Identification of responsive proteins in Panonychus citri exposed to abamectin by a proteomic approach.

Abamectin is a microbial-derived pesticide widely used for control of agricultural pests. However, sustained use of abamectin has led to the development of resistance in some target species. Previous studies on arthropod resistance to abamectin have mainly used traditional biochemical and molecular approaches. To understand the responses of citrus red mite, Panonychus citri, exposed to abamectin, comparative proteomic analysis was conducted using two-dimensional electrophoresis (2-DE). A total of 26 distinct protein spots were present in response to abamectin exposure. Tandem mass spectrometry (MS/MS) identified 16 proteins that were mainly involved in energy metabolism and detoxification. Some remaining proteins were not identifiable, suggesting that they may be novel. The expression levels of transcripts associated with proteins were analyzed by quantitative reverse transcription PCR (qRT-PCR). Furthermore, to validate the proteomic data obtained in the present study, Western-blot experiment was performed and the expression of sHsp and PcE1 proteins were confirmed, respectively.

BIOLOGICAL SIGNIFICANCE: The citrus red mite has developed resistance to many acaricides, including abamectin. In the current study, we used the proteomic approaches involving 2-DE, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), and MS/MS to document changes in adult P. citri during 24h of abamectin exposure. Abamectin stress induced a total of 16 differentially regulated proteins. The proteomic results were validated in mRNA expression patterns using qRT-PCR. This is the first analysis of differentially expressed proteins in P. citri exposed to abamectin. The results help clarify the physiological mechanisms of P. citri responses to abamectin exposure.