Sinorhizobium melilotiSymbiosisNitrogen FixationRhizobiumSinorhizobiumMedicago sativaRhizobium leguminosarumSinorhizobium frediiMedicago truncatulaPlant Root NodulationMedicagoRoot Nodules, PlantBacterial ProteinsRhizobium etliRhizobiaceaeGene Expression Regulation, BacterialFabaceaeGenes, BacterialPlant RootsPolysaccharides, BacterialMolecular Sequence DataDNA, BacterialMelilotusRhizobium tropiciLuteolinSequence Analysis, DNAMutagenesis, InsertionalGenome, BacterialBradyrhizobiumMutationGenetic Complementation TestPlants, MedicinalPhylogeny