Abstract
Mitogen-activated protein kinases (MAPKs) are components of signaling cascades that transduce extracellular stimuli into intracellular signaling. In plants, wounding causes activation of MAPKs and production of jasmonic acid (JA) and ethylene (ET). The tobacco MAPKs WIPK and SIPK are activated by wounding. Activation of WIPK and SIPK is required for wound-induced JA production, and activation of SIPK is required for ET production. To examine whether the regulation of production of JA and ET by WIPK and SIPK is a general mechanism for other plant species, we used mutants (mpk3 and mpk6) of their Arabidopsis orthologs and transgenic plants in which both MPK3 and MPK6 were silenced by RNAi (MPK3/MPK6RNAi). Wound-induced ET production was significantly reduced in mpk6 and MPK3/MPK6RNAi plants. The mpk3, mpk6, and MPK3/MPK6RNAi plants produced the same level of JA as did wild type, suggesting that the functions of MPK3 and MPK6 in the wound response of Arabidopsis are partially different from those of WIPK and SIPK in tobacco. We also report a metabolomics approach to examine how MPK3 and MPK6 regulate plant metabolism during the wound response.
