Location: Chemistry Research Unit
Title: Identification of three Halloween genes from the varroa mite and their expression during brood cell invasion Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 18, 2013
Publication Date: N/A
Technical Abstract: Biosynthesis of 20-hydroxyecdysone (20E) in insects involves the action of five cytochrome P450s collectively known as Halloween genes. Transcripts from 3 Halloween genes [spook (Vdspo), disembodied (Vddib) and shade (Vdshd)] from the varroa mite were identified, sequenced and mapped to their genomic sequences. Predicted proteins from the coding regions of Vdspo, Vddib and Vdsh shared 33.3, 32.1 and 29.6% identity with their orthologs from Drosophila melanogaster, respectively. The Vdspo transcript was observed in gut preparations, while Vddib was present in the ovary/lyrate organ and Vdshd was present in ovary/lyrate organ, Malpighian tubules and gut samples. Transcript levels between phoretic mites and early reproductive mites, from pre-capping brood cells, were not significantly different for Vdspo. However, Vddib and Vdshd were significantly up-regulated by 87 and 105%, respectively. A cell invasion assay showed transcript levels from Vdspo, Vddib and Vdshd were not significantly different between mites that entered a brood cell within 4 hr compared to mites that remained on adult bees. These results suggest that the expression of Vddib and Vdshd does not direct the varroa mite cell invasion behavior, but is associated with the physiological shift from phoretic to reproductive state.