Activation of a Mitogen-Activated Protein Kinase NtMPK4 Is Involved In Ozone Tolerance Mediated JA Signaling Pathway In Tobacco

Abstract

Plant mitogen-activated protein kinases (MAPKs) have been involved in a multitude of biotic and abiotic stress responses, hormone responses, and regulation of cell division. Some MAPK cascades are involved in wound/JA signaling pathway. One of them, Arabidopsis MPK4 (AtMPK4) is required for JA-responsive gene expression, and AtMPK4 is activated by various stress responses in Arabidopsis. However, in our knowledge, there is no evidence about function of this MAPK in other plant species. In this study, to assess whether the MPK4 is involved in wound/JA signaling pathway in other plant species, we isolated tobacco MPK4 gene (NtMPK4) and generated the NtMPK4-silenced tobacco plant by RNA interference (RNAi). Using the transgenic plant, we show that NtMPK4 has an important role in wound response as well as WIPK and SIPK, and also is involved in ozone response by regulating a JA signaling pathway.