Submergence confers immunity mediated by the WRKY22 transcription factor in Arabidopsis

We found that expression of genes that encode members of the WRKY transcription factor (TF) family was rapidly induced upon submergence in Arabidopsis, and this induction correlated with induction of a large portion of innate immunity marker genes. Further, prior submergence treatment conferred higher resistance to the bacterial pathogen Pseudomonas syringae in Arabidopsis. Among the WRKY genes tested, WRKY22 had the highest level of induction during the early stages of submergence. Compared to the wild-type, WRKY22¬ T-DNA insertion mutants wrky22-ko1 and wrky22-ko2 had lower disease resistance, and lower induction of innate immunity markers, such as FRK1 and WRKY53, after submergence. Furthermore, transcriptomic analyses of wrky22-ko2 and chromatin immunoprecipitation identified several potential targets of WRKY22, which included genes encoding a TIR domain containing protein, a plant peptide hormone and many OLIGO PEPTIDE TRANSPORTER (OPT) genes, all of which may lead to induction of innate immunity. In conclusion, we propose that submergence triggers innate immunity in Arabidopsis via WRKY22, a response that may protect against a higher probability of pathogen infection either during or after flood.
Ming-Che Shih

 

Co-researchers:Hsu, F-C., Chou, M.-Y., Chou, S.-J., Li, Y.-R., Peng, H.-P.,