Distinct epigenomic and transcriptomic modifications associated with Wolbachia-mediated asexuality

Area of Science:

• Microbiology
• Genetics
• Epigenetics

Background:

• Wolbachia are intracellular bacteria impacting host fitness and reproduction.
• In Trichogramma wasps, Wolbachia induces asexual reproduction, enhancing bacterial transmission.
• Previous studies lacked genome-wide epigenomic data controlling for host genetic background.

Purpose of the Study:

• To investigate genome-wide epigenetic modifications in Trichogramma wasps induced by Wolbachia infection.
• To differentiate effects of DNA methylation and gene expression changes.
• To understand host-specific responses and evolutionary patterns.

Main Methods:

• Introgression of Wolbachia-free Trichogramma genomes into infected cytoplasm.
• Curing Wolbachia to isolate infection effects.
• Genome-wide analysis of DNA methylation and gene expression.

Main Results:

• No overlap between differentially methylated and expressed genes, suggesting methylation doesn directly alter expression.
• Differentially methylated genes are conserved; differentially expressed genes are lineage-specific.
• Wolbachia infection increases DNA methylation and reduces gene expression variability.
• Affected genes are involved in oocyte development and chromosome segregation.

Conclusions:

• Wolbachia infection induces distinct epigenetic and transcriptomic changes in Trichogramma wasps.
• DNA methylation and gene expression changes have different evolutionary trajectories.
• Epigenetic modifications impact key cellular processes, highlighting host-specific adaptations.