Abstract:  The diamondback moth, Plutella xylostella L., is one of the most destructive pests in cruciferous vegetables (CFV) all over the world and has developed varied resistance to kinds of insecticides, especially the fastest growing resistance to pyrethroids. Deltamethrin is one of the most toxic synthetic pyrethroid pesticides. Our previous research compared the two-dimensional electrophoresis (2-DE) protein profiles between the deltamethrin-sensitive strain (DS) and the deltamethrin-resistant strain (DR) of the diamondback moth at the adult stage, and significant differences had been identified. In this study, 89 protein spots were identified by 2-DE from the 4th instar larvae of P. xylostella, and then 30 out of 89 spots were subjected to matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) analysis and protein database search to test the proteins expressed only in the resistant strain or differentially expressed in two strains. Thus, 10 protein spots were successfully identified with definite identity, properties and function. Real-time quantitative PCR analysis showed that the expression patterns at the mRNA and protein levels were correlated with each other. This study identifies several proteins that are differentially expressed under the deltamethrin stress, and provides a new scientific basis regarding targets and action mechanisms of deltamethrin and for screening of the resistance-related proteins.

Key words: Plutella xylostella, proteomics, two-dimensional electrophoresis (2-DE), mass spectrometry, deltamethrin, resistance