Expression and function assessment of a novel fibrinogen immuno-lectin from Hyalomma rufipes (Acari: Ixodidae)

Lectin is a sugar-binding protein crucial for the innate immunity of ticks and acts as an important antibacterial peptide. When ticks are damaged externally, lectin can initiate a rapid defence mechanism. In this research, a novel immune lectin gene, Hr-lectin , was identified from Hyalomma rufipes . The gene has a size of 852 bp and a molecular weight of 31.509 KDa, encoding 283 amino acids. It is a C-type lectin with a signal peptide and has a theoretical isoelectric point of 6.23. The lectin gene Hr-lectin was analyzed by qPCR. The findings indicate that the expression of lectin was significantly greater in eggs compared to other stages. Similarly, the expression in the ovary was higher than that in other tissues, which was significantly different from other tissues. Additionally, rHr-lectin exhibited a degree of inhibition on Gram-positive bacteria, Gram-negative bacteria, and fungi. During the erythrocyte agglutination experiment, it was observed that rHr-lectin displayed varying agglutination effects on red blood cells. The outcomes of RNAi targeting Hr-lectin exhibited a significant rise in tick mortality rates and a decrease in the average weights of engorged adults and eggs. Regarding morphological characteristics, ticks displayed diminished body size and gray coloration following RNA interference. However, this treatment did not exert any significant influence on the form of the tick eggs.