Department of Ornamental Horticulture, Sichuan Agricultural University, 211 Huimin Road, Wenjiang District, Chengdu, Sichuan 611130, PR China.
Plant Physiol Biochem. 2013 Aug;69:27-33. doi: 10.1016/j.plaphy.2013.04.016. Epub 2013 May 7.
WRKY transcription factor genes (TFs) play important roles in response to various abiotic stresses. However, the roles of the chrysanthemum WRKY genes in abiotic stress response remain obscure. In this study, we functionally characterized a novel WRKY gene, DgWRKY3, from chrysanthemum (Dendranthema grandiflorum). Its expression in the chrysanthemum was up-regulated by salinity or dehydration stress, but not by abscisic acid (ABA). The DgWRKY3-overexpression tobacco plants increase salt tolerance compared with wild-type (WT) tobacco plants. The increased levels of proline were observed in transgenic plants compared to WT plants under salt stress. In addition, the DgWRKY3 transgenic plants reduced accumulation of malondialdehyde (MDA) and hydrogen peroxide (H2O2) compared with WT plants, accompanied by higher activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and the greater accumulation of antioxidants including ascorbate (AsA) and glutathione (GSH) under salt stress. Moreover, the DgWRKY3 transgenic plants enhanced the expression of stress-related genes involved in osmotic adjustment and membrane protection (NtP5CS, NtLEA5, and NtERD10D) and oxidative stress response (NtSOD, NtPOD, NtCAT, and NtAPX) under salt stress. However, no significant difference in the expression of stress-related genes (NtP5CS, NtLEA5, NtERD10D, NtSOD, NtPOD, NtCAT, and NtAPX) was found between the DgWRKY3-overexpression and WT tobacco plants under normal conditions, despite the fact that the constitutive promoter was used to drive DgWRKY3. These findings suggest that DgWRKY3 functions as a positive regulator to mediate tolerance of plants to salt stress.
WRKY 转录因子基因（TFs）在应对各种非生物胁迫方面发挥着重要作用。然而，菊花 WRKY 基因在非生物胁迫响应中的作用仍不清楚。在这项研究中，我们从菊花（Dendranthema grandiflorum）中功能表征了一个新的 WRKY 基因 DgWRKY3。其表达在盐或干旱胁迫下上调，但不受脱落酸（ABA）的影响。与野生型（WT）烟草植物相比，DgWRKY3 过表达烟草植物提高了耐盐性。在盐胁迫下，转基因植物中的脯氨酸水平高于 WT 植物。此外，与 WT 植物相比，DgWRKY3 转基因植物减少了丙二醛（MDA）和过氧化氢（H2O2）的积累，同时抗氧化酶包括超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）的活性更高，在盐胁迫下抗氧化剂包括抗坏血酸（AsA）和谷胱甘肽（GSH）的积累更多。此外，DgWRKY3 转基因植物增强了与渗透调节和膜保护（NtP5CS、NtLEA5 和 NtERD10D）和氧化应激反应（NtSOD、NtPOD、NtCAT 和 NtAPX）相关的应激相关基因的表达，在盐胁迫下。然而，在正常条件下，DgWRKY3 过表达和 WT 烟草植物之间未发现应激相关基因（NtP5CS、NtLEA5、NtERD10D、NtSOD、NtPOD、NtCAT 和 NtAPX）的表达有显著差异，尽管使用组成型启动子来驱动 DgWRKY3。这些发现表明 DgWRKY3 作为一种正调控因子，介导植物对盐胁迫的耐受性。
