Reactive oxygen species such as hydrogen peroxide (H2O2), play a crucial role as signaling molecules in the establishment and functioning of the nitrogen-fixing legume–Rhizobium symbiosis. The regulation of protein function through oxidative modification has emerged as an important molecular mechanism modulating various biological processes. Protein cysteine residues are known to be sensitive targets of H2O2, in a post-translational modification called sulfenylation. Sulfenylated proteins in theMedicago truncatula–Sinorhizobium melilotisymbiosis were characterized by combining the use of chemical and genetic probes with mass spectrometry analysis. A total of more than 100 proteins belonging to two largest functional groups were identified at different stages of the interaction. Redox state-linked proteins were identified in the early step of the interaction (two days post infection) whereas proteins involved in amino-acid and carbohydrate metabolism in the mature nodule (four weeks post infection). In addition twenty proteins from the bacterial partnerS. meliloti, including some directly involved in nitrogen fixation, were also identified as sulfenylated. These results suggest that sulfenylation may regulate the activity of proteins playing major roles in the development and functioning of the symbiotic interaction.
- Oger E., Marino D., Guigonis J.-M., Pauly N. and Puppo A.(2012) Sulfenylated proteins in the Medicago truncatula-Sinorhizobium meliloti symbiosis. J Proteomics 75, 4102-13.