Native bacteria block Wolbachia from being passed to mosquito progeny

August 11, 2014
A cross-section of an Anopheles mosquito that has been injected with Wolbachia (red). The blue area represents mosquito DNA. Credit: Jason Rasgon, Penn State

Native bacteria living inside mosquitoes prevent the insects from passing Wolbachia bacteria—which can make the mosquitoes resistant to the malaria parasite—to their offspring, according to a team of researchers.

The team found that Asaia, a type of bacteria that occurs naturally in Anopheles , blocks invasion of Wolbachia into the mosquitoes' germlines—the cells that are passed on through successive generations of an organism—thus stopping the insects from transmitting Wolbachia to their offspring.






The team then used a DNA sequencing technique to identify all of the bacteria —the "microbiome"—in the antibiotic-treated and control mosquitoes. They found that Asaia was specifically reduced by the antibiotic treatment in two different Anopheles species. The scientists then generated an antibiotic-resistant Asaia mutant and supplemented this bacterial mutant back to the antibiotic-treated mosquitoes. They found that after they recolonized the antibiotic-treated mosquitoes with Asaia, Wolbachia was no longer transmitted to offspring and mosquitoes died faster after bloodfeeding.


"With Asaia, we have identified the first specific barrier to Wolbachia maternal transmission," said Rasgon. "We have also shown that Wolbachia can interact with the other members of the mosquito microbiome. Finally, we have a potential hypothesis to explain the decades-old observation of the apparent lack of Wolbachia infection in Anopheles mosquitoes." In the future, the team plans to investigate whether the phenomenon of one species of bacteria blocking maternal transmission of other species holds true across a wider range of . The researchers also hope to exploit their new knowledge to more easily establish stable Wolbachia infections in Anopheles and other mosquitoes.

Explore further: Fighting disease from within the mosquito: New techniques to help halt the spread of disease

More information: Native microbiome impedes vertical transmission of Wolbachia in Anopheles mosquitoes, PNAS,

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