title: Identification of pheromone components and their binding affinity to the odorant binding protein CcapOBP83a-2 of the Mediterranean fruit fly, Ceratitis capitata.
abstract: The Mediterranean fruit fly (or medfly), Ceratitis capitata (Wiedemann; Diptera: Tephritidae), is a serious pest of agriculture worldwide, displaying a very wide larval host range with more than 250 different species of fruit and vegetables. Olfaction plays a key role in the invasive potential of this species. Unfortunately, the pheromone communication system of the medfly is complex and still not well established. In this study, we report the isolation of chemicals emitted by sexually mature individuals during the "calling" period and the electrophysiological responses that these compounds elicit on the antennae of male and female flies. Fifteen compounds with electrophysiological activity were isolated and identified in male emissions by gas chromatography coupled to electroantennography (GC-EAG). Within the group of 15 identified compounds, 11 elicited a response in antennae of both sexes, whilst 4 elicited a response only in female antennae. The binding affinity of these compounds, plus 4 additional compounds known to be behaviourally active from other studies, was measured using C. capitata OBP, CcapOBP83a-2. This OBP has a high homology to Drosophila melanogaster OBPs OS-E and OS-F, which are associated with trichoid sensilla and co-expressed with the well-studied Drosophila pheromone binding protein LUSH. The results provide evidence of involvement of CcapOBP83a-2 in the medfly's odorant perception and its wider specificity for (E,E)-α-farnesene, one of the five major compounds in medfly male pheromone emission. This represents the first step in the clarification of the C. capitata and pheromone reception pathway, and a starting point for further studies aimed towards the creation of new powerful attractants or repellents applicable in the actual control strategies.
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts. AL5 2JQ, United Kingdom; Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 9, 27100 Pavia, Italia.
authors.forename: P
authors.initials: P
authors.lastname: Siciliano
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts. AL5 2JQ, United Kingdom.
authors.forename: X L
authors.initials: XL
authors.lastname: He
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts. AL5 2JQ, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Woodcock
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts. AL5 2JQ, United Kingdom.
authors.forename: J A
authors.initials: JA
authors.lastname: Pickett
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts. AL5 2JQ, United Kingdom.
authors.forename: L M
authors.initials: LM
authors.lastname: Field
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts. AL5 2JQ, United Kingdom.
authors.forename: M A
authors.initials: MA
authors.lastname: Birkett
authors.affiliation: Institute of Organic Chemistry and Biochemistry of the AS CR, v.v.i., Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic.
authors.forename: B
authors.initials: B
authors.lastname: Kalinova
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 9, 27100 Pavia, Italia.
authors.forename: L M
authors.initials: LM
authors.lastname: Gomulski
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 9, 27100 Pavia, Italia.
authors.forename: F
authors.initials: F
authors.lastname: Scolari
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 9, 27100 Pavia, Italia.
authors.forename: G
authors.initials: G
authors.lastname: Gasperi
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 9, 27100 Pavia, Italia.
authors.forename: A R
authors.initials: AR
authors.lastname: Malacrida
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts. AL5 2JQ, United Kingdom. Electronic address: jing-jiang.zhou@rothamsted.ac.uk.
authors.forename: J J
authors.initials: JJ
authors.lastname: Zhou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057506:Arthropod Antennae; D033622:Ceratitis capitata / Q000378:metabolism / Q000502:physiology*; D055724:Electrophysiological Phenomena; D005260:Female; D008297:Male; D010675:Pheromones / Q000302:isolation & purification / Q000502:physiology*; D010802:Phylogeny; D018035:Receptors, Odorant / Q000502:physiology*; D012737:Sex Factors; D012903:Smell / Q000502:physiology
chemical_list: D010675:Pheromones; D018035:Receptors, Odorant; C045648:odorant-binding protein
keywords: Binding studies; Ceratitis capitata; Electroantennography; Fluorescence displacement; GC–EAG; Medfly; Odorant binding protein; Olfaction; Pheromone; Pheromone binding protein; Protein expression