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Updated: May 4, 2026
Generation of Monoclonal Cultures from Wolbachia-infected Drosophila melanogaster JW18 Cell Line
Published on: June 27, 2025
Wolbachia variants induce differential protection to viruses in Drosophila melanogaster: a phenotypic and
Ewa Chrostek1, Marta S P Marialva1, Sara S Esteves1
1Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Abstract:
Wolbachia are intracellular bacterial symbionts that are able to protect various insect hosts from viral infections. This tripartite interaction was initially described in Drosophila melanogaster carrying wMel, its natural Wolbachia strain. wMel has been shown to be genetically polymorphic and there has been a recent change in variant frequencies in natural populations. We have compared the antiviral protection conferred by different wMel variants, their titres and influence on host longevity, in a genetically identical D. melanogaster host. The phenotypes cluster the variants into two groups--wMelCS-like and wMel-like. wMelCS-like variants give stronger protection against Drosophila C virus and Flock House virus, reach higher titres and often shorten the host lifespan. We have sequenced and assembled the genomes of these Wolbachia, and shown that the two phenotypic groups are two monophyletic groups. We have also analysed a virulent and over-replicating variant, wMelPop, which protects D. melanogaster even better than the closely related wMelCS. We have found that a ~21 kb region of the genome, encoding eight genes, is amplified seven times in wMelPop and may be the cause of its phenotypes. Our results indicate that the more protective wMelCS-like variants, which sometimes have a cost, were replaced by the less protective but more benign wMel-like variants. This has resulted in a recent reduction in virus resistance in D. melanogaster in natural populations worldwide. Our work helps to understand the natural variation in wMel and its evolutionary dynamics, and inform the use of Wolbachia in arthropod-borne disease control.
Insights
Different Wolbachia variants (wMel) in Drosophila melanogaster offer varying levels of viral protection and impact host lifespan. wMelCS-like variants provide stronger antiviral defense but can reduce host longevity, unlike wMel-like variants.
Area of Science:
- Microbiology
- Genetics
- Evolutionary Biology
Background:
- Wolbachia are intracellular bacteria that confer viral protection to insect hosts.
- The wMel strain in Drosophila melanogaster exhibits genetic polymorphism with recent shifts in variant frequencies.
- Understanding wMel variant dynamics is crucial for insect-borne disease control strategies.
Purpose of the Study:
- To compare antiviral protection, bacterial titers, and host longevity across different wMel variants in a controlled D. melanogaster host.
- To investigate the genomic basis for phenotypic differences among wMel variants.
- To understand the evolutionary dynamics of wMel variants in natural populations.
Main Methods:
- Phenotypic analysis of wMel variants in genetically identical D. melanogaster.
- Genome sequencing and assembly of wMel variants.
- Comparative analysis of wMel variant genomes, focusing on gene amplification in wMelPop.
Main Results:
- wMel variants clustered into two phenotypic groups: wMelCS-like (stronger antiviral protection, higher titers, reduced lifespan) and wMel-like (less protective, more benign).
- wMelPop showed enhanced protection due to a ~21 kb genomic region amplification.
- wMelCS-like variants appear to have been replaced by wMel-like variants in natural populations, leading to reduced virus resistance.
Conclusions:
- Natural variation in wMel strains influences antiviral defense and host fitness.
- Genomic changes, such as gene amplification, underlie phenotypic variation in Wolbachia.
- The replacement of protective wMelCS-like variants by benign wMel-like variants has decreased virus resistance in D. melanogaster populations.
