title: Mannose-binding lectin from yam (Dioscorea batatas) tubers with insecticidal properties against Helicoverpa armigera (Lepidoptera: Noctuidae).
abstract: The amino acid sequence of mannose-binding lectin, named DB1, from the yam (Dioscorea batatas, synonym Dioscorea polystachya) tubers was determined. The lectin was composed of two isoforms DB1(Cys86) and DB1(Leu86) consisting of 108 amino acid residues with 90% sequence homology between them. DB1 showed a high sequence similarity to snowdrop (Galanthus nivalis) bulb lectin, GNA; especially, the carbohydrate-binding sites of GNA were highly conserved in DB1. DB1 interacted with D-mannose residues of oligosaccharides, and the oligosaccharides carrying two mannose-alpha-1,3-D-mannose units showed high binding affinity. DB1 was examined for insecticidal activity against Helicoverpa armigera (Lepidoptera: Noctuidae) larvae at different stages of development. The rate of adults successfully emerging from pupae fed on DB1 was 33%, when incorporated into an artificial diet at a level of 0.01% (w/w). Although DB1 had no or marginal inhibitory effects on gut proteolytic and glycolic enzymes, the lectin strongly bound to larval brush border and peritrophic membrane detected by immunostaining. The results show that DB1 may fulfill a defense role against insect pests.
authors.affiliation: Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 981-8555, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ohizumi
authors.forename: Mariam
authors.initials: M
authors.lastname: Gaidamashvili
authors.forename: Shyuichi
authors.initials: S
authors.lastname: Ohwada
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Matsuda
authors.forename: Junko
authors.initials: J
authors.lastname: Kominami
authors.forename: Sachiko
authors.initials: S
authors.lastname: Nakamura-Tsuruta
authors.forename: Jun
authors.initials: J
authors.lastname: Hirabayashi
authors.forename: Takako
authors.initials: T
authors.lastname: Naganuma
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Ogawa
authors.forename: Koji
authors.initials: K
authors.lastname: Muramoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D018076:DNA, Complementary / Q000737:chemistry; D027742:Dioscorea / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry / Q000378:metabolism; D007814:Larva / Q000254:growth & development / Q000378:metabolism; D007915:Lepidoptera / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D037601:Mannose-Binding Lectin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000378:metabolism; D035281:Plant Tubers / Q000737:chemistry*
chemical_list: D018076:DNA, Complementary; D007306:Insecticides; D037601:Mannose-Binding Lectin; D009844:Oligosaccharides