Kahn Alexandra Katz, Cervantes Jasslin, Almeida Rodrigo P P
Department of Environmental Science, Policy and Management, University of California Berkeley, Berkeley, CA 94720, USA.
Microb Genom. 2025 Jul;11(7). doi: 10.1099/mgen.0.001447.
When pathogens are repeatedly introduced into new environments, host jumps may occur into naïve taxa. Given the magnitude of the global plant trade, this process can lead to frequent disease emergence as interactions between previously isolated pathogens and new plant hosts become possible. is a recurring nuisance. This bacterial pathogen has recently emerged in novel geographic locations infecting a breadth of host plants. An introduction of subsp. from Central America to the USA several hundred years ago has since been the source of outbreaks across the globe. In the USA, particularly in California, the introduced bacterium is frequently found in European grapevine (). In this study, we demonstrated that the introduced strains do not persistently infect . Furthermore, we did not observe an overall increase in the virulence of the introduced strains towards coffee, indicating a lack of hypervirulence. Then, using subsp. whole-genome sequences, 15 from the source region of Costa Rica and 289 from the introduced clade, we tested for traces of adaptation to grapevines. We found both genes and SNPs that are associated with the host shift to grapevines. These results support the hypothesis that a host jump with genetic adaptation occurred following the introduction of the pathogen into the USA.
当病原体反复被引入新环境时，可能会宿主跳跃到未接触过的分类群中。鉴于全球植物贸易的规模，随着以前隔离的病原体与新植物宿主之间的相互作用成为可能，这个过程会导致疾病频繁出现。这是一个反复出现的麻烦事。这种细菌病原体最近在新的地理位置出现，感染了多种宿主植物。几百年前从中美洲引入美国的亚种此后一直是全球疫情爆发的源头。在美国，特别是在加利福尼亚州，这种引入的细菌经常在欧洲葡萄（）中被发现。在这项研究中，我们证明引入的菌株不会持续感染。此外，我们没有观察到引入菌株对咖啡的毒力总体增加，表明不存在高毒力现象。然后，我们使用亚种的全基因组序列，其中15个来自哥斯达黎加的源区域，289个来自引入的进化枝，测试了对葡萄的适应痕迹。我们发现了与宿主向葡萄转移相关的基因和单核苷酸多态性。这些结果支持了病原体引入美国后发生了伴有遗传适应的宿主跳跃这一假设。
