TDIF Peptide Signaling Regulates Vascular Stem Cell Proliferation via the WOX4 Homeobox Gene in Arabidopsis
TDIF Peptide Signaling Regulates Vascular Stem Cell Proliferation via the WOX4 Homeobox Gene in Arabidopsis
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DOI：
10.1105/tpc.110.076083
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发表时间：
2010-08-01
期刊：
影响因子：
11.6
通讯作者：
Fukuda, Hiroo
中科院分区：
文献类型：
--
作者：
Hirakawa, Yuki;Kondo, Yuki;Fukuda, Hiroo
植物生长和发育的不确定性取决于分生组织中发现的干细胞系统。拟南芥维管分生组织包括原形成层和形成层。在这些组织中，由 TDIF（气管元件分化抑制因子）肽和 TDR/PXY（TDIF 受体/与木质部插入的韧皮部）膜蛋白激酶组成的配体-受体对介导的细胞-细胞信号传导，促进原形成层细胞的增殖并抑制其木质部分化。在此，我们报道 WUSCHEL 相关的 HOMEOBOX 基因 WOX4 是 TDIF 信号通路的关键靶标。 WOX4优先在原形成层和形成层中表达，并且其表达水平在应用TDIF后以TDR依赖性方式上调。遗传分析表明，WOX4 是促进原形成层/形成层干细胞增殖所必需的，但并不抑制它们响应 TDIF 信号而进行木质部分化。因此，在 TDR 识别 TDIF 后，至少有两条细胞内信号通路分叉，可能独立调节血管干细胞的行为。对功能丧失突变体的详细观察表明，TDIF-TDR-WOX4 信号传导在维持次生生长期间维管分生组织组织中发挥着至关重要的作用。
The indeterminate nature of plant growth and development depends on the stem cell system found in meristems. The Arabidopsis thaliana vascular meristem includes procambium and cambium. In these tissues, cell-cell signaling, mediated by a ligand-receptor pair made of the TDIF (for tracheary element differentiation inhibitory factor) peptide and the TDR/PXY (for TDIF RECEPTOR/ PHLOEM INTERCALATED WITH XYLEM) membrane protein kinase, promotes proliferation of procambial cells and suppresses their xylem differentiation. Here, we report that a WUSCHEL-related HOMEOBOX gene, WOX4, is a key target of the TDIF signaling pathway. WOX4 is expressed preferentially in the procambium and cambium, and its expression level was upregulated upon application of TDIF in a TDR-dependent manner. Genetic analyses showed that WOX4 is required for promoting the proliferation of procambial/cambial stem cells but not for repressing their commitment to xylem differentiation in response to the TDIF signal. Thus, at least two intracellular signaling pathways that diverge after TDIF recognition by TDR might regulate independently the behavior of vascular stem cells. Detailed observations in loss-of-function mutants revealed that TDIF-TDR-WOX4 signaling plays a crucial role in the maintenance of the vascular meristem organization during secondary growth.