The 30th International Conference on Arabidopsis Research (ICAR 2019)

526 / 2019-03-04 21:51:39

MPK4 phosphorylation dynamics and interactome in plant immunity

AtMPK4, phosphorylation, interactome, plant immunity, pathogen

Plenary track > Biotic Stress

Arabidopsis MAP kinase 4 (AtMPK4) was found to be a negative player in plant immunity, and it could be activated by pathogen-associated molecular patterns (PAMPs), such as flg22. How MPK4 is activated and regulates plant defense remain elusive. In this study, we report Arabidopsis defense against a bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000 when a MPK4 is overexpressed. We showed an increase in pathogen resistance and suppression of jasmonic acid (JA) signaling in the overexpressing (OE) plants. We also showed that the OE plants have increased sensitivity to flg22-triggered reactive oxygen species (ROS) burst in guard cells, which resulted in enhanced stomatal closure compared to wild-type (WT). During flg22 activation, dynamic phosphorylation events within and outside of the conserved TEY activation loop were observed. In addition, using immunoprecipitation coupled with mass spectrometry (IP-MS), we have identified MPK4 interacting proteins in the absence and presence of flg22. Quantitative proteomic analysis revealed a shift in the MPK4-associated protein network, providing insight into the molecular functions of MPK4 at the systems level.