OsBWMK1 mediates SA-dependent defense responses by activating the transcription factor OsWRKY33.
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(2)O(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.
Koo
Sung Cheol
SC
Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea.
Moon
Byeong Cheol
BC
Kim
Jong Kyong
JK
Kim
Cha Young
CY
Sung
Sun Jin
SJ
Kim
Min Chul
MC
Cho
Moo Je
MJ
Cheong
Yong Hwa
YH
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011523:Protoplasts / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D016335:Zinc Fingers
D010940:Plant Proteins; D014157:Transcription Factors; D006861:Hydrogen Peroxide; C403286:MPK12 protein, Oryza sativa; D020928:Mitogen-Activated Protein Kinases; D020156:Salicylic Acid