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Differential Induction of Tobacco MAP Kinases by the Defense Signals Nitric Oxide, Salicylic Acid, Ethylene, and Jasmonic Acid

March 2000 , Volume 13 , Number  3
Pages  347 - 351

Dhirendra Kumar and Daniel F. Klessig

Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway 08854-8020, U.S.A.

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Accepted 13 November 1999.

In tobacco, two mitogen-activated protein (MAP) kinases, designated salicylic acid (SA)-induced protein kinase (SIPK) and wounding-induced protein kinase (WIPK) are activated in a disease resistance-specific manner following pathogen infection or elicitor treatment. To investigate whether nitric oxide (NO), SA, ethylene, or jasmonic acid (JA) are involved in this phenomenon, the ability of these defense signals to activate these kinases was assessed. Both NO and SA activated SIPK; however, they did not activate WIPK. Additional analyses with transgenic NahG tobacco revealed that SA is required for the NO-mediated induction of SIPK. Neither JA nor ethylene activated SIPK or WIPK. Thus, SIPK may function downstream of SA in the NO signaling pathway for defense responses, while the signals responsible for resistance-associated WIPK activation have yet to be determined.

© 2000 The American Phytopathological Society