Type-B ARR transcription factors, ARR10 and ARR12, are implicated in cytokinin-mediated regulation of protoxylem differentiation in roots of Arabidopsis thaliana.
Type-B ARR transcription factors, ARR10 and ARR12, are implicated in cytokinin-mediated regulation of protoxylem differentiation in roots of Arabidopsis thaliana.
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DOI：
10.1093/pcp/pcl040
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发表时间：
2007
影响因子：
4.9
通讯作者：
Akihiro Yokoyama;T. Yamashino;Yuichiro Amano;Y. Tajima;A. Imamura;H. Sakakibara;T. Mizuno
中科院分区：
文献类型：
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作者：
Akihiro Yokoyama;T. Yamashino;Yuichiro Amano;Y. Tajima;A. Imamura;H. Sakakibara;T. Mizuno
在拟南芥的磷酸化介导的细胞分裂素信号转导中，B型真实反应调节因子（ARR）家族的某些成员参与了主要由细胞分裂素受体[真实组氨酸激酶（AHK）]传播的调节网络。澄清参与细胞分裂素反应现象的每个B型ARR转录因子仍处于非常早期的阶段。本研究通过构建arr 10/arr 12双突变体，分析了ARR 10和ARR 12两个B型ARR基因的冗余功能。所得到的突变体植物表现出更强的表型，特别是根中的细胞分裂素作用（例如根伸长的抑制，从根外植体形成绿色愈伤组织）比每个单一突变体，这表明ARR 10和ARR 12冗余地在根中的细胞分裂素信号传导中发挥重要作用。这一想法得到了双突变体植物根特异性微阵列分析结果的进一步支持。我们还发现ARR 10和ARR 12参与了AHK依赖的信号通路，负调控根维管组织中的原生木质部特化。当双突变体与arr 1等位基因组合时，所得到的arr 1/arr 10/arr 12三重突变体显示出非常差的生长表型，与植物中几乎缺乏细胞分裂素受体活性的木腿（wol）突变体非常相似。在这种三重突变体中，根维管组织的规格也受到严重影响，如在wol。综上所述，我们认为ARR 10和ARR 12，以及ARR 1，在响应于根中细胞分裂素的AHK依赖的磷酸化信号传导中冗余地发挥关键作用。
In the phosphorelay-mediated cytokinin signal transduction of Arabidopsis thaliana, certain members of the type-B authentic response regulator (ARR) family are implicated in the regulatory networks that are primarily propagated by the cytokinin-receptors [authentic histidine kinases (AHKs)]. Clarification of the involvement of each type-B ARR transcription factor in cytokinin-responsive phenomena is still at a very early stage. Here we analyzed the redundant function of two type-B ARR genes, ARR10 and ARR12, by constructing an arr10/arr12 double mutant. The resulting mutant plants showed stronger phenotypes with special reference to the cytokinin action in roots (e.g. inhibition of root elongation, green callus formation from root explants) than those for each single mutant, suggesting that ARR10 and ARR12 redundantly play an important role in the cytokinin signaling in roots. This idea was further supported by results from root-specific microarray analyses with the double mutant plant. We also showed that ARR10 and ARR12 are involved in the AHK-dependent signaling pathway that negatively regulates protoxylem specification in root vascular tissues. When the double mutant is combined with an arr1 allele, the resultant arr1/arr10/arr12 triple mutant showed phenotypes displaying a very poor growth, quite similar to those of the wooden leg (wol) mutant that virtually lacks cytokinin receptor activities in plants. In this triple arr mutant, the specification of root vascular tissues is also affected as severely as in wol. Taken together, we propose that ARR10 and ARR12, together with ARR1, redundantly play pivotal roles in the AHK-dependent phosphorelay signaling in response to cytokinin in roots.