The Arabidopsis histidine phosphotransfer proteins are redundant positive regulators of cytokinin signaling
The Arabidopsis histidine phosphotransfer proteins are redundant positive regulators of cytokinin signaling
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DOI：
10.1105/tpc.106.045674
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发表时间：
2006-11-01
期刊：
影响因子：
11.6
通讯作者：
Kieber, Joseph J.
中科院分区：
文献类型：
--
作者：
Hutchison, Claire E.;Li, Jie;Kieber, Joseph J.
拟南芥组氨酸磷酸转移蛋白(AHPs)类似于细菌和酵母的组氨酸磷酸转移蛋白(HPTS)，它们在多步磷酸传递信号通路中发挥作用。细胞分裂素信号的当前模型是磷酸传递途径。为了评估AHP在细胞分裂素信号转导中的作用，我们分离了5个预测编码功能性HPTS的AHP基因中的T-DNA插入，并构建了多个插入突变体，其中包括一个ahp1，2，3，4，5五重突变体。在细胞分裂素反应分析中，单一的AHP突变体与野生型幼苗难以区分。然而，在不同的细胞分裂素检测中，各种较高顺序的突变体对细胞分裂素的敏感性降低，这表明AHP在细胞分裂素信号转导中起积极作用，并且AHP之间的功能重叠。与其他四种AHP相比，AHP4在某些细胞分裂素反应中可能起到负性作用。五重AHP突变体在生长发育方面表现出各种异常，包括育性降低、种子大小增加、维管发育减少和主根缩短。这些数据表明，大多数AHP是细胞分裂素信号的冗余、正调控因子，并影响植物发育的多个方面。
Arabidopsis thaliana histidine phosphotransfer proteins (AHPs) are similar to bacterial and yeast histidine phosphotransfer proteins (HPts), which act in multistep phosphorelay signaling pathways. A phosphorelay pathway is the current model for cytokinin signaling. To assess the role of AHPs in cytokinin signaling, we isolated T-DNA insertions in the five AHP genes that are predicted to encode functional HPts and constructed multiple insertion mutants, including an ahp1,2,3,4,5 quintuple mutant. Single ahp mutants were indistinguishable from wild-type seedlings in cytokinin response assays. However, various higher-order mutants displayed reduced sensitivity to cytokinin in diverse cytokinin assays, indicating both a positive role for AHPs in cytokinin signaling and functional overlap among the AHPs. In contrast with the other four AHPs, AHP4 may play a negative role in some cytokinin responses. The quintuple ahp mutant showed various abnormalities in growth and development, including reduced fertility, increased seed size, reduced vascular development, and a shortened primary root. These data indicate that most of the AHPs are redundant, positive regulators of cytokinin signaling and affect multiple aspects of plant development.