Identification and tissue expression profile of genes from three chemoreceptor families in an urban pest, Periplaneta americana.

Periplaneta americana is a notorious urban pest prevalent in human habitats; very little is known about its chemosensory mechanism. Employing the advanced next-generation sequencing technique, in the present study, we conducted transcriptome sequencing and analysis of the antennae of the adult males and females as well as their mouthparts using an Illumina platform. This resulted in the discovery of a huge number of the members of all major known chemosensory receptor families in P. americana, including 96 odorant receptors (ORs), 53 ionotropic receptors (IRs), and 33 gustatory receptors (GRs). Tissue expression profiles showed most of them mainly expressed in antennae and phylogenetic analysis demonstrated the expansion in the clade distinguishing them from other functionally well-known Lepidoptera species. A high percentage of chemosensory receptor genes (ORs in particular) showing female antenna bias in mRNA expression was observed. Our results provide a basis for further investigations on how P. americana coordinates its chemosensory receptor genes in chemical communication with environments, and for development of novel pest management approaches.