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Physiology and Biochemistry

Bacteriocin Production by Corynebacterium michiganense. Eddie Echandi, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27607; Phytopathology 66:430-432. Accepted for publication 21 August 1975. DOI: 10.1094/Phyto-66-430.

Corynebacterium michiganense, the causal organism of bacterial canker of tomato, produced bacteriocins in solid media and to a lesser extent in liquid media. Fifty-five of the 96 isolates tested produced bacteriocins as evidenced by the formation of inhibition zones on double-layer agar plates. The 55 bacteriocinogenic strains, were initially classified in 12 groups, and subsequently reclassified in four principal groups. One representative strain was selected from each of the four groups for further study, and to develop a typing scheme. Two of the four selected strains produced thermolabile trypsin-resistant bacteriocins, but bacteriocins from the other two strains were thermostable and trypsin-sensitive. Typing of C. michiganense isolates with the four selected strains permitted differentiation of 10 types which included 96% of the isolates. No correlation was found between bacteriocin type and virulence to tomato plants.

Additional keywords: bacterial canker of tomato, typing by bacteriocin production.