OsBWMK1 mediates SA-dependent defense responses by activating the transcription factor OsWRKY33

• Published in: Biochemical and biophysical research communications 2009-09, Vol.387 (2), p.365-370
• Main Authors: Koo, Sung Cheol, Moon, Byeong Cheol, Kim, Jong Kyong, Kim, Cha Young, Sung, Sun Jin, Kim, Min Chul, Cho, Moo Je, Cheong, Yong Hwa
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Arabidopsis; Arabidopsis - enzymology; Arabidopsis - genetics; Defense; Gene Expression Regulation, Plant; Hydrogen Peroxide - metabolism; MAP kinase; Mitogen-Activated Protein Kinases - genetics; Mitogen-Activated Protein Kinases - metabolism; Molecular Sequence Data; Oryza - enzymology; Oryza - genetics; Oryza sativa; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified; Promoter Regions, Genetic; Protoplasts - metabolism; Rice; Salicylic acid; Salicylic Acid - metabolism; Transcription Factors - metabolism; Transcriptional Activation; WRKY; Zinc Fingers
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2009.07.026

Mitogen-activated protein kinases (MAPKs) play important roles in responses to various environmental stresses. In a previous study, we demonstrated that OsBWMK1, which localizes in the nucleus, mediates PR gene expression by activating the OsEREBP1 transcription factor, and that the constitutive expression of OsBWMK1 also enhances resistance against pathogen infections [Y.H. Cheong, B.C. Moon, J.K. Kim, C.Y. Kim, M.C. Kim, I.H. Kim, C.Y. Park, J.C. Kim, B.O. Park, S.C. Koo, H.W. Yoon, W.S. Chung, C.O. Lim, S.Y. Lee, M.J. Cho, BWMK1, rice mitogen-activated protein kinase, locates in the nucleus and mediates pathogenesis-related gene expression by activation of a transcription factor, Plant Physiol. 132 (2003) 1961--1972]. Here, we report that OsBWMK1 phosphorylates OsWRKY33, which binds to the W-box element (TTGACCA) in several PR gene promoters, thereby enhancing DNA-binding activity of the factor to its in vitro cognate binding site. Transient coexpression of OsBWMK1 and OsWRKY33 in Arabidopsis protoplasts elevates SA-dependent expression of the GUS-reporter gene driven by the W-box element and the PR1 promoter. Furthermore, the levels of SA and H 2O 2 are elevated in 35S-OsBWMK1 transgenic plants that show HR-like cell death. Altogether, OsBWMK1 may mediate SA-dependent defense responses by activating the WRKY transcription factor in plants.