Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Brisbane, Australia.
Department of Agriculture and Fisheries, Brisbane, Australia.
Pest Manag Sci. 2020 Jul;76(7):2441-2452. doi: 10.1002/ps.5785. Epub 2020 Feb 24.
Haematobia spp., horn flies (HF) and buffalo flies (BF), are economically important ectoparasites of dairy and beef cattle. Control of these flies relies mainly on treating cattle with chemical insecticides. However, the development of resistance to commonly used compounds is compromising the effectiveness of these treatments and alternative methods of control are required. Wolbachia are maternally transmitted endosymbiotic bacteria of arthropods that cause various reproductive distortions and fitness effects, making them a potential candidate for use in the biological control of pests. The first step towards this is the establishment and adaptation of xenobiotic infections of Wolbachia in target host cell lines.
Here, we report the successful establishment of a continuous HF cell line (HIE-18) from embryonic cells and its stable transinfection with Wolbachia strains wAlbB native to mosquitoes, and wMel and wMelPop native to Drosophila melanogaster. HIE-18 cells were typically round and diploid with ten chromosomes (2n = 10) or tetraploid with 20 chromosomes (4n = 20), with a doubling time of 67.2 h. Wolbachia density decreased significantly in HIE-18 cells in the first 48 h of infection, possibly due to overexpression of antimicrobial peptides through the Imd immune signalling pathway. However, density recovered after this time and HIE-18 cell lines stably infected with the three strains of Wolbachia have now each been subcultured more than 50 times as persistently infected lines.
The amenability of HF cells to infection with different strains of Wolbachia and the establishment of stable sustaining infections suggest the potential for use of Wolbachia in novel approaches for the control of Haematobia spp. Further, the availability of the HIE-18 cell line will provide an important resource for the study of genetics, host-parasite interactions and chemical resistance in Haematobia populations. © 2020 Society of Chemical Industry.
血蝇属（Haematobia）、角蝇（HF）和牛蝇（BF）是奶牛和肉牛的重要经济寄生性外寄生虫。这些蝇类的防治主要依赖于对牛进行化学杀虫剂处理。然而，这些处理方法的效果受到了普遍使用的化合物产生抗药性的影响，因此需要替代的控制方法。沃尔巴克氏体是节肢动物的母系共生菌，它会导致各种生殖畸形和适应性降低，因此成为害虫生物防治的潜在候选物。实现这一目标的第一步是建立和适应沃尔巴克氏体在目标宿主细胞系中的外来生物感染。
本研究报告了成功地从胚胎细胞中建立了一种连续的 HF 细胞系（HIE-18），并稳定转染了蚊源的 Wolbachia 菌株 wAlbB、果蝇源的 wMel 和 wMelPop。HIE-18 细胞通常呈圆形和二倍体，有 10 条染色体（2n = 10），或四倍体，有 20 条染色体（4n = 20），倍增时间为 67.2 小时。在感染的前 48 小时内，HIE-18 细胞中的沃尔巴克氏体密度显著下降，这可能是由于通过 Imd 免疫信号通路过度表达抗菌肽所致。然而，在此时间之后，密度得到了恢复，现在已经将三种沃尔巴克氏体菌株稳定感染的 HIE-18 细胞系作为持续感染的细胞系进行了超过 50 次的亚培养。
HF 细胞易于感染不同菌株的沃尔巴克氏体，并且能够建立稳定的持续感染，这表明沃尔巴克氏体在控制 Haematobia spp. 的新方法中有应用潜力。此外，HIE-18 细胞系的可用性将为 Haematobia 种群的遗传学、宿主-寄生虫相互作用和化学抗性的研究提供重要资源。 © 2020 英国化学学会。
