High proportions of nonpathogenic Streptomyces are associated with common scab-resistant potato lines and less severe disease

被引:24
|
作者
Wanner, Leslie A. [1 ]
机构
[1] USDA ARS, Genet Improvement Fruit & Vegetable Lab, Beltsville, MD 20705 USA
关键词
Streptomyces scabies; Solanum tuberosum; soil microbial ecology; pathogenicity island;
D O I
10.1139/W07-061
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Streptomyces isolates were obtained from potato tubers with common scab lesions from 2 fields over a 3 year period in Minnesota and a 5 year period in Maine. Isolates were obtained from different potato cultivars or breeding lines and types of scab lesions. A majority of isolates could be classified as putative pathogens based on the presence of genes for biosynthesis of the pathogenicity determinant, thaxtomin, but large numbers of streptomycetes lacking genes for thaxtomin biosynthesis (presumably nonpathogenic) were also recovered. Most Streptomyces isolates recovered from raised and pitted lesions were pathogens, whereas mostly nonpathogenic isolates were recovered from unblemished potato skin or nonscab lesions. Fewer pathogenic than nonpathogenic isolates were recovered from the most resistant potato lines. The proportion and diversity of nonpathogenic isolates recovered was higher in Maine than in Minnesota. The association between greater numbers of nonpathogenic Streptomyces and less severe common scab suggests that the interaction between plant genotype and Streptomyces microbial community is important in determining the severity of common scab on potato, and emphasizes the role of complex interactions between plants and microbial populations on and near plant roots in plant disease outcomes.
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页码:1062 / 1075
页数:14
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