Recently, our research group analyzed the transcriptome of the salivary glands (SG) of unfed and partially fed Amblyomma sculptum ticks. This species of tick is incriminated as one of the main vectors of Rickettsia rickettsii, etiologic agent of Brazilian spotted fever, for humans. The feeding on blood induced the expression of coding sequences (CDSs) of secreted proteins of various functional classes, such as lipocalins, mucins, protease inhibitors, glycine-rich proteins, metalloproteases, immune system-related proteins and members of the 8.9 kDa superfamily. The superfamily of 8.9 kDa is composed of proteins expressed exclusively in hard ticks that present this molecular mass, and none of its member has been characterized so far. In a preliminary assay, the gene encoding one of the 8.9 kDa family members was silenced by interference RNA (RNAi) in Amblyomma ticks, resulting in a reduction in the engorgement rate of females relative to the control gene after 72 h of (data not shown). Based on this information, members belonging to this family are likely to play an important role during the feeding of ticks. Thus, the main objective of this project is to evaluate the effect of gene silencing of 8.9 kDa family members on engorgement and reproduction of the A. sculptum tick. The functional characterization of genes modulated by the blood feeding of the A. sculptum tick may contribute to the development of new strategies for its control and also for the control of R. rickettsii.
News published in Agência FAPESP Newsletter about the scholarship: