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ABSTRACT: 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.
Biochemical and Biophysical Research Communications 08/2009; 387(2):365-70. · 2.48 Impact Factor
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Yong Hwa Cheong,
Byeong Cheol Moon, Jong Kyong Kim,
Cha Young Kim,
Min Chul Kim,
Ihn Hyoung Kim,
Chan Young Park,
Jong Cheol Kim,
Byung Ouk Park,
Seong Cheol Koo,
Hae Won Yoon,
Woo Sik Chung,
Chae Oh Lim,
Sang Yeol Lee,
Moo Je Cho
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ABSTRACT: Mitogen-activated protein kinase (MAPK) cascades are known to transduce plant defense signals, but the downstream components of the MAPK have as yet not been elucidated. Here, we report an MAPK from rice (Oryza sativa), BWMK1, and a transcription factor, OsEREBP1, phosphorylated by the kinase. The MAPK carries a TDY phosphorylation motif instead of the more common TEY motif in its kinase domain and has an unusually extended C-terminal domain that is essential to its kinase activity and translocation to the nucleus. The MAPK phosphorylates OsEREBP1 that binds to the GCC box element (AGCCGCC) of the several basic pathogenesis-related gene promoters, which in turn enhances DNA-binding activity of the factor to the cis element in vitro. Transient co-expression of the BWMK1 and OsEREBP1 in Arabidopsis protoplasts elevates the expression of the beta-glucuronidase reporter gene driven by the GCC box element. Furthermore, transgenic tobacco (Nicotiana tabacum) plants overexpressing BWMK1 expressed many pathogenesis-related genes at higher levels than wild-type plants with an enhanced resistance to pathogens. These findings suggest that MAPKs contribute to plant defense signal transduction by phosphorylating one or more transcription factors.
Plant physiology 09/2003; 132(4):1961-72. · 6.53 Impact Factor
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Min Chul Kim,
Sang Hyoung Lee, Jong Kyong Kim,
Hyun Jin Chun,
Man Soo Choi,
Woo Sik Chung,
Byeong Cheol Moon,
Chang Ho Kang,
Chan Young Park,
Jae Hyuk Yoo,
Yun Hwan Kang,
Seong Cheol Koo,
Yoon Duck Koo,
Jae Cheol Jung,
Sun Tae Kim,
Paul Schulze-Lefert,
Sang Yeol Lee,
Moo Je Cho
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ABSTRACT: Transient influx of Ca(2+) constitutes an early event in the signaling cascades that trigger plant defense responses. However, the downstream components of defense-associated Ca(2+) signaling are largely unknown. Because Ca(2+) signals are mediated by Ca(2+)-binding proteins, including calmodulin (CaM), identification and characterization of CaM-binding proteins elicited by pathogens should provide insights into the mechanism by which Ca(2+) regulates defense responses. In this study, we isolated a gene encoding rice Mlo (Oryza sativa Mlo; OsMlo) using a protein-protein interaction-based screening of a cDNA expression library constructed from pathogen-elicited rice suspension cells. OsMlo has a molecular mass of 62 kDa and shares 65% sequence identity and scaffold topology with barley Mlo, a heptahelical transmembrane protein known to function as a negative regulator of broad spectrum disease resistance and leaf cell death. By using gel overlay assays, we showed that OsMlo produced in Escherichia coli binds to soybean CaM isoform-1 (SCaM-1) in a Ca(2+)-dependent manner. We located a 20-amino acid CaM-binding domain (CaMBD) in the OsMlo C-terminal cytoplasmic tail that is necessary and sufficient for Ca(2+)-dependent CaM complex formation. Specific binding of the conserved CaMBD to CaM was corroborated by site-directed mutagenesis, a gel mobility shift assay, and a competition assay with a Ca(2+)/CaM-dependent enzyme. Expression of OsMlo was strongly induced by a fungal pathogen and by plant defense signaling molecules. We propose that binding of Ca(2+)-loaded CaM to the C-terminal tail may be a common feature of Mlo proteins.
Journal of Biological Chemistry 06/2002; 277(22):19304-14. · 4.77 Impact Factor
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Min Chul Kim,
Sang Hyoung Lee, Jong Kyong Kim,
Hyun Jin Chun,
Man Soo Choi,
Woo Sik Chung,
Byeong Cheol Moon,
Chang Ho Kang,
Chan Young Park,
Jae Hyuk Yoo,
Yun Hwan Kang,
Seong Cheol Koo,
Yoon Duck Koo,
Jae Cheol Jung,
Sun Tae Kim,
Paul Schulze-Lefert,
Sang Yeol Lee,
Moo Je Cho
[show abstract]
[hide abstract]
ABSTRACT: Transient influx of Ca2+ constitutes an early event in the signaling cascades that trigger plant defense responses. However, the downstream components
of defense-associated Ca2+ signaling are largely unknown. Because Ca2+ signals are mediated by Ca2+-binding proteins, including calmodulin (CaM), identification and characterization of CaM-binding proteins elicited by pathogens
should provide insights into the mechanism by which Ca2+ regulates defense responses. In this study, we isolated a gene encoding rice Mlo (Oryza sativa Mlo;OsMlo) using a protein-protein interaction-based screening of a cDNA expression library constructed from pathogen-elicited rice
suspension cells. OsMlo has a molecular mass of 62 kDa and shares 65% sequence identity and scaffold topology with barley
Mlo, a heptahelical transmembrane protein known to function as a negative regulator of broad spectrum disease resistance and
leaf cell death. By using gel overlay assays, we showed that OsMlo produced inEscherichia coli binds to soybean CaM isoform-1 (SCaM-1) in a Ca2+-dependent manner. We located a 20-amino acid CaM-binding domain (CaMBD) in the OsMlo C-terminal cytoplasmic tail that is
necessary and sufficient for Ca2+-dependent CaM complex formation. Specific binding of the conserved CaMBD to CaM was corroborated by site-directed mutagenesis,
a gel mobility shift assay, and a competition assay with a Ca2+/CaM-dependent enzyme. Expression ofOsMlo was strongly induced by a fungal pathogen and by plant defense signaling molecules. We propose that binding of Ca2+-loaded CaM to the C-terminal tail may be a common feature of Mlo proteins.
Journal of Biological Chemistry 05/2002; 277(22):19304-19314. · 4.77 Impact Factor
