Abstract
Background: Ticks are important parasites that cause more diseases than most other animal parasites. Haemaphysalis longicornis is used as an experimental animal model for the study of three-host ticks due to its special life cycle and easy maintenance in the laboratory and in its reproduction. The life cycle of H. longicornis goes through a tightly regulated life cycle to adapt to the changing host and environment, and these stages of transition are also accompanied by proteome changes in the body. Methods: In this study, the aim was to use the isobaric tags for relative and absolute quantification (iTRAQ) technique to systematically describe and analyze the dynamic expression of protein and the molecular basis of the proteome of H. longicornis in seven differential developmental stages (eggs, unfed larvae, fed larvae, unfed nymphs, fed nymphs unfed adults, and fed adults). Results: A total of 2,059 proteins were identified, and their expression profiles were classified at different developmental stages. In addition, it was found that tissue and organ development-related proteins and metabolism-related proteins showed that they were involved in different physiological processes throughout the life cycle through the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the differentially expressed proteins (DEPs). More importantly, we found that the upregulated proteins of fed adult ticks were mainly related to yolk absorption, degradation, and ovarian development-related proteins. The abundance of the cuticle proteins in the unfed stages were significantly higher compared with those of the fed ticks in the previous stages. Conclusions: In short, the protein spectrum changes identified in this study provide a reference proteome for future studies of tick functional proteins and provide candidate targets for elucidating tick development and developing new tick control strategies.