Department of Molecular Biotechnology and Kumho Life Science Laboratory, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 500-757, South Korea.
Plant Cell Rep. 2015 Jan;34(1):71-81. doi: 10.1007/s00299-014-1688-2. Epub 2014 Sep 25.
The Arabidopsis AP2/ERF family transcription factor AtERF15 is nuclear-localized and positively regulates ABA and stress responses. Abscisic acid (ABA) is a major plant hormone that controls the expression of hundreds genes involved in various aspects of plant growth and development, such as seed development, germination, seedling growth and abiotic stress response. Several cis-elements mediating the ABA-regulated gene expression have been reported, and one of the regulatory elements is Coupling Element 1 (CE1). We previously isolated a group of AP2/ERF family proteins that bind CE1, but their functions are mostly unknown. In this study, we demonstrate that one of the CE1 binding factors (CEBFs), AtERF15, is involved in ABA response. To investigate the AtERF15 function, we generated its overexpression (OX) lines by expressing the AtERF15 coding region under the control of CaMV 35S promoter and analyzed their phenotypes. We found that the AtERF15 OX lines were hypersensitive to ABA at the germination stage. The ABA hypersensitivity was also observed in our root elongation assay of seedlings. Furthermore, the transgenic lines were hypersensitive to high salinity and high osmolarity at the seedling establishment stage, and the transgenic seedlings were drought-tolerant. We also determined the tissue-specific expression pattern and the subcellular localization of AtERF15. Our results indicate that it is highly expressed in roots and embryos and nuclear-localized. Collectively, our data suggest that AtERF15 is a positive regulator of ABA response.
拟南芥 AP2/ERF 家族转录因子 AtERF15 定位于细胞核，正向调控 ABA 和应激响应。脱落酸（ABA）是一种主要的植物激素，控制着涉及植物生长和发育各个方面的数百个基因的表达，如种子发育、萌发、幼苗生长和非生物胁迫响应。已经报道了几种介导 ABA 调控基因表达的顺式元件，其中一个调控元件是耦合元件 1（CE1）。我们之前分离了一组结合 CE1 的 AP2/ERF 家族蛋白，但它们的功能大多未知。在这项研究中，我们证明了 CE1 结合因子（CEBFs）之一 AtERF15 参与 ABA 反应。为了研究 AtERF15 的功能，我们通过在 CaMV 35S 启动子的控制下表达 AtERF15 编码区，生成了其过表达（OX）系，并分析了它们的表型。我们发现，AtERF15 OX 系在萌发阶段对 ABA 敏感。在幼苗伸长试验中也观察到 ABA 超敏反应。此外，在幼苗定植阶段，转基因系对高盐度和高渗透压敏感，而转基因幼苗耐旱。我们还确定了 AtERF15 的组织特异性表达模式和亚细胞定位。我们的结果表明，它在根和胚胎中高度表达，并定位于细胞核。总之，我们的数据表明 AtERF15 是 ABA 反应的正向调节剂。
