Heterologous expression of OsWRKY6 gene in Arabidopsis activates the expression of defense related genes and enhances resistance to pathogens.

The WRKY proteins are a major family of plant transcription factors implicated in the regulation of plant defense mechanisms against pathogens. OsWRKY6 was isolated based on expression profiling data carried out with samples infected by Xanthomonas oryzae pv. oryzae (Xoo). OsWRKY6 encodes a DNA binding protein that contains one WRKY domain, a nuclear localization signal and C(2)H(2)-type zinc finger motif. OsWRKY6 is a member of the group II family of WRKY proteins. Based on the result of yeast one hybrid assay this OsWRKY6 protein binds to the typical W box ((T)TGACC/T). OsWRKY6 functions as a transcriptional activator in yeast. OsWRKY6 enhanced the expression of the reporter gene downstream of OsPR1 promoter, indicating that OsWRKY6 is a transcriptional activator in rice as well. Heterologous expression of OsWRKY6 enhanced disease resistance to pathogen. Defense-related genes were constitutively expressed in Arabidopsis transgenic lines overexpressing OsWRKY6. All together, OsWRKY6 functions as a positive transcriptional regulator of the plant defense response.