title: Odorant-binding protein (OBP) genes affect host specificity in a fig-pollinator mutualistic system.
abstract: The interaction between figs and their pollinating wasps is regarded as a model system for studying specialized co-evolved mutualism. Chemoreception of fig wasps plays an important role in this interaction, and odorant-binding proteins (OBP) function in the first step of odorant detection. The OBP repertoire of the fig wasp Ceratosolen solmsi is reported to be one of the smallest among insects; however, it is unknown how these OBPs are related to the complicated mating process occurring within the fig cavity and the extreme host specificity of the species. In the present study, we combined a structural analysis of the conserved cysteine pattern and motif order, a phylogenetic analysis, and previous studies on ligand-binding assays to deduce the function of OBPs. We also quantified the expression of OBP genes in different life stages of female and male fig wasps by using real-time quantitative PCR, which can help to predict the function of these genes. The results indicated that CsolOBP1 and CsolOBP2 (or CsolOBP5) in males may bind to pheromones and play important roles in mate choice, whereas CsolOBP4 and CsolOBP5 may primarily function in host localization by females through binding of volatile compounds emitted by receptive figs.
authors.affiliation: College of Plant Protection, Shandong Agricultural University, Tai'an, China.
authors.forename: N
authors.initials: N
authors.lastname: Wang
authors.forename: N X
authors.initials: NX
authors.lastname: Wang
authors.forename: L M
authors.initials: LM
authors.lastname: Niu
authors.forename: S N
authors.initials: SN
authors.lastname: Bian
authors.forename: J H
authors.initials: JH
authors.lastname: Xiao
authors.forename: D W
authors.initials: DW
authors.lastname: Huang
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D030681:Ficus / Q000502:physiology*; D005786:Gene Expression Regulation; D058507:Host Specificity; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D054817:Pollination; D060888:Real-Time Polymerase Chain Reaction; D018035:Receptors, Odorant / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D013559:Symbiosis; D014863:Wasps / Q000235:genetics / Q000502:physiology*
chemical_list: D019476:Insect Proteins; D018035:Receptors, Odorant; C045648:odorant-binding protein
keywords: fig wasps; habitat; predicting function