HOMEOBOX PROTEIN52 Mediates the Crosstalk between Ethylene and Auxin Signaling during Primary Root Elongation by Modulating Auxin Transport-Related Gene Expression
HOMEOBOX PROTEIN52 Mediates the Crosstalk between Ethylene and Auxin Signaling during Primary Root Elongation by Modulating Auxin Transport-Related Gene Expression
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拟南芥 HB52 在初生根伸长过程中通过转录调节 PIN2、WAG1 和 WAG2 介导乙烯和生长素之间的串扰。
DOI：
10.1105/tpc.18.00584
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发表时间：
2018-11-01
期刊：
影响因子：
11.6
通讯作者：
Xiang, Cheng-Bin
中科院分区：
文献类型：
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作者：
Miao, Zi-Qing;Zhao, Ping-Xia;Xiang, Cheng-Bin
气态激素乙烯参与植物的许多生理过程。乙烯抑制的根伸长涉及 PIN-FORMED2 (PIN2) 介导的基瓣生长素转运，但乙烯调节 PIN2 功能（以及生长素分布）的分子机制尚不清楚。在这里，我们报道植物特异性和乙烯响应的 HD-Zip 基因 HB52 参与乙烯介导的拟南芥初生根伸长抑制。生化和遗传分析表明，HB52 具有乙烯反应性，并在 ETHYLENE-INSENSITIVE3 (EIN3) 下游发挥作用。 HB52 敲除突变体在初生根伸长过程中表现出对乙烯不敏感的表型，而其过度表达会导致短根，如在乙烯处理的植物中观察到的那样。此外，在 HB52 敲低和过表达品系中，根部生长素分布和向地性受到损害。与这些发现一致，体外和体内结合实验表明，HB52 通过物理结合到生长素转运相关基因的启动子区域来调节生长素转运相关基因的表达，包括 PIN2、WAVY ROOT GROWTH1 (WAG1) 和 WAG2。这些发现表明，HB52通过调节EIN3下游生长素转运成分的表达，在乙烯介导的根伸长抑制中发挥作用，揭示了HB52在植物生长和发育过程中乙烯和生长素信号传导之间串扰的重要节点的机制。
The gaseous hormone ethylene participates in many physiological processes in plants. Ethylene-inhibited root elongation involves PIN-FORMED2 (PIN2)-mediated basipetal auxin transport, but the molecular mechanisms underlying the regulation of PIN2 function by ethylene (and therefore auxin distribution) are poorly understood. Here, we report that the plant-specific and ethylene-responsive HD-Zip gene HB52 is involved in ethylene-mediated inhibition of primary root elongation in Arabidopsis thaliana. Biochemical and genetic analyses demonstrated that HB52 is ethylene responsive and acts downstream of ETHYLENE-INSENSITIVE3 (EIN3). HB52 knockdown mutants displayed an ethylene-insensitive phenotype during primary root elongation, while its overexpression resulted in short roots, as observed in ethylene-treated plants. In addition, root auxin distribution and gravitropism were impaired in HB52 knockdown and overexpression lines. Consistent with these findings, in vitro and in vivo binding experiments showed that HB52 regulates the expression of auxin transport-related genes, including PIN2, WAVY ROOT GROWTH1 (WAG1), and WAG2 by physically binding to their promoter regions. These findings suggest that HB52 functions in the ethylene-mediated inhibition of root elongation by modulating the expression of auxin transport components downstream of EIN3, revealing a mechanism in which HB52 acts as an important node in the crosstalk between ethylene and auxin signaling during plant growth and development.