A WRKY gene from Tamarix hispida, ThWRKY4, mediates abiotic stress responses by modulating reactive oxygen species and expression of stress-responsive genes

• Published in: Plant molecular biology 2013-07, Vol.82 (4-5), p.303-320
• Main Authors: Zheng, Lei, Liu, Guifeng, Meng, Xiangnan, Liu, Yujia, Ji, Xiaoyu, Li, Yanbang, Nie, Xianguang, Wang, Yucheng
• Format: Article
• Language: English
• Subjects: Abscisic Acid - pharmacology; Arabidopsis; Biochemistry; Biomedical and Life Sciences; Drought; Droughts; Electrolyte leakage; Gene expression; Gene Expression Regulation, Plant - drug effects; Gene Expression Regulation, Plant - genetics; Hydrogen peroxide; Life Sciences; Plant biology; Plant Pathology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Sciences; Plants, Genetically Modified - drug effects; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Reactive Oxygen Species - metabolism; Salts; Sodium Chloride - pharmacology; Tamaricaceae - drug effects; Tamaricaceae - genetics; Tamaricaceae - metabolism; Tamarix; Transcription Factors - genetics; Transcription Factors - metabolism; Transgenic plants
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-013-0063-y

WRKY transcription factors are involved in various biological processes, such as development, metabolism and responses to stress. However, their exact roles in abiotic stress tolerance are largely unknown. Here, we demonstrated a working model for the function of a WRKY gene ( ThWRKY4 ) from Tamarix hispida in the stress response. ThWRKY4 is highly induced by abscisic acid (ABA), salt and drought in the early period of stress (stress for 3, 6, or 9 h), which can be regulated by ABF (ABRE binding factors) and Dof (DNA binding with one finger), and also can be crossregulated by other WRKYs and autoregulated as well. Overexpression of ThWRKY4 conferred tolerance to salt, oxidative and ABA treatment in transgenic plants. ThWRKY4 can improve the tolerance to salt and ABA treatment by improving activities of superoxide dismutase and peroxidase, decreasing levels of O 2 − and H 2 O 2 , reducing electrolyte leakage, keeping the loss of chlorophyll, and protecting cells from death. Microarray analyses showed that overexpression of ThWRKY4 in Arabidopsis leads to 165 and 100 genes significantly up- and downregulated, respectively. Promoter scanning analysis revealed that ThWRKY4 regulates the gene expression via binding to W-box motifs present in their promoter regions. This study shows that ThWRKY4 functions as a transcription factor to positively modulate abiotic stress tolerances, and is involved in modulating reactive oxygen species.