title: Characterization and functional analysis of a novel glutathione S-transferase gene potentially associated with the abamectin resistance in Panonychus citri (McGregor).
abstract: The citrus red mite, Panonychus citri (McGregor), a major citrus pest distributed worldwide, has been found to be resistant to various insecticides and acaricides used in China. However, the molecular mechanisms associated with the abamectin resistance in this species have not yet been reported. In this study, results showed over-expression of a novel glutathione S-transferases (GSTs) gene (PcGSTm5) in abamectin-resistant P. citri. Quantitative real-time PCR analysis showed that the transcripts of PcGSTm5 were also significantly up-regulated after exposure to abamectin and the maximum mRNA expression level at nymphal stage. The recombinant protein of PcGSTm5-pET-28a produced by Escherichia coli showed a pronounced activity toward the conjugates of 1-chloro-2,4 dinitrobenzene (CDNB) and glutathione (GSH). The kinetics of CDNB and GSH and its optimal pH and thermal stability were also determined. Reverse genetic study through a new method of leaf-mediated dsRNA feeding further support a link between the expression of PcGSTm5 and abamectin resistance. However, no direct evidence was found in metabolism or inhibition assays to confirm the hypothesis that PcGSTm5 can metabolize abamectin. Finally, it is here speculated that PcGSTm5 may play a role in abamectin detoxification through other pathway such as the antioxidant protection.
authors: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, People's Republic of China.
authors: Chong-Yu
authors: CY
authors: Liao
authors: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, People's Republic of China.
authors: Wen-Kai
authors: WK
authors: Xia
authors: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, People's Republic of China.
authors: Ying-Cai
authors: YC
authors: Feng
authors: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, People's Republic of China.
authors: Gang
authors: G
authors: Li
authors: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, People's Republic of China.
authors: Hai
authors: H
authors: Liu
authors: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, People's Republic of China.
authors: Wei
authors: W
authors: Dou
authors: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, People's Republic of China. Electronic address: jjwang7008@yahoo.com.
authors: Jin-Jun
authors: JJ
authors: Wang
mesh_terms: D056810:Acaricides; D000818:Animals; D001681:Biological Assay; D004351:Drug Resistance; D005260:Female; D005796:Genes / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D007559:Ivermectin / Q000031:analogs & derivatives*; D040102:Tetranychidae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*
chemical_list: D056810:Acaricides; C048324:abamectin; D007559:Ivermectin; D005982:Glutathione Transferase
keywords: Abamectin resistance; Glutathione S-transferases; Metabolism assay; Panonychus citri; RNA interference