Positive selection in multiple salivary gland proteins of Anophelinae reveals potential targets for vector control

Abstract

Anopheles is a genus belonging to the Culicidae family, which has great medical importance due to its role as a vector of Plasmodium, the parasite responsible for malaria. From Anopheles functional genomics, great focus has been given to the salivary gland proteins (SGPs) group. This class of proteins is essential to blood-feeding behavior as they have attributes such as vasodilators and anti-clotting properties. Recently, a comprehensive review on Anopheles SGPs was performed, however the authors did not deeply explore the adaptive molecular evolution of these genes. In this context, this work aimed to perform a more detailed analysis of the adaptive molecular evolution of SGPs in Anopheles, carrying out positive selection and gene families evolution analysis on 824 SGPs. Our results show that most SGPs have positively selected sites that can be used as targets in the development of new strategies for vector control. Notably, we were not able to find any evidence of an accelerated shift in the copy-number variation of SGPs compared with other proteins, as suggested in previous works. Significance StatementSalivary gland proteins (SGPs) are essential to blood-feeding behavior in Anopheles and they are the most studied class of proteins in blood-feeding insects. However a proper molecular evolution analysis on SGPs in Anopheles is missing. In our analyses we observed that most SGPs have positively selected sites and we were not able to find any evidence of an accelerated shift in the copy-number of SGPs compared with other proteins, as stated in the literature. Our results can open new venues in the development of new strategies for vector control.