title: C-terminus Methionene Specifically Involved in Binding Corn Odorants to Odorant Binding Protein4 inMacrocentrus cingulum.
abstract: The soluble carrier proteins, OBPs carry odor components through sensilium lymph to specific receptors within the antennal sensilla to trigger behavioral responses. Herein, McinOBP4 was characterized from theMacrocentrus cingulum, which is the specialist parasitic insect ofOstrinia furnacalisfor better understanding of olfactory recognition mechanism of this wasp. The classical odorant binding protein McinOBP4 showed good binding affinity to corn green leaf volatiles. RT-qPCR results showed that the McinOBP4 was primarily expressed in male and female wasp antennae, with transcripts levels differing by sex. Fluorescence assays indicate that, McinOBP4 binds corn green leaf volatiles including terpenoides and aliphatic alcohols as well as aldehydes with good affinity. We have also conducted series of binding assay with first mutant (M1), which lacked the last 8 residues and a second mutant (M2), with Met119 replaced by Leucine (Leu119). In the acidic conditions, affinity N-phenylnaphthylamine (1-NPN) to McinOBP4 and M1 were substantially decreased, but increase in basic condition with no significant differences. The lack of C-terminus showed reduced affinity to terpenoides and aliphatic alcohols as well as aldehydes compounds of corn odorants. The mutant M2 with Met119 showed significant reduction in binding affinity to tested odorants, it indicating that Met119 forming hydrophobic chain with the odorants functional group to binding. This finding provides detailed insight of chemosensory function of McinOBP4 inM. cingulumand help to develop low release agents that attract of this wasp to improve ecologically-friendly pest management strategy.
authors.affiliation: State Key Laboratory for the Biology of the Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural SciencesBeijing, China; Bangladesh Sugarcrop Research InstitutePabna, Bangladesh.
authors.forename: Tofael
authors.initials: T
authors.lastname: Ahmed
authors.affiliation: State Key Laboratory for the Biology of the Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Tiantao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for the Biology of the Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Zhenying
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Key Laboratory for the Biology of the Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Kanglai
authors.initials: K
authors.lastname: He
authors.affiliation: State Key Laboratory for the Biology of the Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Shuxiong
authors.initials: S
authors.lastname: Bai
keywords: M. cingulum; OBPs; expression patterns; mutagenesis; odorant-protein binding assay