The genus Streptomyces includes several phytopathogenic species that cause common scab, a devastating disease of tuber and root crops, in particular potato. The diversity of species that cause common scab is unknown. Likewise, the genomic context necessary for bacteria to incite common scab symptom development is not fully characterized. Here, we phenotyped and sequenced the genomes of five strains from a poorly studied Streptomyces lineage. These strains form a new species-level group. When genome sequences within just these five strains are compared, there are no polymorphisms of loci implicated in virulence. Each genome contains the pathogenicity island that encodes for the production of thaxtomin A, a phytotoxin necessary for common scab. Yet, not all sequenced strains produced thaxtomin A. Strains varied from nonpathogenic to highly virulent on two hosts. Unexpectedly, one strain that produced thaxtomin A and was pathogenic on radish was not aggressively pathogenic on potato. Therefore, while thaxtomin A biosynthetic genes and production of thaxtomin A are necessary, they are not sufficient for causing common scab of potato. Additionally, results show that even within a species-level group of Streptomyces strains, there can be aggressively pathogenic and nonpathogenic strains despite conservation of virulence genes.

属链霉菌包括若干植物致病物种引起普通疮痂病，块茎和根茎作物的破坏性疾病，特别是马铃薯。引起普通sc疮的物种的多样性是未知的。同样，细菌引起常见sc疮症状发展所必需的基因组背景也没有得到充分表征。在这里，我们对来自研究不足的链霉菌的五种菌株的基因组进行了表型分析和测序血统。这些菌株形成了一个新的物种水平群。当仅比较这五个菌株中的基因组序列时，没有与毒力有关的基因座多态性。每个基因组都包含一个致病岛，该岛编码产生thaxtomin A（一种普通sc疮所必需的植物毒素）。然而，并非所有测序的菌株都产生了thaxtominA。菌株在两个宿主上从非致病性到高毒力不等。出乎意料的是，一种产生thaxtomin A并在萝卜上致病的菌株对马铃薯没有致病性。因此，尽管thaxtomin A的生物合成基因和产生thaxtomin A必不可少，但它们不足以引起马铃薯的常见结ab。此外，结果表明，即使在物种级别的链霉菌群内 毒株，尽管有毒力基因保守，但仍可能有攻击性和非致病性的菌株。