Isolation and characterization of a temperate bacteriophage specific for Rhodopseudomonas spheroides

The isolation of a temperature phage specific for the photosynthetic bacterium Rhodopseudomonas spheroides is reported. This phage, Rphi-1, establishes a state of lysogeny and can be induced from the prophage state by exposure to mitomycin C or UV irradiation. Mutants of Rphi-1 which grow on a standard laboratory strain (2.4.1) of Rhodopseudomonas spheroides were isolated. Although the original Rphi-1 isolated was chloroform sensitive, the mutant which plates on strain 2.4.1 is chloroform resistant. Rphi-1 does not grow on closely related bacteria, such as Rhodopseudomonas palustris or Rhodopseudomonas capsulata. Rphi-1 mutants forms plaques with the same efficiency whether the plates are incubated under aerobic conditions in the dark or under anaerobic conditions in the light (phototropic conditions).