Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, P. R. China.
Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.
Pest Manag Sci. 2020 Aug;76(8):2736-2745. doi: 10.1002/ps.5821. Epub 2020 Apr 8.
Varroa destructor is considered a major cause of honeybee (Apis mellifera) colony losses worldwide. Although V. destructor mites exhibit preference behavior for certain honeybee lifecycle stages, the mechanism underlying host finding and preference remains largely unknown.
By using a de novo transcriptome assembly strategy, we sequenced the mature daughter V. destructor mite transcriptome during infestation of different stages of honeybees (brood cells, newly emerged bees and adult bees). A total of 132 779 unigenes were obtained with an average length of 2745 bp and N50 of 5706 bp. About 63.1% of the transcriptome could be annotated based on sequence homology to the predatory mite Metaseiulus occidentalis proteins. Expression analysis revealed that mature daughter mites had distinct transcriptome profiles after infestation of different honeybee stages, and that the majority of the differentially expressed genes (DEGs) of mite infesting adult honeybees were down-regulated compared to that infesting the sealed brood cells. Gene ontology and KEGG pathway enrichment analyses showed that a large number of DEGs were involved in cellular process and metabolic process, suggesting that Varroa mites undergo metabolic adjustment to accommodate the cellular, molecular and/or immune response of the honeybees. Interestingly, in adult honeybees, some mite DEGs involved in neurotransmitter biosynthesis and transport were identified and their levels of expression were validated by quantitative polymerase chain reaction (qPCR).
These results provide evidence for transcriptional reprogramming in mature daughter Varroa mites during infestation of honeybees, which may be relevant to understanding the mechanism underpinning adaptation and preference behavior of these mites for honeybees. © 2020 Society of Chemical Industry.
瓦螨被认为是全球蜜蜂（Apis mellifera）蜂群损失的主要原因。尽管瓦螨若螨对某些蜜蜂生命周期阶段表现出偏好行为，但宿主发现和偏好的机制在很大程度上仍然未知。
通过使用从头转录组组装策略，我们对不同阶段的蜜蜂（幼虫细胞、新出房的蜜蜂和成年蜜蜂）上寄生的成熟雌性瓦螨进行了转录组测序。共获得了 132779 个 unigenes，平均长度为 2745bp，N50 为 5706bp。大约 63.1%的转录本可以根据与捕食性螨类 Metaseiulus occidentalis 蛋白的序列同源性进行注释。表达分析显示，成熟雌性瓦螨在寄生不同蜜蜂阶段后具有明显的转录组谱，寄生成年蜜蜂的大多数差异表达基因（DEGs）与寄生封盖幼虫细胞的相比下调。基因本体论和 KEGG 通路富集分析表明，大量 DEGs 参与细胞过程和代谢过程，这表明瓦螨经历了代谢调整以适应蜜蜂的细胞、分子和/或免疫反应。有趣的是，在成年蜜蜂中，鉴定出一些与神经递质生物合成和转运有关的螨 DEGs，并通过定量聚合酶链反应（qPCR）验证了它们的表达水平。
这些结果为成熟雌性瓦螨在寄生蜜蜂过程中的转录重编程提供了证据，这可能有助于理解这些螨虫对蜜蜂的适应和偏好行为的机制。 © 2020 化学工业协会。
