Pattern of Auxin and Cytokinin Responses for Shoot Meristem Induction Results from the Regulation of Cytokinin Biosynthesis by AUXIN RESPONSE FACTOR3
Pattern of Auxin and Cytokinin Responses for Shoot Meristem Induction Results from the Regulation of Cytokinin Biosynthesis by AUXIN RESPONSE FACTOR3
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生长素响应因子 3 调节细胞分裂素生物合成对芽分生组织诱导的生长素和细胞分裂素反应模式
DOI：
10.1104/pp.112.203166
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发表时间：
2013-01-01
期刊：
影响因子：
7.4
通讯作者：
Zhang, Xian Sheng
中科院分区：
文献类型：
--
作者：
Cheng, Zhi Juan;Wang, Liang;Zhang, Xian Sheng
新生器官再生是研究干细胞启动、细胞命运决定和激素信号转导等基本问题的极佳生物系统。尽管普遍认为生长素和细胞分裂素的反应相互作用来调节新生器官的再生，但这种串扰背后的分子机制却鲜为人知。在这里，我们证明了时空生物合成和极地运输导致了生长素在拟南芥中的局部分布，而这反过来又决定了细胞分裂素在新梢再生过程中的反应。生长素分布的遗传和药物干预扰乱了细胞分裂素的反应和ATP/ADP异戊烯基转移酶5(AtIPT5)的表达，影响干细胞的启动和分生组织的形成。转录数据表明，生长素反应因子3(ARF3)在新生器官再生过程中介导了生长素反应。事实上，ARF3的突变通过AtIPT5的错误表达导致细胞分裂素的异位生物合成，从而扰乱了器官再生。我们进一步表明，ARF3直接与AtIPT5的启动子结合，负调控AtIPT5的表达。因此，这项研究的结果揭示了生长素-细胞分裂素的串扰机制，涉及从头开始干细胞启动所需的不同的中间信号成分，并为植物器官发生的机制提供了新的线索。
De novo organ regeneration is an excellent biological system for the study of fundamental questions regarding stem cell initiation, cell fate determination, and hormone signaling. Despite the general belief that auxin and cytokinin responses interact to regulate de novo organ regeneration, the molecular mechanisms underlying such a cross talk are little understood. Here, we show that spatiotemporal biosynthesis and polar transport resulted in local auxin distribution in Arabidopsis (Arabidopsis thaliana), which in turn determined the cytokinin response during de novo shoot regeneration. Genetic and pharmacological interference of auxin distribution disrupted the cytokinin response and ATP/ADP ISOPENTENYLTRANSFERASE5 (AtIPT5) expression, affecting stem cell initiation and meristem formation. Transcriptomic data suggested that AUXIN RESPONSE FACTOR3 (ARF3) mediated the auxin response during de novo organ regeneration. Indeed, mutations in ARF3 caused ectopic cytokinin biosynthesis via the misexpression of AtIPT5, and this disrupted organ regeneration. We further showed that ARF3 directly bound to the promoter of AtIPT5 and negatively regulated AtIPT5 expression. The results from this study thus revealed an auxin-cytokinin cross talk mechanism involving distinct intermediate signaling components required for de novo stem cell initiation and shed new light on the mechanisms of organogenesis in planta.