Rapid Identification of Tropilaelaps Mite (Mesostigmata: Laelapidae) Species Using a COI Barcode-HRM

Abstract

Tropilaelaps mite (Mesostigmata: Laelapidae) is an ectoparasite of bees present, to date, only on the Asian continent. In the context of the threat of Tropilaelaps's introduction into new regions, accurate, rapid, and sensitive detection of the Tropilaelaps spp. is essential. In the present study, we developed a novel molecular method for bee mite's identification, which consists of a new real-time PCR method. A high-resolution melting analysis (HRM) was then performed on the amplified products to differentiate the species. PCR amplification was applied on the cytochrome c oxidase subunit I gene (580 bp). Short fragments from the most variable regions of this gene were identified in silico to amplify and discriminate among the four Tropilaelaps species. Four reference plasmids were synthesized to characterize species by well-distinguished melting curves. The method was then validated in terms of its specificity and sensitivity using a panel of 12 specimens. The results showed that an HRM method can be applied for the intended objective: for rapid and simultaneous identification of Tropilaelaps species. To our knowledge, this study reports the first direct HRM assay developed for the genome of a bee mite, specific for Tropilaelaps species. This COI barcode-HRM technique could be a promising tool for mite species identification.

Keywords: Tropilaelaps; HRM; mtCOI gene; real-time PCR.