Authors

A Bacigalupo³; C Hernández⁴; JD Ramírez⁴; S Pita⁵; C Gyhrs⁹; B Cheaib¹⁰; AG Villacís¹; MJ Grijalva⁶; K Brunker³; C Botto-Mahan⁷; MA Varas⁷; ML Allende⁸; PE Cattan²; KR Elmer³; MS Llewellyn³;  ¹ Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Ecuador;  ² Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Chile;  ³ School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, UK;  ⁴ Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Colombia;  ⁵ Facultad de Ciencias, Universidad de la República, Uruguay;  ⁶ Infectious and Tropical Disease Institute, Heritage College of Osteopathic Medicine, Ohio University, United States;  ⁷ Facultad de Ciencias, Universidad de Chile, Chile;  ⁸ Millenium Institute Center for Genome Regulation, Universidad de Chile, Chile;  ⁹ College of Medical, Veterinary and Life Sciences, University of Glasgow, UK;  ¹⁰ Centre for infectious diseases, Universitätsklinikum Heidelberg, Germany

Discussion

Chagas disease is the most important parasitosis on the American continent, with more than 300,000 new human cases and 12,000 deaths each year. New tools are required to accelerate the interruption of Trypanosoma cruzi domiciliary vectorial transmission by triatomines. Here, we provide multiple new genomic resources for triatomine species, including non-hematophagous predatory sister taxa, with the aim of elucidating the process of adaptation to blood feeding within Reduviidae (Hemiptera: Heteroptera).

We gathered samples from species across Latin America, extracted the DNA and performed long-read (ONT) and short-read (Illumina) sequencing, assembly and annotation. The annotation pipeline included a homology-based annotation with Gemoma, using available annotations for Rhodnius prolixus, Triatoma rubrofasciata, Cimex lectularius and Acyrthosiphon pisum. The Gemoma annotation was included as input to the GenSAS pipeline, along with available protein and RNA-seq data. Mitogenomes were generated using Novoplasty and annotated with MITOS2 in Proksee, and the phylogeny of triatomine species within Hemiptera was obtained using OrthoFinder.

As results, we produced eight new whole genome assemblies, for six species without previous genomes: Belminus herreri (1.1 Gbp, GC 34.1%, N 0.9%), Mepraia spinolai (977.1 Mbp, GC 33.8%, N 0.6%), Panstrongylus geniculatus (1.2 Gbp, GC 34.7%, N 9.1%), Psammolestes arthuri (542.9 Mbp, GC 33.9%, N 1.8%), Rhodnius brethesi (550.7 Mbp, GC 33.5%, N 1.8%) and Rhodnius ecuadoriensis (583.8 Mbp, GC 33.9%, N 4.2%), and for two species with available but very fragmented assemblies: R. prolixus (583.9 Mbp, GC 34.0%, N 3.3%) and Triatoma infestans (1.1 Gbp, GC 33.8%, N 2.5%). Furthermore, we also produced the first non-triatomine predatory reduviid whole genome assembly for Platymeris biguttatus (909 Mbp, GC 31.9%, N 0.8%), required for genomic comparisons. All of them present high gene completeness (BUSCOs >90%). The mitogenomes show sizes over 15,900 bp, with mostly conserved gene order of the 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNAs and control region.

Annotated genes related to hematophagy include lipocalins, triabins, odorant binding proteins, ionotropic receptors, and olfactory receptors, among many others. We compare these, focusing on the two main tribes, and the similarities of the non-hematophagous B. herreri and P. biguttatus with each of them. The preliminary results indicate a polyphyletic origin of hematophagy in Triatominae, reopening the debate on this relevant aspect of Chagas disease vector biology, and stressing the need for increasing the genomic resources for this neglected illness.

This work was supported by: Wellcome [204820/Z/16/Z] (AB), Lister/Bellahouston Fellowship (AB); MR/Y001338/1 (MSL); and Agencia Nacional de Investigación y Desarrollo (ANID): Programa Becas - Doctorado Becas Chile 2019 72200391 (AB), FONDECYT 1221045 (CBM), ANILLO-PIC2-ATE230025 (CBM, AB, MSL), and MILENIO-ICN2021_044 (MLA).