Abstract

Arabidopsis thaliana WRKY28, which is strongly induced by H₂O₂ stress, is one of the group II WRKY proteins and responds to Botrytis cinerea. In this study, we successfully generated up and down-regulating WRKY28 transgenic A. thaliana lines. Our investigationinto the action of WRKY28 demonstrated that the down-regulation of WRKY28 resulted in susceptible of plants. The enhanced susceptible in down-regulating plants was associated with the suppression of jasmonate (JA) and ethylene (ET) regulated PDF_1.2gene by the necrotrophic fungal pathogen B. cinerea. In contrast, disease resistance and the expressions of JA and ET regulated PDF_1.2 genes are slightly enhanced in WRKY28 over-expressing plants. Thus, pathogen-induced WRKY28 transcription factor plays a key role in JA and ET mediated defense responses to B. cinerea. These results provide a genetic evidence of WRKY28 in plant defense.

Key words: Transcription factor, Botrytis cinerea, necrotroph fungus.