Functional transcriptome analyses of Drosophila suzukii antennae reveal mating-dependent olfaction plasticity in females.

Insect olfaction modulates basal behaviors and it is often influenced by the physiological condition of each individual such as the reproductive state. Olfactory plasticity can be achieved by modifications at both peripheral and central nervous system levels. Here we performed a genome-wide analysis of the main olfactory organ, the antenna, to investigate how gene expression varies with female mating status in Drosophila suzukii, a destructive and invasive soft fruit pest. We observed a wide mating-induced up-regulation of chemosensory-related genes in females, especially olfactory receptor (Or) genes. We then used a candidate gene approach to define the comprehensive dataset of antenna-expressed chemosensory receptors and binding proteins, which showed many similarities with Drosophila melanogaster. Candidate-gene approach was also used to finely quantify Or differential expression at isoform level, suggesting post-mating transcriptional modulation of genes involved in the peripheral olfactory system. We identified 27 up-regulated Or transcripts encoded by 25 genes, seven of them were duplications specific to D. suzukii lineage. Post-mating olfactory modulation was further supported by electroantennogram recordings that showed a differential response according to mating status to one out of eight odors tested (isoamyl-acetate). Our study characterizes the transcriptional mechanisms driven by mating in D. suzukii antennae. Understanding the role of genes differentially expressed in virgin or mated females will be crucial to better understand host finding and the crop-damaging oviposition behavior of this species.