Constitutive activation of cellular immunity underlies the evolution of resistance to infection in Drosophila
- University of Cambridge, United Kingdom
- Université de Toulouse, France
Abstract
Organisms rely on inducible and constitutive immune defences to combat infection. Constitutive immunity enables a rapid response to infection but may carry a cost for uninfected individuals, leading to the prediction that it will be favoured when infection rates are high. When we exposed populations of Drosophila melanogaster to intense parasitism by the parasitoid wasp Leptopilina boulardi, they evolved resistance by developing a more reactive cellular immune response. Using single-cell RNA sequencing, we found that immune-inducible genes had become constitutively upregulated. This was the result of resistant larvae differentiating precursors of specialized immune cells called lamellocytes that were previously only produced after infection. Therefore, populations evolved resistance by genetically hard-wiring the first steps of an induced immune response to become constitutive.
Data availability
Unprocessed single cell sequence reads were deposited in the Sequence Read Archive (accession: SRP256887, Bioproject: PRJNA625925). Cell count matrices for all detected genes, cluster identities and processed scRNA-seq results were deposited into Gene Expression Omnibus (accession: GSE148826). The R script used to analyze the scRNA-seq data is available on Github (Repository: dmel_scRNA_hemocyte).
Article and author information
Author details
Funding
Natural Environment Research Council (NE/P00184X/1)
- Alexandre B. Leitão
- Francis M Jiggins
European Molecular Biology Organization (ALT-1556)
- Alexandre B. Leitão
Natural Sciences and Engineering Research Council of Canada (PDF-516634-2018)
- Ramesh Arunkumar
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Leitão et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Constitutive activation of cellular immunity underlies the evolution of resistance to infection in Drosophila
eLife 9:e59095.
https://doi.org/10.7554/eLife.59095
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