PT  - JOURNAL ARTICLE
AU  - Youngseok Lee
AU  - Min Jung Kang
AU  - Jaewon Shim
AU  - Chae Uk Cheong
AU  - Seok Jun Moon
AU  - Craig Montell
TI  - Gustatory Receptors Required for Avoiding the Insecticide <span class="sc">l</span>-Canavanine
AID  - 10.1523/JNEUROSCI.4630-11.2012
DP  - 2012 Jan 25
TA  - The Journal of Neuroscience
PG  - 1429--1435
VI  - 32
IP  - 4
4099  - http://www.jneurosci.org/content/32/4/1429.short
4100  - http://www.jneurosci.org/content/32/4/1429.full
SO  - J. Neurosci.2012 Jan 25; 32
AB  - Insect survival depends on contact chemosensation to sense and avoid consuming plant-derived insecticides, such as l-canavanine. Members of a family of ∼60 gustatory receptors (GRs) comprise the main peripheral receptors responsible for taste sensation in Drosophila. However, the roles of most Drosophila GRs are unknown. In addition to GRs, a G protein-coupled receptor, DmXR, has been reported to be required for detecting l-canavanine. Here, we showed that GRs are essential for responding to l-canavanine and that flies missing DmXR displayed normal l-canavanine avoidance and l-canavanine-evoked action potentials. Mutations disrupting either Gr8a or Gr66a resulted in an inability to detect l-canavanine. We found that l-canavanine stimulated action potentials in S-type sensilla, which were where Gr8a and Gr66a were both expressed, but not in Gr66a-expressing sensilla that did not express Gr8a. l-canavanine-induced action potentials were also abolished in the Gr8a and Gr66a mutant animals. Gr8a was narrowly required for responding to l-canavanine, in contrast to Gr66a, which was broadly required for responding to other noxious tastants. Our data suggest that GR8a and GR66a are subunits of an l-canavanine receptor and that GR8a contributes to the specificity for l-canavanine.