Wolbachia is capable of regulating host reproduction, and thus of great significance in preventing the spread of insect-borne diseases and controlling pest insects. The fruit fly Drosophila melanogaster is an excellent model insect for understanding Wolbachia-host interactions. Here we artificially transferred the wCcep strain from the rice moth Corcyra cephalonica into D. melanogaster by microinjection. Crossing experiments indicated that wCcep could induce a high level of CI in the phylogenetically distant host D. melanogaster and imposed no negative fitness costs on host development and fecundity. Based on quantitative analysis, the titres of wCcep and the native wMel strain were negatively correlated, and wCcep could only be transmitted in the novel host for several generations (G0 to G4) after transinfection. Transcriptome sequencing indicated that the invading wCcep strain induced a significant immune- and stress-related response from the host. An association analysis between the expression of immune genes attacin-D/edin and the titre of Wolbachia by linear regression displayed a negative correlation between them. Our study suggest that the intrusion of wCcep elicited a robust immune response from the host and incurred a competitive exclusion from the native Wolbachia strain, which resulted in the failure of its establishment in D. melanogaster.

中文翻译：

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由于免疫和排斥反应，来自蛾的入侵沃尔巴克菌株未能在果蝇中建立

沃尔巴克氏菌具有调节宿主繁殖的能力，因此在预防虫媒疾病传播和防治害虫方面具有重要意义。果蝇 Drosophila melanogaster 是一种很好的模型昆虫，用于了解 Wolbachia 与宿主的相互作用。在这里，我们通过显微注射将来自水稻蛾 Corcyra cephalonica 的 wCcep 菌株人工转移到 D. melanogaster 中。交叉实验表明，wCcep 可以在系统发育较远的宿主黑腹果蝇中诱导高水平的 CI，并且不会对宿主的发育和繁殖力产生负面的适应性成本。根据定量分析，wCcep 的滴度与天然 wMel 菌株呈负相关，并且 wCcep 转染后只能在新宿主中传播几代（G0 至 G4）。转录组测序表明，入侵的 wCcep 菌株诱导宿主产生显着的免疫和应激相关反应。通过线性回归分析免疫基因attacin-D/edin的表达与Wolbachia滴度之间的关联分析显示它们之间呈负相关。我们的研究表明，wCcep 的入侵引起了宿主强烈的免疫反应，并引起了本地 Wolbachia 菌株的竞争性排斥，导致其在 D. melanogaster 中的建立失败。