Differential transcription profiles in A edes aegypti detoxification genes after temephos selection

• Published in: Insect molecular biology Vol. 23; no. 2; pp. 199 - 215
• Main Authors: Saavedra‐Rodriguez, K., Strode, C., Flores, A. E., Garcia‐Luna, S., Reyes‐Solis, G., Ranson, H., Hemingway, J., Black, W. C.
• Format: Journal Article
• Language: English
• Published: 01-04-2014
• ISSN: 0962-1075; 1365-2583
• DOI: 10.1111/imb.12073

The mosquito
A
edes aegypti
is the main vector of
D
engue and
Y
ellow
F
ever flaviviruses. The organophosphate insecticide temephos is a larvicide that is used globally to control
A
e. aegypti
populations; many of which have in turn evolved resistance. Target site alteration in the acetylcholine esterase of this species has not being identified. Instead, we tracked changes in transcription of metabolic detoxification genes using the
A
e. aegypti ‘
D
etox
C
hip
’ microarray during five generations of temephos selection. We selected for temephos resistance in three replicates in each of six collections, five from
M
exico, and one from
P
eru. The response to selection was tracked in terms of lethal concentrations. Uniform upregulation was seen in the epsilon class glutathione‐
S
‐transferase (
eGST
) genes in strains from
M
exico prior to laboratory selection, while
eGSTs
in the
I
quitos
P
eru strain became upregulated after five generations of temephos selection. While expression of many carboxyl/cholinesterase esterase (
CCE
) genes increased with selection, no single esterase was consistently upregulated and this same pattern was noted in the cytochrome
P
450
monooxygenase (
CYP
) genes and in other genes involved in reduction or oxidation of xenobiotics. Bioassays using glutathione‐
S
‐transferase (
GST)
,
CCE
and
CYP
inhibitors suggest that various
CCEs
instead of
GSTs
are the main metabolic mechanism conferring resistance to temephos. We show that temephos‐selected strains show no cross resistance to permethrin and that genes associated with temephos selection are largely independent of those selected with permethrin in a previous study.