Identification of odorant-binding protein genes from antennal expressed sequence tags of the onion fly, Delia antiqua.
Insect odorant-binding proteins (OBPs) are thought to play a crucial role in the chemosensation of hydrophobic molecules such as pheromones and host chemicals. The onion fly, Delia antiqua, is a specialist feeder of Allium plants, and utilizes a host odorant n-dipropyl disulfide as a cue for its oviposition. Because n-dipropyl disulfide is a highly hydrophobic compound, some OBPs might be indispensable for perception of it. However, no OBP gene has been identified in D. antiqua. Here, to obtain the DNA sequences of D. antiqua OBPs, we performed an analysis of antennal expressed sequence tags (ESTs). Among 288 EST clones, eight D. antiqua OBP genes were identified for the first time. Phylogenetic analysis revealed that each D. antiqua OBP gene is more closely related to its Drosophila orthologs than to the other D. antiqua OBP genes, suggesting that these OBP genes had emerged before the divergence of Delia and Drosophila species. All of the eight D. antiqua OBPs are expressed not only in the antennae but also in the legs, suggesting additional roles in the taste perception of non-volatile compounds. These findings serve as an important basis for understanding the molecular mechanisms underlying the host adaptations of D. antiqua.
Mitaka
Hayato
H
Laboratory of Applied Entomology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan.
Matsuo
Takashi
T
Miura
Nami
N
Ishikawa
Yukio
Y
D000818:Animals; D057506:Arthropod Antennae / Q000378:metabolism*; D004175:Diptera / Q000235:genetics*; D004330:Drosophila / Q000235:genetics; D020224:Expressed Sequence Tags; D005786:Gene Expression Regulation; D017344:Genes, Insect / Q000235:genetics*; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D019697:Onions / Q000469:parasitology*; D010802:Phylogeny; D018035:Receptors, Odorant / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D019476:Insect Proteins; D018035:Receptors, Odorant; C045648:odorant-binding protein