Wolbachiatransinfection inAedes aegypti: A potential gene driver of dengue vectors

Abstract

The endosymbiotic bacteria in the genus Wolbachia are capable of inducing a wide range of reproductive abnormalities in their hosts, including cytoplasmic incompatibility (CI), which could lead to the replacement of uninfected host populations with infected ones. Because of this, Wolbachia have attracted considerable interest as a potential mechanism for spreading disease-blocking transgenes through vector populations. Here we report the establishment of double Wolbachia transinfection by direct adult microinjection of Wolbachia from naturally double-infected Aedes albopictus to Aedes aegypti, the most important mosquito vector of infectious viral diseases, and a mosquito in which natural Wolbachia infections are not known to occur. We further demonstrate that incomplete CI is induced in these double-transinfected mosquitoes. Comparisons of fitness traits between naturally uninfected and transinfected Ae. aegypti lines indicated one significant difference in favor of the latter, namely, an increased number of eggs laid. Levels of CI expression corresponded to the Wolbachia density. There were large differences in relative Wolbachia density between reproductive and nonreproductive tissues in both Ae. albopictus and transinfected Ae. aegypti, except Malpighian tubule, which implied the preferred establishment of Wolbachia within reproductive tissue. Results from a simulation model confirm that population replacement by transinfected Ae. aegypti is possible over time. The establishment of Wolbachia double infections in Ae. aegypti by direct adult microinjection and the demonstration of CI expression in this new host suggest that Wolbachia could be experimentally transferred into vector species and could also be used as a gene-driving system to genetically manipulate vector populations.microinjection ͉ transfer ͉ replacement ͉ tissue tropism ͉ cytoplasmic incompatibility

OPTIMAL CONTROL FOR ENHANCEMENT OF \emph{WOLBACHIA} FREQUENCY AMONG \emph{AEDES AEGYPTI} FEMALES

“…Even though the presence of Wolbachia has never been detected in wild populations of Aedes aegypti mosquitoes [28], many scholars assert that this mosquito species is susceptible to so-called Wolbachia "transinfection", i.e. a deliberate infection of wild mosquito eggs by the Wolbachia pathogen taken from other insect species [21,36].…”

The Virulent Wolbachia Strain wMelPop Efficiently Establishes Somatic Infections in the Malaria Vector Anopheles gambiae

“…Stable (100%) vertical transmission of Wolbachia after injection into adults has been reported for Drosophila melanogaster (7). A similar phenomenon has been reported for Aedes aegypti, but transmission was unstable (approximately 40%) (27). Experiments to determine whether Wolbachia bacteria injected into the hemolymph of adult Anopheles will be transmitted vertically to offspring are ongoing, and if efficient vertical transmission of the symbionts can be established, Wolbachia-based strategies for malaria control should be possible.…”

“…Malaria control is limited by the lack of a vaccine and by parasite and mosquito evolution of drug and insecticide resistance (9,28,31). In light of these problems, there has been a recent concerted effort to develop innovative methods for malaria control based on the genetic modification of Anopheles mosquitoes (transgenesis) or their associated symbiotic microorganisms (paratransgenesis) (5,10,11,13,15,23,25,27,36,37).…”

Detection of Wolbachia Bacteria in Multiple Organs and Feces of the Triatomine Insect Rhodnius pallescens (Hemiptera, Reduviidae)

“…Wolbachia isolates have been found in numerous diseasecarrying insects, such as Culex (12,13), Aedes (27), Glossina (2,26,39), Phlebotominae (16), Cimex (28,29), Ctenocephalides felis (11), and Tunga penetrans (10). It also occurs in parasitic nematodes, such as Onchocerca volvulus, is responsible for the inflammatory reaction that induces blindness (22,24), and has been detected in Brugia malayi (34,36).…”