Sinorhizobium melilotiMedicago sativaMedicago truncatulaSymbiosisSinorhizobiumNitrogen FixationMedicagoBacterial ProteinsSinorhizobium frediiRoot Nodules, PlantPlant Root NodulationGene Expression Regulation, BacterialPlant RootsRhizobiumBacteriaRhizobiaceaeGenes, BacterialPolysaccharides, BacterialMolecular Sequence DataMelilotusFabaceaeRhizobium leguminosarumDNA, BacterialLuteolinMutationSequence Analysis, DNAMutagenesis, Insertional