title: Transcriptome analysis of the synganglion from the honey bee mite, Varroa destructor and RNAi knockdown of neural peptide targets.
abstract: Varroa mites (Varroa destructor) and the viruses that they transmit are one of the major contributing factors to the global honey bee crisis. Gene products within the nervous system are the targets of all the insecticides currently used to control Varroa but there is a paucity of transcriptomic data available for Varroa neural tissues. A cDNA library from the synganglia ("brains") of adult female Varroa was constructed and 600 ESTs sequenced and analysed revealing several current and potential druggable targets. Contigs coding for the deformed wing virus (DWV) variants V. destructor virus-1 (VDV-1) and the recombinant (VDV-1DVD) were present in the synganglion library. Negative-sense RNA-specific PCR indicated that VDV-1 replicates in the Varroa synganglion and all other tissues tested, but we could not detect DWV replicating in any Varroa tissue. Two neuropeptides were identified in the synganlion EST library: a B-type allatostatin and a member of the crustacean hyperglycaemic hormone (CHH) superfamily. Knockdown of the allatostatin or the CHH-like gene by double-stranded RNA-interference (dsRNAi) resulted in 85% and 55% mortality, respectively, of Varroa. Here, we present the first transcriptomic survey in Varroa and demonstrate that neural genes can be targeted by dsRNAi either for genetic validation of putative targets during drug discovery programmes or as a potential control measure in itself.
authors.affiliation: School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK.
authors.forename: Ewan M
authors.initials: EM
authors.lastname: Campbell
authors.affiliation: National Bee Unit, Fera, Sand Hutton, York YO41 1LZ, UK.
authors.forename: Giles E
authors.initials: GE
authors.lastname: Budge
authors.affiliation: Vita (Europe) Limited, Vita House, London Street, Basingstoke, Hampshire RG21 7PG, UK.
authors.forename: Max
authors.initials: M
authors.lastname: Watkins
authors.affiliation: School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK. Electronic address: a.bowman@abdn.ac.uk.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Bowman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees / Q000469:parasitology*; D018076:DNA, Complementary; D020224:Expressed Sequence Tags; D005260:Female; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000235:genetics*; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D059467:Transcriptome; D057077:Varroidae / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D009479:Neuropeptides
keywords: Allatostatin; Apis mellifera; Crustacean hyperglycaemic hormone; Deformed wing virus; Synganglion; Varroa destructor; gene knockdown