Lysogeny in Rhizobium Leguminosarum and Rh. Trifolii

Abstract

Seven lysogenic strains-three of Rh. legumino8urum and four of Rh. trifoliiwere identified among a total of 54 strains from these two species and Rh. phaseoli. The Rh.leguminosarum strains may be multiply lysogenic; two of them also produce lethal agents resembling bacteriocins in their effect. Lysogeny was confumed by standard criteria of ultraviolet light inducibility, self.immunity, and reductive ability. Lysogenic conversion involving symbiotic characteristics was not observed. A minimum of six different temperate phages and two clear-plaque-forming variant phages were identified. The host range includes strains of the above three rhizobial species, but not of Rh. melilotii. Variation in host specificity of some phages following host passage is under investigation.