LYSOGENY IN A STRAIN OF XANTHOMONAS GAMPESTRIS

Abstract

Fourteen bacterial strains representing eight so-called species of phytopathogenic xanthomonads were tested for lysogeny both before and after treatments known to induce phage development in lysogenic bacteria. Only a single temperate phage, of restricted host range, was found. Evidence suggestive of defective lysogeny was found in a number of cases.Strain P165, Xanthomonas campestris, when treated with antibiotic Mitomycin C at a concentration of 0.1,ug/ml in nutrient broth, produced phage particles active on strain P12S, X. campestris. No other sensitive strains were found among the 81 tested, representing 22 species of Xanthomonas. This phage (P165/P125) produced small turbid plaques, 0.6 mm to 0.8 mm in diameter, with indefinite margins. Evidence for the lysogenization of P125 strain by this phage was found. Clear plaques were sometimes found in lawns of lysogenized cells of P12S. These were presumably derived from phage mutants with increased virulence. When examined under the electron microscope, the phage particles were semispherical, approximately 65 m/x in diameter with rudimentary tails.