Type B response regulators of Arabidopsis play key roles in cytokinin signaling and plant development
Type B response regulators of Arabidopsis play key roles in cytokinin signaling and plant development
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DOI：
10.1105/tpc.108.059584
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发表时间：
2008-08-01
期刊：
影响因子：
11.6
通讯作者：
Schaller, G. Eric
中科院分区：
文献类型：
--
作者：
Argyros, Rebecca D.;Mathews, Dennis E.;Schaller, G. Eric
拟南芥B型应答调节子（ARRs）是拟南芥中一类转录因子，在细胞分裂素信号转导途径中起正向调节作用。我们采用了一种基于突变体的方法来详细描述ARR 1，ARR 10和ARR 12在植物生长和发育中的作用。最明显的表型被发现在arr 1 -3 arr 10 -5 arr 12 -1三重功能丧失突变体，这表明几乎完全不敏感的高水平的外源应用细胞分裂素。三重突变体表现出降低的身材，由于减少细胞分裂的拍摄，增强种子大小，增加对光的敏感性，改变叶绿素和花青素的浓度，和一个流产的初生根与原生木质部，但没有后生木质部。微阵列分析显示，大多数细胞分裂素调控基因的表达需要ARR 1，ARR 10和ARR 12的功能。双突变体的表征揭示了B型ARR对突变体表型的不同贡献。我们的研究结果支持一个模型，其中细胞分裂素调节广泛的下游反应，通过行动的多步磷酸化，最终在转录调控ARR 1，ARR 10，和ARR 12。
The type B Arabidopsis Response Regulators (ARRs) of Arabidopsis thaliana are transcription factors that act as positive regulators in the two-component cytokinin signaling pathway. We employed a mutant-based approach to perform a detailed characterization of the roles of ARR1, ARR10, and ARR12 in plant growth and development. The most pronounced phenotype was found in the arr1-3 arr10-5 arr12-1 triple loss-of-function mutant, which showed almost complete insensitivity to high levels of exogenously applied cytokinins. The triple mutant exhibited reduced stature due to decreased cell division in the shoot, enhanced seed size, increased sensitivity to light, altered chlorophyll and anthocyanin concentrations, and an aborted primary root with protoxylem but no metaxylem. Microarray analysis revealed that expression of the majority of cytokinin-regulated genes requires the function of ARR1, ARR10, and ARR12. Characterization of double mutants revealed differing contributions of the type B ARRs to mutant phenotypes. Our results support a model in which cytokinin regulates a wide array of downstream responses through the action of a multistep phosphorelay that culminates in transcriptional regulation by ARR1, ARR10, and ARR12.