title: Expression Divergence of Chemosensory Genes between Drosophila sechellia and Its Sibling Species and Its Implications for Host Shift.
abstract: Drosophila sechellia relies exclusively on the fruits of Morinda citrifolia, which are toxic to most insects, including its sibling species Drosophila melanogaster and Drosophila simulans. Although several odorant binding protein (Obp) genes and olfactory receptor (Or) genes have been suggested to be associated with the D. sechellia host shift, a broad view of how chemosensory genes have contributed to this shift is still lacking. We therefore studied the transcriptomes of antennae, the main organ responsible for detecting food resource and oviposition, of D. sechellia and its two sibling species. We wanted to know whether gene expression, particularly chemosensory genes, has diverged between D. sechellia and its two sibling species. Using a very stringent definition of differential gene expression, we found a higher percentage of chemosensory genes differentially expressed in the D. sechellia lineage (7.8%) than in the D. simulans lineage (5.4%); for upregulated chemosensory genes, the percentages were 8.8% in D. sechellia and 5.2% in D. simulans. Interestingly, Obp50a exhibited the highest upregulation, an approximately 100-fold increase, and Or85c--previously reported to be a larva-specific gene--showed approximately 20-fold upregulation in D. sechellia. Furthermore, Ir84a (ionotropic receptor 84a), which has been proposed to be associated with male courtship behavior, was significantly upregulated in D. sechellia. We also found expression divergence in most of the chemosensory gene families between D. sechellia and the two sibling species. Our observations suggest that the host shift of D. sechellia was associated with the enrichment of differentially expressed, particularly upregulated, chemosensory genes.
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan Research Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Meng-Shin
authors.initials: MS
authors.lastname: Shiao
authors.affiliation: Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain Institute of Human Genetics (IGH), UPR 1142, CNRS, Montpellier, France.
authors.forename: Jia-Ming
authors.initials: JM
authors.lastname: Chang
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan Whole-Genome Research Core Laboratory of Human Diseases, Chang Gung Memorial Hospital, Keelung, Taiwan.
authors.forename: Wen-Lang
authors.initials: WL
authors.lastname: Fan
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Mei-Yeh Jade
authors.initials: MY
authors.lastname: Lu
authors.affiliation: Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain.
authors.forename: Cedric
authors.initials: C
authors.lastname: Notredame
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Shu
authors.initials: S
authors.lastname: Fang
authors.affiliation: Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo, Japan kondo.rumi@ocha.ac.jp whli@sinica.edu.tw.
authors.forename: Rumi
authors.initials: R
authors.lastname: Kondo
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan Department of Ecology and Evolution, University of Chicago kondo.rumi@ocha.ac.jp whli@sinica.edu.tw.
authors.forename: Wen-Hsiung
authors.initials: WH
authors.lastname: Li
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D057506:Arthropod Antennae / Q000737:chemistry / Q000378:metabolism; D001483:Base Sequence; D004330:Drosophila / Q000235:genetics* / Q000378:metabolism*; D029721:Drosophila Proteins / Q000096:biosynthesis* / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D005260:Female; D005638:Fruit; D005786:Gene Expression Regulation; D017344:Genes, Insect; D008297:Male; D008969:Molecular Sequence Data; D032066:Morinda; D018521:Plant Physiological Phenomena; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D018035:Receptors, Odorant / Q000096:biosynthesis* / Q000235:genetics*; D013045:Species Specificity; D059467:Transcriptome
chemical_list: D029721:Drosophila Proteins; D018035:Receptors, Odorant; C045648:odorant-binding protein; D012313:RNA
keywords: Drosophila sechellia; RNA-seq; antennal transcriptome; chemosensory genes; host shift