HEME COMPOUNDS AS IRON SOURCES FOR NONPATHOGENIC RHIZOBIUM-BACTERIA

Many animal-pathogenic bacteria can use heme compounds as iron soul ce s, Like these microorganisms, rhizobium strains interact with host org anisms where heme compounds are available. Results presented in this p aper indicate that the use of hemoglobin as an iron source is not rest ricted to animal-pathogenic microorganisms, We also demonstrate that h eme, hemoglobin, and leghemoglobin can act as iron sources under iron- depicted conditions for Rhizobium meliloti 242. Analysis of iron acqui sition mutant strains indicates that siderophore-, heme-, hemoglobin-, and leghemoglobin-mediated iron transport systems expressed by R. mel iloti 242 share at least one component.