STREPTOMYCES CAVISCABIES SP-NOV, FROM DEEP-PITTED LESIONS IN POTATOESIN QUEBEC, CANADA

Eight deep-pitted-scab-inducing streptomycetes isolated from potato le sions in Quebec (Canada) were phenotypically compared with representat ive strains of the principal plant-pathogenic Streptomyces species. Th ese eight strains could be distinguished from representatives of Strep tomyces scabies, Streptomyces aureofaciens, Streptomyces ipomoeae, and Streptomyces acidiscabies on the basis of their morphological or phys iological properties. They were characterized by a gold mycelium on ye ast-malt extract medium and a white mass of spores borne in flexuous c hains. The spores of these organisms were cylindrical and smooth. Thei r cell walls contained the LL-diaminopimelic acid isomer, and their DN A guanine-plus-cytosine content was 71 mol%. The strains which we stud ied did not produce melanin. All of the strains grew on proline or met hionine as a sole nitrogen source and utilized raffinose as a sole car bon source. Bacterial growth was inhibited at pH 4.5. The levels of DN A relatedness between the deep-pitted-scab-inducing strains and strain s of the other plant-pathogenic Streptomyces species were low. We plac e these deep-pitted-scab-inducing strains in a new bacterial species, for which we propose the name Streptomyces caviscabies. The type strai n of this species is strain ATCC 51928.