Mitogen-activated protein kinase 4 regulated metabolic networks

Mitogen-activated protein kinase 4 (MPK4) was first identified as a negative regulator of systemic acquired resistance (SAR). It is also an important kinase that gets involved in other plant biological processes in plants, including cytokinesis, reproduction and photosynthesis. Arabidopsis thaliana mpk4 mutant is a dwarf and sterile. Previous ‘omics’ studies including genomics, transcriptomics and proteomics have revealed new functions of MPK4 in different biological processes. However, due to challenges in metabolomics, no study has focused on metabolomic profiles of the mpk4 mutant and what metabolites and metabolic pathways are potentially regulated by MPK4 are not known. Metabolites are crucial components of plants, which plays an and they play important roles in plant signaling, defense, and growth and development. Here we used targeted and untargeted metabolomics to profile metabolites in wild type (WT) and the mpk4 mutant where we found that in addition to jasmonic acid (JA) and salicylic acid (SA) pathways, MPK4 got involved in polyamine synthesis and photosynthesis. In addition, we also conducted label-free proteomics of the two genotypes. Integration of metabolomics and proteomics data allowed insight into the metabolomic networks that are potentially regulated by MPK4.