Department of Sustainable Agro-Ecosystems and Bioresources, Fondazione Edmund Mach, San Michele all'Adige, Italy.
Centre of Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria.
Sci Rep. 2017 Nov 1;7(1):14815. doi: 10.1038/s41598-017-13808-z.
Ability to distinguish between closely related Wolbachia strains is crucial for understanding the evolution of Wolbachia-host interactions and the diversity of Wolbachia-induced phenotypes. A useful model to tackle these issues is the Drosophila suzukii - Wolbachia association. D. suzukii, a destructive insect pest, harbor a non-CI inducing Wolbachia 'wSuz' closely related to the strong CI-inducing wRi strain. Multi locus sequence typing (MLST) suggests presence of genetic homogeneity across wSuz strains infecting European and American D. suzukii populations, although different Wolbachia infection frequencies and host fecundity levels have been observed in both populations. Currently, it is not clear if these differences are due to cryptic wSuz polymorphism, host background, geographical factors or a combination of all of them. Here, we have identified geographical diversity in wSuz in D. suzukii populations from different continents using a highly diagnostic set of markers based on insertion sequence (IS) site polymorphism and genomic rearrangements (GR). We further identified inter-strain diversity between Wolbachia infecting D. suzukii and its sister species D. subpulchrella (wSpc). Based on our results, we speculate that discernible wSuz variants may associate with different observed host phenotypes, a hypothesis that demands future investigation. More generally, our results demonstrate the utility of IS and GRs in discriminating closely related Wolbachia strains.
区分密切相关的沃尔巴克氏体菌株对于理解沃尔巴克氏体-宿主相互作用的进化和诱导沃尔巴克氏体表型的多样性至关重要。一个有用的模型是研究果蝇与沃尔巴克氏体的相互关系。果蝇是一种破坏性的害虫，携带一种非 CI 诱导的沃尔巴克氏体 'wSuz'，与强 CI 诱导的 wRi 菌株密切相关。多位点序列分型 (MLST) 表明，感染欧洲和美洲果蝇的 wSuz 菌株在遗传上具有同质性，尽管在这两个种群中观察到不同的沃尔巴克氏体感染频率和宿主繁殖力水平。目前尚不清楚这些差异是由于 wSuz 的隐性多态性、宿主背景、地理因素还是它们的组合造成的。在这里，我们使用基于插入序列 (IS) 位点多态性和基因组重排 (GR) 的高度诊断性标记，鉴定了来自不同大陆的果蝇种群中 wSuz 的地理多样性。我们进一步鉴定了感染果蝇及其姐妹种 D. subpulchrella (wSpc) 的沃尔巴克氏体之间的菌株间多样性。基于我们的结果，我们推测可识别的 wSuz 变体可能与不同的观察到的宿主表型相关，这一假设需要进一步研究。更普遍地说，我们的结果表明 IS 和 GR 可用于区分密切相关的沃尔巴克氏体菌株。
