In silico identification and assessment of insecticide target sites in the genome of the small hive beetle, Aethina tumida

Frank D Rinkevich,Lelania Bourgeois

doi:10.1186/s12864-020-6551-y

Frank D Rinkevich, Lelania Bourgeois

Open Access

https://doi.org/10.1186/s12864-020-6551-y

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Abstract

BackgroundThe small hive beetle, Aethina tumida, is a rapidly emerging global pest of honey bee colonies. Small hive beetle infestation can be extremely destructive, which may cause honey bees to abscond and render colony infrastructure unusable. Due to the impacts small hive beetles have on honey bees, a wide variety of physical, cultural, and chemical control measures have been implemented to manage small hive beetle infestations. The use of insecticides to control small hive beetle populations is an emerging management tactic. Currently, very little genomic information exists on insecticide target sites in the small hive beetle. Therefore, the objective of this study is to utilize focused in silico comparative genomics approaches to identify and assess the potential insecticide sensitivity of the major insecticide target sites in the small hive beetle genome.ResultsNo previously described resistance mutations were identified in any orthologs of insecticide target sites. Alternative exon use and A-to-I RNA editing were absent in AtumSC1. The ryanodine receptor in small hive beetle (Atum_Ryr) was highly conserved and no previously described resistance mutations were identified. A total of 12 nAChR subunits were identified with similar alternative exon use in other insects. Alternative exon use and critical structural features of the GABA-gated chloride channel subunits (Atum_RDL, Atum_GRD, and Atum_LCCH3) were conserved. Five splice variants were found for the glutamate-gated chloride channel subunit. Exon 3c of Atum_GluCl may be a beetle-specific alternative exon. The co-occurrence of exons 9a and 9b in the pH-sensitive chloride channel (Atum_pHCl) is a unique combination that introduces sites of post-translational modification. The repertoire and alternative exon use for histamine-gated chloride channels (Atum-HisCl), octopamine (Atum_OctR) and tyramine receptors (Atum_TAR) were conserved.ConclusionsThe recently published small hive beetle genome likely serves as a reference for insecticide-susceptible versions of insecticide target sites. These comparative in silico studies are the first step in discovering targets that can be exploited for small hive beetle-specific control as well as tracking changes in the frequency of resistance alleles as part of a resistance monitoring program. Comparative toxicity alongside honey bees is required to verify these in silico predictions.

Highlights

The small hive beetle, Aethina tumida, is a rapidly emerging global pest of honey bee colonies
The aspartic acid residue in Drosophila Sodium Channel 1 (DSC1) is a threonine (T1924) in AtumSC1, as it is in orthologs in Tribolium (XP_ 015837606.1), honey bee (XP_006572013.1), bumble bee (XP_012173372.1) and carpenter ant (EFN62327.1)
It is unlikely if T1924 in AtumSC1 can modulate insecticide sensitivity or be exploited for speciesspecific control of small hive beetle (SHB)

Summary

Introduction

The small hive beetle, Aethina tumida, is a rapidly emerging global pest of honey bee colonies. The small hive beetle (SHB), Aethina tumida, is a global pest of honey bee colonies that is rapidly expanding its presence outside of its native range in Sub-Saharan Africa to recently reported infestations in Brazil [1] and South Korea [2]. This dynamic worldwide distribution is a consequence of the global trade in beeswax products that are infested with SHB [3]. Colonies of Russian honey bees tend to have fewer SHB than Italian honey bees [11]

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