Host Range of Streptomycete Strains Causing Common Scab.

Area of Science:

• Microbiology
• Plant Pathology
• Bacteriology

Background:

• Common scab, caused by Streptomyces species, affects various root vegetables.
• Streptomyces scabies is a primary pathogen of potato common scab.
• Previous research has primarily focused on S. scabies isolated from potatoes.

Purpose of the Study:

• To characterize Streptomyces isolates from carrot common scab lesions.
• To determine the genetic relatedness of carrot isolates to known S. scabies strains.
• To assess the pathogenicity of S. scabies, S. caviscabies, and S. acidiscabies on multiple vegetable crops.

Main Methods:

• Morphological and physiological characterization of Streptomyces isolates.
• DNA-DNA hybridization for genetic relatedness assessment.
• Pathogenicity assays on carrot, potato, radish, beet, turnip, and parsnip.

Main Results:

• Carrot isolates were morphologically and physiologically similar to S. scabies.
• Most carrot isolates showed high DNA relatedness (90%) to S. scabies genetic cluster 1.
• S. scabies isolates were pathogenic on carrots and radishes; S. acidiscabies and S. caviscabies infected multiple crops beyond potatoes.

Conclusions:

• Carrot common scab lesions harbor Streptomyces species closely related to S. scabies.
• Streptomyces scabies, S. acidiscabies, and S. caviscabies exhibit broader pathogenicity than previously known, affecting various root vegetables.
• This highlights the potential for cross-contamination and disease spread among different vegetable crops.