日本各地から分離されたジャガイモそうか病菌の多様性

抄録

Streptomyces strains isolated from potato scab and potato russet scab lesions in Japan were characterized by morphological and physiological analyses, DNA homology, and restriction fragment length polymorphisms (RFLPs). They were divided into three groups based on spore chain morphology. Strains from potato scab lesions exhibited either a spiral spore chain morphology (S-type) or a flexuous spore chain morphology (F-type), while strains from potato russet scab lesions showed a retinaculum-apertum spore chain morphology (RA-type) exclusively. Although the S-type produced a melanoid pigment, the F- and RA-type did not. Both the S-type and F-type were divided into two groups based on DNA homology study and also RFLP analysis with suberin-degradative esterase gene sequences as probes, resulting in four separate groups. These groups coincided with geographic origin, as the S-type isolated from the Kyushu and Honshu areas were different from the S-type from the Hokkaido area, and the F-type isolated from the Kyushu area was distinct from the F-type from the Hokkaido area. From DNA homology experiments, the S-type isolated from the Kyushu and Honshu areas, and the F-type isolated from the Kyushu area were identified as S. scabies and S. acidiscabies, respectively. The present study confirms that in Japan, potato scab is caused by at least four genetically distinct Streptomyces species, including S. scabies and S. acidiscabies.