Meeting Abstract
The spiny lobster, P. argus, has two classes of chemosensilla representing “olfaction” and “distributed chemoreception.” Olfactory sensilla are found exclusively on antennular lateral flagella (LF) and are innervated only by olfactory receptor neurons (ORNs) that project into olfactory lobes organized into glomeruli. Distributed chemoreceptor sensilla are found on all body surfaces including LF and leg dactyls, and are innervated by both chemoreceptor (CRNs) and mechanoreceptor neurons that project into somatotopically organized neuropils. Here, we examined the expression of three classes of chemosensory proteins in transcriptomes of the olfactory organ (LF), distributed chemoreception organ (dactyls), and brain of P. argus: Ionotropic Receptors (IRs), which are related to ionotropic glutamate receptors and found in all protostomes including crustaceans; Gustatory Receptors (GRs), which are ionotropic receptors that are abundantly expressed in insects but are more restricted in crustaceans; and Transient Receptor Potential (TRP) channels, a diverse set of sensor-channels that include several families of chemosensors in diverse animals. We identified over 100 IRs, 1 GR, and homologues for most Group 1 TRP channel subfamilies. The number of IRs expressed in the LF is far greater compared to the dactyls. We found co-receptor IRs, IR25a, IR8a, IR76b, and IR93a, and conserved IR, IR40a, in all three tissues. Immunocytochemistry showed that IR25a is expressed in most ORNs, CRNs, and specific cells near the olfactory lobe. While the function of these receptors was not explored, our results suggest an abundant diversity of chemoreceptor proteins. Further analysis will explore the expression of these proteins in additional decapod crustacean species.
