within axillary buds. BRC1 is expressed in developing buds, where it arrests bud development. BRC1 downregulation leads to branch outgrowth. BRC1 responds to developmental and environmental stimuli controlling branching and mediates the response to these stimuli. Mutant and expression analyses suggest that BRC1 is downstream of the MORE AXILLARY GROWTH pathway and that it is required for auxin-induced apical dominance. Therefore, BRC1 acts inside the buds as an integrator of signals controlling bud outgrowth and translates them into a response of cell growth arrest. The conservation of BRC1/tb1 function among distantly related angiosperm species suggests that a single ancestral mechanism of branching control integration evolved before the radiation of flowering plants.