Biology Reference
In-Depth Information
Table 14.5: (Continued)
Table 14.5: Selected Examples of RNAi Experiments with Arthropods other than
Drosophila
.
Order and species
Traits modified/Method introduced
Reference(s)
Isoptera
Reticulitermes
Caste determination by
hexamerin
/
Injected
Zhou et al. 2006
R. flavipes
Toxicity induced by 2 genes/Feeding
Zhou et al. 2008
Lepidoptera
Epiphyas postvittana
Larval gut carboxylesterase gene,
Pheromone-binding protein, Injected
Turner et al. 2006
Helicoverpa armigera
Cytochrome P450 gene/Fed
Mao et al. 2007
Plutella xylostella
Pheromone production/Injected
Lee et al. 2011
Orthoptera
Gryllus bimaculatus
Analysis of segmentation/Injected
Miyawaki et al. 2004
caudal
+
needed for gnathal and thoracic
patterning/Injected
Shinmyo et al. 2005
Sulfakinin
, a satiety effector/Injected
Meyering-Vos and Muller 2007
Analysis of eye development/Injected
Takagi et al. 2012
RNAi has not been successful in all species tested, and
Garbutt et al. (2012)
suggested that an analysis of the persistence of ds RNA in the hemolymph of
insects could be a predictor of success with RNAi. They showed that ds RNA was
rapidly degraded in
Manduca sexta
, a species that is variably sensitive to RNAi,
but persisted much longer in
Blattella germanica
hemolymph, which is highly
sensitive to RNAi, based on a quantitative reverse-transcription PCR-based assay.
This suggests that rapid degradation of ds RNA by extracellular nucleases may
be one cause of insensitivity to RNAi.
Table 14.5
lists some of the RNAi experiments that have been conducted with
arthropods other than
Drosophila
. RNAi has been successful in diverse species,
ranging from spider mites (
Tetranychus urticae
) and ticks to aphids, honey bees,
termites, cockroaches,
Tribolium
, and Lepidoptera. Delivery of the ds RNA has
been achieved by injection (
Cruz et al. 2006, Martin et al. 2006, Aung et al. 2011
),
feeding ds RNA (
Maori et al. 2009, Walshe et al. 2009, Whyard et al. 2009
,
He
et al. 2011
), feeding
Escherichia coli
expressing ds RNA (
Li et al. 2011
), soaking
(
Lopez-Martinez et al. 2012
), electroporation (
Karim et al. 2010
), or by transmis-
sion from parent to progeny (
Bucher et al. 2006
,
Khila and Grbic 2007, Li et al.
2011
).
Figure 14.1
shows
Tribolium castaneum
adults that have been genetically
modified using RNAi. This species has a systemic response and RNAi is serving as a
method to understand gene function and development in this beetle.
