Title: Control of Anopheles albimanus mosquitoes: improving vector control with a RNAi based strategy
Authors: Mabel Taracena (1,2), Andrea Ramos (2), Pamela Flores (1,2), Pamela Pennington (1,2)
Affiliations: (1) Universidad del Valle de Guatemala, (2) Centro de Estudios en Biotecnología, Universidad del Valle de Guatemala
Abstract: Tropical diseases are a long standing companion for humanity. The complexity of the vectors and parasites life cycles requires deep understanding of their biology and behavior in order to design effective tools to reduce and eventually eliminate transmission. Guatemala is one of the many Latin American countries with active transmission of Malaria, and Anopheles albimanus is the main vector in the zone. One of the strategies with probably more probabilities to succeed is the Sterile Insect Technique (SIT), and one of the key points to be improved is the fitness of the sterile males. In the 1970s, a successful evaluation of a chemosterilization method was performed in El Salvador for Anopheles albimanus, the primary vector of malaria in Central America. If instead of radiation, an RNAi-rearing of the larvae achieves the production of sterile males, that would improve the fitness and reduce the safety hazards of radiation. We propose to develop a new generation of mosquito sterilization tools based on the oral delivery of bacteria expressing dsRNA specific for spermatogenesis genes expressed during larval development. We selected the An. albimanus homologues of boule and zpg, for their importance in meiosis and sperm development. We studied their expression during the life cycle of the mosquito. We designed a protocol for oral delivery of dsRNA produced by bacteria. We also developed a protocol to evaluate male sterility in the laboratory. After testing several gene fragments, we obtained stable inducible inserts of ~200 bp for both genes. We are currently designing long dsRNA and hairpin-dsRNA, to test silencing efficiencies with alternative bacterial expression strategies. We will use the tools and protocols thus far developed to feed larvae with bacteria expressing dsRNA and evaluate the silencing effects on fecundity.