School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China.
School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
Plant Cell. 2018 Nov;30(11):2761-2778. doi: 10.1105/tpc.18.00584. Epub 2018 Oct 17.
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 function by ethylene (and therefore auxin distribution) are poorly understood. Here, we report that the plant-specific and ethylene-responsive HD-Zip gene is involved in ethylene-mediated inhibition of primary root elongation in Biochemical and genetic analyses demonstrated that is ethylene responsive and acts downstream of (). 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 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 , (), and 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.
气态激素乙烯参与植物的许多生理过程。乙烯抑制根伸长涉及 PIN 形成蛋白 2 (PIN2)介导的向基生长素运输，但乙烯（因此生长素分布）调节功能的分子机制尚不清楚。在这里，我们报告植物特异性和乙烯响应的 HD-Zip 基因 参与乙烯介导的拟南芥主根伸长抑制。生化和遗传分析表明， 是乙烯响应的，并且作用于 （）的下游。 敲低突变体在主根伸长过程中表现出对乙烯不敏感的表型，而其过表达导致根短，如在乙烯处理的植物中观察到的。此外，根生长素分布和向重力性在 敲低和过表达系中受损。与这些发现一致，体外和体内结合实验表明 HB52 通过物理结合其启动子区域来调节生长素运输相关基因的表达，包括 、 ( ) 和 。这些发现表明 HB52 通过调节 EIN3 下游的生长素运输成分的表达来参与乙烯介导的根伸长抑制，揭示了 HB52 在植物生长和发育过程中乙烯和生长素信号转导的串扰中作为重要节点的机制。
