Abstract
The involvement of the mitogen-activated protein kinase (MAPK) cascade in induced defense reactions of plants has been proposed. In a previous study, we reported that MAPK-like activity was activated in fungal elicitor-treated potato tubers. To gain a better understanding about the involvement of the MAPK cascade in defense reactions of potato, we cloned StMEK1, a potato ortholog of tobacco NtMEK2. StMEK1 shares more than 86% amino acid sequence identity with NtMEK2 and harbors conserved Ser/Thr in the activation loop. Agrobacterium-mediated expression of StMEK1 DD, a constitutively active mutant of StMEK1, induced hypersensitive response (HR)-like cell death in Nicotiana benthamiana leaf, preceded by the activation of SIPK and WIPK. In addition, transient expression of StMEK1 DD induced the transcript accumulation of defense genes such as PAL, TEAS, and EIG-I24 but decreased that of EIG-I30. These results suggest that StMEK1 is involved in both activation and repression of defense gene expression.
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Received: September 27, 2002 / Accepted: December 6, 2002
Acknowledgments The authors thank Dr. Jonathan D.G. Jones at the Sainsbury Laboratory for providing pSLJ4K1, Dr. Phil Mullineaux and Dr. Roger Hellens in John Innes Centre for the pGreen binary vector, Dr. Yuko Ohashi in at the National Institute of Agrobiological Resources for SIPK- and WIPK-specific antibodies, Dr. Joseph Chappell for tobacco sesquiterpene cyclase cDNA, and the Leaf Tobacco Research Center, Japan Tobacco Inc. for N. benthamiana seeds. We also thank Dr. Takashi Tsuge and Dr. Daigo Takemoto for helpful discussions, and the members of the Radioisotope a Research Center, Nagoya University, for technical assistance. This work was supported in part by a Research Fellowship from the Japan Society for the Promotion of Science for Young Scientists; by a Grant-in-Aid for Scientific Research (S) (14104004) from the Ministry of Education, Science, and Culture of Japan; and by a Grant-in-Aid for the “Research for the Future” program from the Japan Society for the Promotion of Science.
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Katou, S., Yamamoto, A., Yoshioka, H. et al. Functional analysis of potato mitogen-activated protein kinase kinase, StMEK1. J Gen Plant Pathol 69, 161–168 (2003). https://doi.org/10.1007/s10327-002-0030-y
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DOI: https://doi.org/10.1007/s10327-002-0030-y