Abstract: WRKY is a superfamily of transcription factors unique to plants and was so named because all family members contain a conserved WRKYGQK domain. Seventy-four members have been identified from Arabidopsis thaliana. WRKY proteins regulate target gene expression by specifically binding to a TTGAC motif or W-box located in the promoter region of the target genes.Expression of the WRKY gene occurs transiently at an early stage of induction by pathogens, wounding, signal molecules or senescence. In addition to their defense response, WRKY proteins may also participate in regulating the expression of a wide range of genes involved in various biological processes such as trichome development, carbohydrate metabolism and fruit ripening.