Abstract: We described the identification and characterization of a new cDNA encoding chemosensory protein1 (CSP1) from the antenna of diamondback moth, Plutella xylostella, a species whose CSPs have not been identified to date. We focused our investigation on this olfactory protein family using reverse transcription-polymerase chain reaction strategies. The results showed that the CSP1 gene in diamondback moth, named PxylCSP1 (GenBank accession no. FJ361903), is 405 bp in length and encodes 134 amino acid residues, with six cysteine residues in conserved positions relative to other known CSPs. The predicted N-terminus hydrophobic region contains 19 amino acid residues within the Has-CSP, displaying the characteristic features of a signal peptide. Thus the predicted molecular weight (MW) of the mature protein is 13.56 kD and isoelectric point (pI) is 6.12. The alignment of PxylCSP1 showed high sequence identity (70%-80%) with other full-length sequences of other lepidoteran CSPs from GenBank. RT-PCR analysis revealed that PxylCSP1 was not only expressed in antennae, but also in head, abdomen, wings and legs. The reasult of real-time PCR further indicated that the transcription level of PxylCSP1 depended on the gender, age, mating status and tissues of the tested moths.

Key words: Plutella xylostella, chemsensory proteins, molecular cloning, RT-PCR, real-time PCR