Molecular characterization and expression pattern of an odorant receptor from the myiasis-causing blowfly, Lucilia...

The blowfly Lucilia sericata (Diptera: Calliphoridae) is a facultative ectoparasite that causes myiasis in both man and animals, leading to serious human health problems and economic losses in the livestock industry. Like other insects, olfaction of this species plays an important role in host location and is presumably mediated by a seven transmembrane receptor family. Here, we isolate and characterize LserOR1, which is the first candidate member of the odorant receptor gene family from L. sericata. LserOR1 displayed high amino acid conservation with previously identified Or83b orthologs from different insect species. The transcripts of LserOR1 were detected in the major olfactory organs including the antennae and maxillary palps, as well as in traditionally non-olfactory tissues such as the legs and female ovipositors. In developmental studies, a quantitative real-time PCR assay was developed and validated for determining the relative expression levels of LserOR1 during several stages. In contrast to its extremely high expression in the adult stage, LserOR1 expression was at the lowest level during the egg stage, and then increased to a peak through the first two larval stages before declining in the third-instar stage. These results suggest that a broadly expressed LserOR1 receptor is likely to be essential for olfactory sensory processes throughout the lifetime of L. sericata. The present study provides the information that may aid in the development of novel blowfly repellents using olfactory proteins as molecular targets.