CHARACTERIZATION OF STREPTOMYCETES CAUSING DEEP-FITTED SCAB OF POTATOIN QUEBEC, CANADA

Nine streptomycete strains that cause deep-pitted scab of potato were characterized by performing 138 physiological and morphological tests. A numerical analysis revealed that the deep-pitted scab-inducing orga nisms were related to strains belonging to cluster 1 of Williams et al . (Streptomyces albidoflavus). The levels of similarity between the de ep-pitted scab-inducing strains and strains of Streptomyces scabies an d Streptomyces acidiscabies were low (52 and 54%, respectively). The f atty acid profiles of the deep-pitted scab-inducing organisms differed considerably from those of S. scabies and S. acidiscabies. The deep-p itted scab-inducing bacteria were characterized by the predominance in their profiles of the 15:0 anteiso, 15:0 iso, 16:0 iso, 16:0, and 17: 0 anteiso acids. The results of physiological characterization experim ents, a fatty acid analysis, and whole-cell protein electrophoresis sh owed that the deep-pitted scab-inducing strains characterized in this study formed a relatively homogeneous group. These pathogenic strains could also be differentiated from S. scabies by their high cellulolyti c and proteolytic activities.