Functional characterization of the CKRC1/TAA1 gene and dissection of hormonal actions in the Arabidopsis root.
Functional characterization of the CKRC1/TAA1 gene and dissection of hormonal actions in the Arabidopsis root.
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DOI：
10.1111/j.1365-313x.2011.04509.x
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发表时间：
2011-05
期刊：
影响因子：
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通讯作者：
Zhao-Yang Zhou;Chun-Guang Zhang;Lei Wu;Cai-Guo Zhang;J. Chai;Ming Wang;A. Jha;P. Jia;
中科院分区：
文献类型：
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作者：
Zhao-Yang Zhou;Chun-Guang Zhang;Lei Wu;Cai-Guo Zhang;J. Chai;Ming Wang;A. Jha;P. Jia;
细胞分裂素(CK)影响植物生长发育的许多方面，其功能往往涉及与生长素、乙烯等其他植物激素的复杂相互作用。然而，CK的作用及其与其他生长调节剂相互作用的分子机制仍然知之甚少。在这里，我们描述了拟南芥CK诱导的卷根1(Ck Rc1)突变体的分离和特性。CKRC1编码一个参与吲哚-3-乙酸(IAA)生物合成的吲哚-3-丙酮酸(IPA)途径的色氨酸转氨酶(TAA1)。在初生根的生长过程中，ck rc1突变体表现出向根重力反应(GR)缺陷，对CK的抗性增强。这些缺陷可以通过外源生长素或IPA来修复。此外，我们发现CK以AHK3/ARR1/12依赖和不依赖乙烯的方式上调CKRC1/TAA1的表达，但抑制根中生长素的极性运输。我们的结果表明，CK不仅通过下调生长素的极地运输，而且还通过刺激局部生长素的生物合成来调控根的生长发育。
Cytokinin (CK) influences many aspects of plant growth and development, and its function often involves intricate interactions with other phytohormones such as auxin and ethylene. However, the molecular mechanisms underlying the role of CK and its interactions with other growth regulators are still poorly understood. Here we describe the isolation and characterization of the Arabidopsis CK-induced root curling 1 (ckrc1) mutant. CKRC1 encodes a previously identified tryptophan aminotransferase (TAA1) involved in the indole-3-pyruvic acid (IPA) pathway of indole-3-acetic acid (IAA) biosynthesis. The ckrc1 mutant exhibits a defective root gravitropic response (GR) and an increased resistance to CK in primary root growth. These defects can be rescued by exogenous auxin or IPA. Furthermore, we show that CK up-regulates CKRC1/TAA1 expression but inhibits polar auxin transport in roots in an AHK3/ARR1/12-dependent and ethylene-independent manner. Our results suggest that CK regulates root growth and development not only by down-regulating polar auxin transport, but also by stimulating local auxin biosynthesis.