Stress conditions promote Leishmania hybridization in vitro marked by expression of the ancestral gamete fusogen HAP2 as revealed by single-cell RNAseq
- Institut Pasteur, France
- National Institute of Allergy and Infectious Diseases, United States
- University of Colombo, Sri Lanka
Abstract
Leishmania are protozoan parasites transmitted by the bite of sand fly vectors producing a wide spectrum of diseases in their mammalian hosts. These diverse clinical outcomes are directly associated with parasite strain and species diversity. Although Leishmania reproduction is mainly clonal, a cryptic sexual cycle capable of producing hybrid genotypes has been inferred from population genetic studies, and directly demonstrated by laboratory crosses. Experimentally, mating competence has been largely confined to promastigotes developing in the sand fly midgut. The ability to hybridize culture promastigotes in vitro has been limited so far to low efficiency crosses between two L. tropica strains, L747 and MA37, that mate with high efficiency in flies. Here, we show that exposure of promastigote cultures to DNA damage stress produces a remarkably enhanced efficiency of in vitro hybridization of the L. tropica strains, and extends to other species, including L. donovani, L. infantum, and L. braziliensis, a capacity to generate intra- and interspecific hybrids. Whole genome sequencing and total DNA content analyses indicate that the hybrids are in each case full genome, mostly tetraploid hybrids. Single-cell RNA sequencing of the L747 and MA37 parental lines highlights the transcriptome heterogeneity of culture promastigotes and reveals discrete clusters that emerge post-irradiation in which genes potentially involved in genetic exchange are expressed, including the ancestral gamete fusogen HAP2. By generating reporter constructs for HAP2, we could select for promastigotes that could either hybridize or not in vitro. Overall, this work reveals that there are specific populations involved in Leishmania hybridization associated with a discernible transcriptomic signature, and that stress facilitated in vitro hybridization can be a transformative approach to generate large numbers of hybrid genotypes between diverse species and strains.
Data availability
The raw sequence data containing reads from the 51 WGS samples and 8 scRNA-seq samples sequenced are deposited in the SRA database with Accession numbers PRJNA756557 and PRJNA756571, respectively.
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raw sequence data containing reads from the 51 WGS samplesNCBI Sequence Read Archive, PRJNA756557.
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scRNA-seq samples sequencedNCBI Sequence Read Archive, PRJNA756571.
Article and author information
Author details
Nadira D Karunaweeera
Funding
Division of Intramural Research, National Institute of Allergy and Infectious Diseases
- Andrea Paun
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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Stress conditions promote Leishmania hybridization in vitro marked by expression of the ancestral gamete fusogen HAP2 as revealed by single-cell RNAseq
eLife 11:e73488.
https://doi.org/10.7554/eLife.73488
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