title: General odorant-binding proteins and sex pheromone guide larvae of Plutella xylostella to better food.
abstract: Olfaction of Lepidopteran larvae has received little attention, compared to the damage to crops done by insects at this stage. We report that larvae of the diamondback moth Plutella xylostella are attracted to their natural sex pheromone and to their major component (Z)-11-hexadecenal, but only in a food context. For such task they use two general odorant-binding proteins (GOBPs), abundantly expressed in the three major sensilla basiconica of the larval antenna, as shown by whole-mount immunostaining and immunocytochemistry experiments. None of the three genes encoding pheromone-binding proteins (PBPs) are expressed at this stage. Both recombinant GOBPs bind (Z)-11-hexadecenal and the corresponding alcohol, but not the acetate. Binding experiments performed with five mutants of GOBP2, where aromatic residues in the binding pocket were replaced with leucine showed that only one or two amino acid substitutions can completely abolish binding to the pheromone shifting the affinity to plant-derived compounds. We hypothesise that detection of their species-specific pheromone may direct larvae to the sites of foraging chosen by their mother when laying eggs, to find better food, as well as to reduce competition with individuals of the same or other species sharing the same host plant. We also provide evidence that GOBP2 is a narrowly tuned binding protein, whose affinity can be easily switched from linear pheromones to branched plants terpenoids, representing a tool better suited for the simple olfactory system of larvae, as compared to the more sophisticated organ of adults.
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Ban
authors.affiliation: Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Song
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China. Electronic address: ppelosi.obp@gmail.com.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China. Electronic address: grwang@ippcaas.cn.
authors.forename: Guirong
authors.initials: G
authors.lastname: Wang
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D001070:Appetitive Behavior; D005502:Food; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D008958:Models, Molecular; D009036:Moths / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D018035:Receptors, Odorant / Q000378:metabolism*; D012724:Sex Attractants / Q000378:metabolism*; D012903:Smell
chemical_list: D000447:Aldehydes; D019476:Insect Proteins; D018035:Receptors, Odorant; D012724:Sex Attractants; C045648:odorant-binding protein; C061128:11-hexadecenal
keywords: General odorant-binding protein; Immunocytochemistry; Larvae behaviour; Ligand-binding; Pheromones; Plutella xylostella