Phosphorylation profiling of phytocytokine versus MAMP signaling reveals systemin-specific signaling events

Plasma membrane-localized pattern recognition receptors (PRRs) percieve host-derived phytocytokines (e.g. systemin) and microbe-associated molecular patterns (MAMPs; e.g. flg22 and chitin). Upon ligand binding, activation of PRRs induces similar early phosphorylation-regulated responses including extracellular alkalization and reactive oxygen species burst. However, despite similar early signaling events, the downstream responses are distinct: MAMPs trigger plant innate immunity, and the wound response is elicited by systemin. Therefore, the question arises as to how systemin-mediated responses differ from that of MAMPs, and how specificity is achieved. Here we used a Solanum peruvianum suspension cell culture to analyze phospho-proteomic responses triggered by 20nM flg22 and 15 ug/mL chitin compared to mock(water) treatment. Samples were analyzed in a time series of 0,1,2,5,15 and 45 min after elicitor treatment in six biological replicates. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE27 partner repository with the dataset identifier PXD054229 and PXD062081.