Abstract: 【Aim】 This study aims to identify the chemosensory protein (CSP) genes in the antennal transcriptome of the pea aphid, Acyrthosiphon pisum, and to investigate the binding characteristics of antennae-enriched CSPs of A. pisum with aphid alarm pheromones, sex pheromones and plant volatiles.【Methods】 Based on the antennal transcriptome data of A. pisum, the CSP genes in antennae were identified. The expression profiles of these CSP genes in antennae and different tissues (antennae, stylet, head without antenna and stylet, thorax, abdomen, leg and wing) of A. pisum adults were assayed based on RPKM value and by semiquantitative RT-PCR, respectively. The binding characteristics of these CSPs in antennae with aphid alarm pheromones and sex pheromones, and plant volatiles were assayed by fluorescence competitive binding assay.【Results】 A total of ten CSP genes were identified from the antennal transcriptome of A. pisum adults. The RPKM value and semiquantitative RT-PCR results revealed that ApisCSP2, ApisCSP4 and ApisCSP5 were highly expressed in the antennae of A. pisum adults. The fluorescence competitive binding assays indicated that ApisCSP4 showed strong binding affinities to the main component of aphid alarm pheromone (E)-β-farnesene (EβF), and the minor component (-)-α-pinene, with the K_i values of 2.2±0.8 and 4.9±0.7 μmol/L, respectively. ApisCSP5 exhibited strong binding affinities to the two components of sex pheromones (+)-(4aS, 7S, 7aR)-nepetalactone and (-)-(1R,4aS,7S,7aR)-nepetalactol, with the K_i values of 4.8±0.9 and 2.6±0.6 μmol/L, respectively.【Conclusion】 There are ten CSP genes identified in the antennal transcriptome of A. pisum adults, among which ApisCSP4 and ApisCSP5 may be involved in the transport of aphid alarm pheromones and sex pheromones, respectively.

Key words: Acyrthosiphon pisum, chemosensory protein, tissue expression, fluorescence competitive binding assay, alarm pheromone, sex pheromone