Characterization of Phages Virulent for Sarothamnus scoparius Bradyrhizobia

Four virulent phages—ΦDl, ΦTl, ΦCYT21, and ΦOS6, infective on Sarothamnus scoparius rhizobia—were isolated from the soil and characterized for morphology, host range, rate of adsorption to bacterial cells, and genome size. New phages were separated into two morphological families: Siphoviridae with long, noncontractile tails (ΦDl, ΦTl) and Myoviridae with long, contractile tails (ΦCYT21, ΦOS6). They were also classified into two groups by a host specificity. One of them included viruses (ΦDl and ΦTl) that lysed S. scoparius bradyrhizobia and Bradyrhizobium sp. (Lupinus) strain Dl, and the second one comprised phages (ΦCYT21 and ΦOS6) that parasitized only Scotch broom native microsymbionts. Phages specific for S. scoparius rhizobia were differentiated not only by morphology and host range but also by a genome size that was in the range from 47,583 to 60,098 b.p. An erratum to this article is available at .