Xiang-Li Xu

Northwest A & F University, Yang-ling-chen, Shaanxi, China

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Publications (3)5.91 Total impact

  • Guang-Wei Li · Yan Zhang · Yi-Ping Li · Jun-Xiang Wu · Xiang-Li Xu ·
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    ABSTRACT: Odorant-binding proteins (OBPs) act in insect olfactory processes. OBPs are expressed in the olfactory organs and serve in binding and transport of hydrophobic odorants through the sensillum lymph to olfactory receptor neurons within the antennal sensilla. In this study, three OBP genes were cloned from the antennal transcriptome database of Grapholita molesta via reverse-transcription PCR. Recombinant GmolOBPs (rGmolOBPs) were expressed in a prokaryotic expression system and enriched via Ni ion affinity chromatography. The binding properties of the three rGmolOBPs to four sex pheromones and 30 host-plant volatiles were investigated in fluorescence ligand-binding assays. The results demonstrated that rGmolOBP8, rGmolOBP11, and rGmolOBP15 exhibited high binding affinities with the major sex pheromone components (E)-8-dodecenyl acetate, (Z)-8-dodecenyl alcohol, and dodecanol. The volatiles emitted from peach and pear, decanal, butyl hexanoate, and α-ocimene, also showed binding affinities to rGmolOBP8 and rGmolOBP11. Hexanal, heptanal, and α-pinene showed strong binding affinities to rGmolOBP15. Results of the electrophysiological recording experiments and previous behavior bioassays indicated that adult insects had strong electroantennogram and behavioral responses toward butyl hexanoate, hexanal, and heptanal. We infer that the GmolOBP8 and GmolOBP11 have dual functions in perception and recognition of host-plant volatiles and sex pheromones, while GmolOBP15 was mainly involved in plant volatile odorants' perception.
    Archives of Insect Biochemistry and Physiology 11/2015; DOI:10.1002/arch.21309 · 1.02 Impact Factor
  • Hao Chen · Xiang-Li Xu · Yi-Ping Li · Jun-Xiang Wu ·
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    ABSTRACT: Grapholita molesta (Busck) is a worldwide insect pest damaging stone and pome fruits. High temperature can significantly affect insects on survival, development, and fecundity. Heat shock protein (Hsp) genes were speculated to possess a pivotal function in response to high temperature stress. In this study, two full-length heat shock protein genes, Gmhsp90 and Gmhsp70, were cloned from G. molesta using rapid amplification of cDNA ends (RACE). The open reading frames of Gmhsp90 and Gmhsp70 obtained were 2148 bp and 1998 bp in length, respectively. Their deduced amino acids showed high homology to Hsp genes of other species. Subsequently, the transcriptional expression of Gmhsp90 and Gmhsp70 in G. molesta adults exposed at various temperatures (26, 29, 32, 35, 38, 41 and 44°C) for 1h and at 41°C for various time duration (0, 15, 30, 45, 60, 75, 90 and 105 min) were investigated via real time quantitative PCR (qPCR). The relative expression levels of Gmhsp90 and Gmhsp70 in G. molesta adults were both up-regulated with the rise of temperature and time duration. In addition, the Gmhsp70 usually showed a higher transcription accumulation than Gmhsp90. Interestingly, Gmhsp90 and Gmhsp70 in female adults could be induced much earlier than that in male, and the effective induction temperature of them in female was also lower than that in male. The distinct expression profiles of Gmhsp90 and Gmhsp70 indicated that Gmhsp90 and Gmhsp70 may play important roles in G. molesta adults responding to the thermal threat, and they have difference on induction between sexes. This article is protected by copyright. All rights reserved.
    Insect Science 09/2013; 21(4). DOI:10.1111/1744-7917.12057 · 2.14 Impact Factor
  • Guo-Hui Zhang · Yi-Ping Li · Xiang-Li Xu · Hao Chen · Jun-Xiang Wu ·
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    ABSTRACT: Two novel general odorant-binding protein (GOBP) cDNAs (GmolGOBP1 and GmolGOBP2) were cloned and characterized from female antennal tissue of the oriental fruit moth, Grapholita molesta. We focused our investigation on this olfactory protein family by using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends-PCR (RACE-PCR). The full-length open reading frames of GmolGOBP1 and GmolGOBP2 were 492 and 483 nucleotides long, which encode 164 and 161 amino acid residue peptides, respectively. Protein signature analyses revealed that they each contained six conserved cysteines with an N-terminal signal sequence of 20 amino acids. The alignment of the two deduced protein sequences with other Lepidoptera GOBPs showed high sequence similarity (70-80%) with other full-length sequences from GenBank. Sequence similarity between the two GOBPs was only 48%, suggesting that the two proteins belong to different classes of lepidopteran GOBPs. RT-PCR analysis revealed that the two GOBP genes were expressed only in antennae of both sexes. Real-time PCR analysis further indicated that the transcript level of GmolGOBP1 was higher in males than in females, whereas the transcript level of GmolGOBP2 was higher in females than in males. Temporally, the two GOBP genes were expressed during the complete photoperiod (15L:9D). The highest transcript levels of GmolGOBP1 in both sexes and GmolGOBP2 in females were detected at the end of photophase and during scotophase. The expression of GmolGOBP2 in males remained at similar levels during the complete photoperiod. Based on these results, the possible physiological functions of GmolGOBPs are discussed.
    Journal of Chemical Ecology 03/2012; 38(4):427-36. DOI:10.1007/s10886-012-0102-1 · 2.75 Impact Factor