Cordyceps and Beauveria infections drive species-specific microbiome dysbiosis in the mosquito Aedes aegypti

Résumé fourni par la source

With the rising prevalence of vector-borne diseases and insecticide resistance in mosquitoes, alternative vector control strategies are urgently needed. Fungal entomopathogens offer a promising approach with a decreased likelihood of resistance development in mosquito populations. However, the mechanisms by which each fungus contributes to host mortality remain poorly understood, and the potential role of microbiome disruption as a secondary pathogenic mechanism has received limited attention. We evaluated the impact of four entomopathogenic fungal species ( Beauveria bassiana, Cordyceps javanica, C. cateniannulata , and C. amoenerosea ) on the microbiome of the yellow fever mosquito ( Aedes aegypti ) colonized with a defined, field-derived bacterial community. Whole-body bacterial communities were profiled using high throughput 16S rRNA amplicon sequencing, and community structure was assessed through alpha diversity metrics, beta diversity analysis, hierarchical clustering, and linear discriminant analysis effect size (LEfSe). All four fungal species successfully infected the mosquito; however, their effects on the mosquito microbiome were species-specific. Cordyceps javanica and C. cateniannulata reduced community evenness without significantly affecting species richness, a pattern consistent with a dominance-driven dysbiosis rather than broad bacterial loss. Infections by C. amoenerosea significantly increased total bacterial load and drove strong enrichment of the opportunistic genus Pandoraea , suggesting epithelial disruption or immune dysregulation as possible contributing factors. Beta diversity analysis indicated partial community-level restructuring across all fungal infections. B. bassiana showed a distinct genus-level compositional response, with enrichment of core symbiotic taxa and depletion of Chryseobacterium and Kluyvera , which was different from the Enterobacteriaceae-dominated shifts seen across infections with Cordyceps species. LEfSe analysis identified Kluyvera and Burkholderia as the strongest genus-level discriminators of infection state, suggesting potential utility as microbiome-based indicators of successful fungal colonization. These key findings were independently validated using EdgeR and batch-corrected MaAsLin2 analyses, with Pandoraea enrichment under C. amoenerosea and Burkholderia depletion under C. cateniannulata confirmed by both methods. Taken together, these results show that entomopathogenic fungi restructure the Ae. aegypti microbiome in a species-specific manner, inducing community destabilization and opportunistic bacterial enrichment that likely contribute to the detrimental effects of fungal infection. These results provide a mechanistic insights for the selection and development of fungal biopesticides for mosquito control.

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