VIEW ARTICLE

Comparison of Plant-Pathogenic Pseudomonads by Disc-Gel Electrophoresis. B. C. Palmer, Assistant Professor, Department of Life Sciences, Southern Utah State College, Cedar City 84720; H. R. Cameron, Professor, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Phytopathology 61:984-986. Accepted for publication 18 March 1971. DOI: 10.1094/Phyto-61-984.

Thirty-eight isolates representing Pseudomonas syringae, P. morsprunorum, P. phaseolicola, P. lachrymans, P. glycinea, P. fluorescens, and P. aeruginosa were compared using disc-gel electrophoresis and physiological and pathogenicity tests. Electrophoretic data confirmed the close relationship among the oxidase-negative plant pathogens, as well as their distinction from the saprophytic species. Protein band patterns for P. glycinea, P. phasiolicola, and P. morsprunorum were quite similar, and could be distinguished from the other species by the occurrence of a densely staining band above the two frontal bands. Patterns of P. syringae and P. lachrymans were similar in many respects, and were distinguishable from the others. Pseudomonas fluorescens and P. aeruginosa were distinct from any of the other isolates tested. The data support the placing of the oxidase-negative plant pathogens in a single taxospecies. However, distinctions within this group can be made at the subspecies level by some physiological tests and gel electrophoresis.