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Three H alloween genes from the V arroa mite, V arroa destructor ( A nderson & T rueman) and their expression during reproduction
Author(s) -
Cabrera A. R.,
Shirk P. D.,
Evans J. D.,
Hung K.,
Sims J.,
Alborn H.,
Teal P. E. A.
Publication year - 2015
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/imb.12155
Subject(s) - biology , gene , varroa , vitellogenin , genetics , mite , brood , insect , varroa destructor , ovary , zoology , botany
The ecdysteroid biosynthetic pathway involves sequential enzymatic hydroxylations by a group of enzymes collectively known as H alloween gene proteins. Complete sequences for three H alloween genes, spook ( V d spo), disembodied ( V d dib) and shade ( V d shd), were identified in varroa mites and sequenced. Phylogenetic analyses of predicted amino acid sequences for H alloween orthologues showed that the acarine orthologues were distantly associated with insect and crustacean clades indicating that acarine genes had more ancestral characters. The lack of orthologues or pseudogenes for remaining genes suggests these pathway elements had not evolved in ancestral arthropods. V d spo transcript levels were highest in gut tissues, while V d dib transcript levels were highest in ovary‐lyrate organs. In contrast, V d shd transcript levels were lower overall but present in both gut and ovary‐lyrate organs. All three transcripts were present in eggs removed from gravid female mites. A brood cell invasion assay was developed for acquiring synchronously staged mites. Mites within 4 h of entering a brood cell had transcript levels of all three that were not significantly different from mites on adult bees. These analyses suggest that varroa mites may be capable of modifying 7‐dehydro‐cholesterol precursor and hydroxylations of other steroid precursors, but whether the mites directly produce ecdysteroid precursors and products remains undetermined.