Nuclear and Wolbachia-based multimarker approach for the rapid and accurate identification of tsetse species

Abstract

BackgroundTsetse flies (Diptera: Glossinidae) are solely responsible for the transmission of African trypanosomes, causative agents of sleeping sickness in humans and nagana in livestock. Due to the lack of efficient vaccines and the emergence of drug resistance, vector control approaches such as the sterile insect technique (SIT), remain the most effective way to control disease. SIT is a species-specific approach and therefore requires accurate identification of natural pest populations at the species level. However, the presence of morphologically similar species (species complexes and sub-species) in tsetse flies challenges the successful implementation of SIT-based population control.ResultsIn this study, we evaluate different molecular tools that can be applied for the delimitation of different Glossina species using tsetse samples derived from laboratory colonies, natural populations and museum specimens. The use of mitochondrial markers, nuclear markers (including internal transcribed spacer 1 (ITS1) and different microsatellites), and bacterial symbiotic markers (Wolbachia infection status) in combination with relatively inexpensive techniques such as PCR, agarose gel electrophoresis, and to some extent sequencing provided a rapid, cost effective, and accurate identification of several tsetse species.ConclusionsThe effectiveness of SIT benefits from the fine resolution of species limits in nature. The present study supports the quick identification of large samples using simple and cost effective universalized protocols, which can be easily applied by countries/laboratories with limited resources and expertise.Electronic supplementary materialThe online version of this article (10.1186/s12866-018-1295-4) contains supplementary material, which is available to authorized users.

Detecting Wahlund effects together with amplification problems: Cryptic species, null alleles and short allele dominance in Glossina pallidipes populations from Tanzania

“…We amplified partial sequences of ITS1 using primers Glossina_ITS1_for and Glossina_ITS1_rev (Dyer et al, ), following the protocol described in this paper. For G. pallidipes , the ITS1 PCR product should display a length of around 919 bp, while G. brevipalpis and G. swynnertoni are expected to display the G. morsitans profile (~775 bp) (Augustinos et al, ). This was used on a selected subset of G. pallidipes to check for agreement with species determination (see Results).…”

The internal transcribed spacer 1 sequence polymorphism brings updates to tsetse species distribution in the northern Cameroon: Importance in planning efficient vector control

“…These results are consistent with previous studies that reported a misidentification of wild tsetse species (particularly, G. palpalis palpalis , G. palpalis gambiensis , G. tachinoides and G. morsitans submorsitans ). They suggest that the morphological characters alone are not sufficient for accurate identification of tsetse fly species (Augustinos et al, 2018; Dyer et al, 2008). The ITS1 length polymorphism detected on a polyacrylamide gel was enough to differentiate the species studied.…”

“…Although morphological characteristics allowed the classification of 31 tsetse species into three distinct groups, it remains very difficult to clearly distinguish some tsetse species from the same group (Augustinos et al, 2018). For instance, G. palpalis palpalis , G. tachinoides and G. fuscipes not only share identical morphological characteristics but also can be in sympatry in some bio‐ecological settings.…”

“…Molecular tools using a simple PCR have been investigated to help accurate identification of these species. Indeed, the interspecific polymorphism at the internal transcribed spacer‐1 (ITS1) region has proven highly discriminatory for the majority of Glossina taxa from sub‐Saharan Africa (Augustinos et al, 2018; Dyer et al, 2008; Shaida et al, 2018).…”

The Insect Pest Control Laboratory of the Joint FAO/IAEA Programme: Ten Years (2010–2020) of Research and Development, Achievements and Challenges in Support of the Sterile Insect Technique

“…Interestingly, Wolbachia genome sequences were also found in the genome of G. austeni , which also contains an active cytoplasmic Wolbachia infection [ 175 ]. It is worth noting that the presence of chromosomal and cytoplasmic Wolbachia gene sequences together with a nuclear marker (internal transcribed spacer 1, ITS1) allowed us to develop a quick, effective and robust protocol for the accurate identification of several tsetse species and subspecies, irrespectively of their origin (field, laboratory or museum specimens) (accessed on 10 February 2021) [ 176 ].…”