Comparison of protein-lipopolysaccharide complexes produced by pathogenic and non-pathogenic strains of Verticillium dahliae Kleb. from potato☆

Abstract Phytotoxic protein-lipopolysaccharide (PLP) complexes were isolated from dialyzed culture fluids of a pathogenic strain of Verticillium dahliae ; PLP complexes which lack phytotoxic activity were isolated from a mutant non-pathogenic strain of the fungus. A comparison of profiles of the wild-type and mutant PLP eluting from an Agarose A-5 m column revealed quantitative differences between the 2 major protein peaks of each strain. The corresponding peaks of the 2 strains had similar molecular weights and in gel immunodiffusion were antigenically indistinguishable, but differences between them were seen in their chemical composition when analysed for protein, lipid and carbohydrate content. Antiserum prepared against the components of peak 1 from the pathogenic strain reacted with an antigen in extracts of Verticillium -infected potato plant tissue which was apparently identical to a moiety produced by the pathogen in culture.