Plant Insecticide L-Canavanine Repels Drosophila via the Insect Orphan GPCR DmX
Figure 8
DmXR is localized to GRN dendrites and is dispensable for caffeine sensitivity.
(A) Subcellular localization of the DmX receptor. Anti-HA immunostaining on labellum of Gr66a-GAL4/+;UAS-HAmtt/+ flies. HAmtt is a HA-tagged version of the DmX receptor. When DmXR is expressed in Gr66a-GRNs, it is principally targeted to the dendrite. Note the strong localization of the receptor at the tip of the dendrite (arrowhead). (B) The aversive effect of caffeine is not affected in mtt mutant flies. Behavioral analyses were performed as described in Figure 6 except that 100 mM sucrose (white) and 100 mM sucrose+50 mM caffeine (grey) solutions were used. Histograms show the percentage of PER and PR of control (WT) and mtt mutant (mttf06268/mttf06268) flies. For both control and mtt mutant flies, the caffeine inhibits the sucrose-induced PER. This effect is not complete as some flies still performed a PER in the presence of caffeine. Most of these flies retract their proboscis in response to caffeine, similar to what is observed with l-canavanine. Error bars indicate SEM. Double asterisks indicate significant differences by t-test (p<0.001).