Two New Bacteriophages for Bacterial Pathogens of the Bean

Abstract

THE bacterial pathogens of beans are widespread all over the world. In most cases four species of bacterium are the main causal organisms: Pseudomonas phaseolicola (Burkholder) Dowson, Xanthomonas phaseoli (E.F. Smith) Dowson, Corynebacterium flaccumfaciens (Hedges) Dowson, and Xanthomonas phaseoli var. fuscans (Burkholder) Starr et Burkholder. The symptoms, on the seed, of the diseases caused by these four bacteria are similar to such an extent that they can be identified only by means of laboratory methods. Katznelson et al. ¹ succeeded in isolating the phages for P. phaseolicola and X. phaseoli. The Canadian authors worked out a rapid phage-count method using these two phages. By means of this procedure they were able to detect the halo-blight organism (P. phaseolicola) and the common blight bacterium (X. phaseoli) in beans. In order to apply this method for all the four important pathogens of beans, it was necessary to isolate also the phages for C. flaccumfaciens and X. phaseoli var. fuscans. This work, which was undertaken because C. flaccumfaciens and X. phaseoli var. fuscans are the major causative agents of bean diseases in Hungary, was recently carried out in our laboratory.