Influence of Wolbachia on the fitness of Culex quinquefasciatus

Abstract

Wolbachia pipientis is an obligate intracellular alfa-proteobacteria, endosymbiont in arthropods and nematodes inherited by the mother through the generations. The presence of these bacteria in the germ tissues changes the reproduction of the host, inducing parthenogenesis, males feminization, males killing, cytoplasmic incompatibility (CI) and changes of fitness. Some molecular mechanism from these modifications is based on modulations in genic expression of the host, in other words, the bacteria can suppress or stimulate genes in a way to produce a favorable ambience to the maintenance of the endosymbiosis. Due to these potential manipulations, Wolbachia has been tested as a toll to population control of insect vectors of pathogens. The Culex quinquefasciatus mosquito is naturally infected with Wolbachia in the Neotropical region and is an important vector of several pathogens that affect humans. The presence of the bacteria can cause in the mosquitos cytoplasmic incompatibility, changing the time of oogenese, fecundity and fertility. It is also known that the Wolbachia change the expression of the grauzone gene e there are strong indications that this differential expression induces the CI in Culex quinquefasciatus. In Culex pipiens complex has been observed also that the grauzone gene is an important regulator of the cellular cycle of the oogenesis and spermatogenesis. However, those genetics bases of the phenotype "changed fitness" and CI in the Neotropical model Wolbachia-Cx. quinquefasciatus is still unknown. We propose here to test if the expression of the grauzone homologous gene is different in the Cx. quinquefasciatus (PIN lineage) infected and non-infected. We will also test if the knockdown of that gene in infected females promotes changes in the patterns of the fitness and CI.