The WUSCHEL-Related Homeobox Gene WOX11 Is Required to Activate Shoot-Borne Crown Root Development in Rice
The WUSCHEL-Related Homeobox Gene WOX11 Is Required to Activate Shoot-Borne Crown Root Development in Rice
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DOI：
10.1105/tpc.108.061655
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发表时间：
2009-03-01
期刊：
影响因子：
11.6
通讯作者：
Zhou, Dao-Xiu
中科院分区：
文献类型：
--
作者：
Zhao, Yu;Hu, Yongfeng;Zhou, Dao-Xiu
在水稻（Oryza sativa）中，茎生冠根是主要的根类型，并且作为正常植物发育的一部分在较低的茎节处发生。然而，冠根发育的调控机制知之甚少。在这项工作中，我们表明，WUSCHEL相关的同源盒（WOX）基因，WOX11，参与激活冠根的出现和生长。WOX11被发现在新兴的冠状根和根分生组织的细胞分裂区域中表达。外源生长素或细胞分裂素均可诱导表达。该基因的失功能突变或下调降低了冠根的数量和生长速率，而该基因的过表达诱导早熟冠根生长，并通过在上部茎节和小花基部产生冠根来显著增加根生物量。在WOX11过表达和RNA干扰转基因植株中，生长素和细胞分裂素应答基因的表达受到影响。进一步的分析表明，WOX11直接抑制RR2，一个A型细胞分裂素反应调节基因，被发现在冠根原基中表达。结果表明，WOX11可能是生长素和细胞分裂素信号的整合剂，在冠根发育过程中，该信号输入RR2以调节细胞增殖。
In rice (Oryza sativa), the shoot-borne crown roots are the major root type and are initiated at lower stem nodes as part of normal plant development. However, the regulatory mechanism of crown root development is poorly understood. In this work, we show that a WUSCHEL-related Homeobox (WOX) gene, WOX11, is involved in the activation of crown root emergence and growth. WOX11 was found to be expressed in emerging crown roots and later in cell division regions of the root meristem. The expression could be induced by exogenous auxin or cytokinin. Loss-of-function mutation or down-regulation of the gene reduced the number and the growth rate of crown roots, whereas overexpression of the gene induced precocious crown root growth and dramatically increased the root biomass by producing crown roots at the upper stem nodes and the base of florets. The expressions of auxin- and cytokinin-responsive genes were affected in WOX11 overexpression and RNA interference transgenic plants. Further analysis showed that WOX11 directly repressed RR2, a type-A cytokinin-responsive regulator gene that was found to be expressed in crown root primordia. The results suggest that WOX11 may be an integrator of auxin and cytokinin signaling that feeds into RR2 to regulate cell proliferation during crown root development.