Identification and knockdown effect of disulfide isomerase in the Haemaphysalis longicornis (Acari: Ixodidae)

Tick-borne diseases are a leading cause of death and illness worldwide. Disulfide isomerase (DSI) is an essential protein that helps tick bodies form natural protein structures so they can perform their biological functions after engorgement. In this study, we are exploring the role of DSI and present a potential strategy for tick management by interfering with DSI in ticks. HlDSI cDNA contains 1,119 nucleotides encoding 372 amino acids, and its molecular weight is 93.69 kilodaltons. BLAST analysis showed that the HlDSI protein was 99.10% identical to DSI-like proteins of other parasites. We identified the Jeju strain of Haemaphysalis longicornis and characterized its transcriptional and functional status. Each tick’s dsRNA was injected into a female tick and soaked in nymph to further examine its biological functions. RT-PCR and real-time PCR were used to identify and decrease the gene expression of HlDSI RNA interference (RNAi). In adult tick dsRNA-injected groups, HlDSI RNAi significantly impaired tick blood-feeding efficiency and tick viability,and disrupted the molting process in nymphs. According to our analysis, DSI is a significant molecule that is involved in both feeding and reproduction during the tick life cycle,and is therefore a valid target for future tick control strategies.