Yang G, Zhang W, Liu Z, Yi-Maer A-Y, Zhai M, Xu Z
Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Yangling, Shaanxi, China.
Agronomy College, Heilongjiang Bayi Agricultural University, Daqing, China.
Plant Biol (Stuttg). 2017 Mar;19(2):268-278. doi: 10.1111/plb.12524. Epub 2016 Dec 7.
WRKY transcription factors belong to a large protein family that is involved in diverse developmental processes and abiotic stress responses. Currently, there is little understanding of the role of WRKY transcription factors in regulatory mechanisms in plants, especially in the protein-protein interactions that are essential for biological regulatory functions and networks. In the present study, yeast one-hybrid, yeast two-hybrid, transient expression and quantitative RT-PCR were applied to investigate the potential characteristics of two WRKY proteins from Juglans regia, JrWRKY2 (GenBank Accession No. KU057089) and JrWRKY7 (GenBank Accession No. KP784651). JrWRKY2 and JrWRKY7 can form homodimers and interact with each other. JrWRKY2 and JrWRKY7 can bind to W-box motifs. Similarly high levels of transcription were found for JrWRKY2 and JrWRKY7 under NaCl and polyethylene glycol (PEG) stresses, as well as at different developmental stages, e.g., the pistil or terminal leaf. JrWRKY2 and JrWRKY7 were transiently overexpressed in an independent manner in the terminal leaf. Analyses of superoxide dismutase (SOD) and peroxidase (POD) activities, proline and malondialdehyde (MDA) contents, and electrolyte leakage rate showed that JrWRKY2 and JrWRKY7 overexpression improved plant tolerance to NaCl, PEG, abscisic acid, and cold stress. Additionally, JrWRKY2 and JrWRKY7 overexpression elevated transcription of SOD, POD, glutathione peroxidase (GPX), catalase (CAT), ascorbate peroxidase (APX), and MYB genes, but downregulated the expression of NAC. Overall, the results demonstrate that JrWRKY2 and JrWRKY7 are dimeric proteins that can form functional homodimers and interact with each other and that they are involved in abiotic stress responses.
WRKY转录因子属于一个大型蛋白质家族，参与多种发育过程和非生物胁迫反应。目前，人们对WRKY转录因子在植物调控机制中的作用了解甚少，尤其是在对生物调控功能和网络至关重要的蛋白质-蛋白质相互作用方面。在本研究中，应用酵母单杂交、酵母双杂交、瞬时表达和定量RT-PCR来研究来自核桃（Juglans regia）的两种WRKY蛋白JrWRKY2（GenBank登录号KU057089）和JrWRKY7（GenBank登录号KP784651）的潜在特性。JrWRKY2和JrWRKY7可以形成同二聚体并相互作用。JrWRKY2和JrWRKY7可以与W-盒基序结合。在NaCl和聚乙二醇（PEG）胁迫下以及在不同发育阶段，例如雌蕊或顶叶中，发现JrWRKY2和JrWRKY7的转录水平同样较高。JrWRKY2和JrWRKY7在顶叶中以独立的方式瞬时过表达。对超氧化物歧化酶（SOD）和过氧化物酶（POD）活性、脯氨酸和丙二醛（MDA）含量以及电解质渗漏率的分析表明，JrWRKY2和JrWRKY7的过表达提高了植物对NaCl、PEG、脱落酸和冷胁迫的耐受性。此外，JrWRKY2和JrWRKY7的过表达提高了SOD、POD、谷胱甘肽过氧化物酶（GPX）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和MYB基因的转录，但下调了NAC的表达。总体而言，结果表明JrWRKY2和JrWRKY7是二聚体蛋白，它们可以形成功能性同二聚体并相互作用，并且它们参与非生物胁迫反应。
