Haemaphysalis longicornis salivary gland LC-MSMS

Ticks are notorious carriers of pathogens; these blood-sucking arthropods can spread a variety of deadly diseases. The salivary gland is the main organ in ticks, and this organ begins to develop rapidly when Ixodidae ticks suck blood. When these ticks reach a critical weight, the salivary glands stop developing and begin to degenerate. Specific developmental features of the salivary glands are regulated by multiple factors, such as hormones, proteins and other small molecular substances. In this study, we used iTRAQ quantitative proteomics to study dynamic changes in salivary gland proteins in female Haemaphysalis longicornis at four feeding stages: unfed, partially fed, semi-engorged, and engorged. Through bioinformatics analysis of a large number of proteins, we found that molecular motor- and TCA cycle-related proteins play an important role during the development of the salivary glands. The results of RNAi experiments showed that when dynein, kinesin, isocitrate dehydrogenase, and citrate synthase were knocked down, ticks were unable to suck blood normally. The structure and function of the salivary glands were also significantly affected. In addition, four proteins from H. longicornis were found to have very low homology with those from mammals, including humans. Therefore, it is expected that drugs or antibodies targeting these unique sequences can be designed to kill ticks.