Proteome analysis and identification of symbiosis-related proteins from Medicago truncatula Gaertn. by two-dimensional electrophoresis and mass spectrometry.

Time-course analysis of root protein profiles was studied by two-dimensional gel electrophoresis and silver staining in the model plant Medicago truncatula, inoculated either with the arbuscular mycorrhizal fungus Glomus mosseae or with the nitrogen fixing bacterium Sinorhizobium meliloti. Protein modifications in relation to the development of both symbioses included down- and upregulations, as well as newly induced polypeptides. Matrix assisted laser desorption/ionization-time of flight-mass spectrometry after trypsin digestion clearly identified one polypeptide induced in nodulated roots as a M. truncatula leghemoglobin. Internal sequencing with a quadrupole time-of-flight mass spectrome…