Biological control of crown gall through bacteriocin production

Abstract

Crown gall caused by Agrobacterium radiobacter var. tumefaciens can be controlled biologically by a closely related non-pathogenic bacterium, A. radiobacter var. radiobacter. The control mechanism operates through the production of a bacteriocin by the controlling organism. With one exception, pathogenic strains sensitive to the bacteriocin are effectively controlled. The exception is a strain which produces another bacteriocin that inhibits the controlling organism. Pathogenic strains insensitive to the bacteriocin produced by the controlling organism are not subject to biological control. When a bacteriocin-sensitive pathogenic strain is exposed to bacteriocin, resistant colonies develop but these are no longer pathogenic.