title: Two odorant-binding proteins mediate the behavioural response of aphids to the alarm pheromone (E)-ß-farnesene and structural analogues.
abstract: BACKGROUND
  Aphids are agricultural pests of great economical interest. Alternatives to insecticides, using semiochemicals, are of difficult applications. In fact, sex pheromones are of little use as aphids reproduce partenogenetically most of the time. Besides, the alarm pheromone, (E)-ß-farnesene for a great number of species, is difficult to synthesize and unstable in the environment. The search for novel semiochemicals to be used in population control can be efficiently approached through the study of the olfactory system at the biochemical level. Recently odorant-binding proteins (OBPs) have been shown to play a central role in olfactory recognition, thus becoming the target of choice for designing new semiochemicals.
  
  
  RESULTS
  To address the question of how the alarm message is recognised at the level of OBPs, we have tested 29 compounds, including (E)-ß-farnesene, in binding assays with 6 recombinant proteins and in behaviour experiments. We have found that good repellents bind OBP3 and/or OBP7, while non repellents present different spectra of binding. These results have been verified with two species of aphids, Acyrthosiphon pisum and Myzus persicae, both using (E)-ß-farnesene as the alarm pheromone.
  
  
  CONCLUSIONS
  Our results represent further support to the idea (so far convincingly demonstrated only in Drosophila) that OBPs are involved in decoding the chemical information of odorants and pheromones, and for the first time provide such evidence in other insect species and using wild-type insects. Moreover, the data offer guidelines and protocols for the discovery of potential alarm pheromones, using ligand-binding assays as a preliminary screening before subjecting selected compounds to behaviour tests.
authors.affiliation: Dipartimento di Biologia delle Piante Agrarie, Pisa, Italy.
authors.forename: Yu Feng
authors.initials: YF
authors.lastname: Sun
authors.forename: Filomena
authors.initials: F
authors.lastname: De Biasio
authors.forename: Hui Li
authors.initials: HL
authors.lastname: Qiao
authors.forename: Immacolata
authors.initials: I
authors.lastname: Iovinella
authors.forename: Shao Xiang
authors.initials: SX
authors.lastname: Yang
authors.forename: Yun
authors.initials: Y
authors.lastname: Ling
authors.forename: Lea
authors.initials: L
authors.lastname: Riviello
authors.forename: Donatella
authors.initials: D
authors.lastname: Battaglia
authors.forename: Patrizia
authors.initials: P
authors.lastname: Falabella
authors.forename: Xin Ling
authors.initials: XL
authors.lastname: Yang
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids / Q000502:physiology*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004924:Escape Reaction / Q000502:physiology*; D005453:Fluorescence; D007300:Insect Control / Q000379:methods*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D055696:Olfactory Perception / Q000502:physiology*; D016133:Polymerase Chain Reaction; D018035:Receptors, Odorant / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012717:Sesquiterpenes / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D018035:Receptors, Odorant; D011994:Recombinant Proteins; D012717:Sesquiterpenes; C045648:odorant-binding protein; C062671:beta-farnesene