title: Identification of Host-Plant Volatiles and Characterization of Two Novel General Odorant-Binding Proteins from the Legume Pod Borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae).
abstract: Chemoreception is a key feature in selection of host plant by phytophagous insects, and odorant-binding proteins (OBPs) are involved in chemical communication of both insects and vertebrates. The legume pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae) is one of the key pest species of cowpea and widely distributed throughout tropical and subtropical regions, causing up to 80% of yield loss. In this study, we investigated the electrophysiological responses of female M. vitrata to floral volatiles from V. unguiculata. Seventeen electroantennogram-active compounds were identified from floral volatiles of V. unguiculata by coupled gas chromatography-electroantennography (GC-EAD) and gas chromatography-mass spectrometry (GC-MS). Then, we cloned two novel full-length GOBP genes (MvitGOBP1 and MvitGOBP2) from the antennae of M. vitrata using reverse transcription PCR. Protein sequence analysis indicated that they shared high sequence similarity with other Pyralididae insect GOBPs and had the typical six-cysteine signature. Real-time PCR analysis indicated that MvitGOBP1-2 mRNA was highly expressed in the antennae of female adult with several thousands-fold difference compare to other tissue. Next, the recombinant MvitGOBP1-2 was expressed in Escherichia coli and purified using Ni ion affinity chromatography. Fluorescence binding assays demonstrated that MvitGOBP1-2 had different binding affinities with 17 volatile odorant molecules including butanoic acid butyl ester, limonene, 4-ethylpropiophenone, 1H-indol-4-ol, butanoic acid octyl ester and 2-methyl-3-phenylpropanal. In the field trapping experiment, these six floral volatiles could effectively attract female moths and showed significant difference compared with the blank lure. These results suggested that MvitGOBPs and the seventeen floral volatiles are likely to function in the olfactory behavior response of female moths, which may have played crucial roles in the selection of oviposition sites. The six compounds that we have identified from the volatiles of V. unguiculata may provide useful information for exploring efficiency monitoring and integrated pest management strategies of this legume pod borer in the field.
authors.affiliation: Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Insect Resource Utilization & Sustainable Pest Management of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore.
authors.forename: Shichang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore.
authors.forename: Daiqin
authors.initials: D
authors.lastname: Li
authors.affiliation: Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
authors.forename: Kaiyu
authors.initials: K
authors.lastname: Liu
authors.affiliation: Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
authors.forename: Guoxiu
authors.initials: G
authors.lastname: Wang
authors.affiliation: Key Laboratory of Insect Resource Utilization & Sustainable Pest Management of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Wang
authors.affiliation: Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ai
mesh_terms: D000818:Animals; D057506:Arthropod Antennae / Q000378:metabolism; D003001:Cloning, Molecular / Q000379:methods*; D007887:Fabaceae / Q000737:chemistry* / Q000469:parasitology; D005260:Female; D054884:Host-Pathogen Interactions; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics / Q000502:physiology*; D009928:Organ Specificity; D010936:Plant Extracts / Q000032:analysis / Q000494:pharmacology; D011485:Protein Binding; D018035:Receptors, Odorant / Q000235:genetics* / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D019476:Insect Proteins; D010936:Plant Extracts; D018035:Receptors, Odorant; D055549:Volatile Organic Compounds; C045648:odorant-binding protein