MOLECULAR CHARACTERIZATION OF TWO CARBOXYLESTERASE GENES OF THE CITRUS RED MITE, Panonychus citri (ACARI: TETRANYCHIDAE)

Abstract

The citrus red mite, Panonychus citri, is known for its ability to rapidly evolve resistance to insecticides/acaricides and to adapt to hosts that produce toxins. To get better insight into the detoxification mechanism of P. citri, two carboxylesterase (CarE) genes, PCE1 and PCE2, were isolated and characterized. PCE1 and PCE2 contained open reading frames of 1,653 and 1,392 nucleotides, encoding proteins of 550 and 463 amino acid residues, respectively. Phylogenetic analyses showed that PCE1 and PCE2 were most closely related to the CarE genes from other phytophagous mites. The transcriptional profiles of two CarE genes among developmental stages (egg, larva, nymph, adult female, and adult male), after exposing to four acaricides (avermectin, azocyclotin, pyridaben, and spirodiclofen) and acid rain were investigated using real-time quantitative PCR (qPCR). The results showed that during development, PCE1 was highly expressed at the egg stage, whereas PCE2 was abundantly expressed at the adult stage of males. The expression levels of PCE1 were highly induced upon exposure to acaricides and acid rain. On the other hand, the expression levels of PCE2 were increased after treatment with avermectin and pyridaben. These results suggest that PCE1 and PCE2 may have distinct roles in different developmental stages and participate in the detoxification of acaricides.

Involvement of Three Esterase Genes from Panonychus citri (McGregor) in Fenpropathrin Resistance

“…Besides PcE1 , isolated from our previously reported transcriptome [27], two novel CarE genes ( PcE7 and PcE9 ) were cloned, respectively. No point mutation occurred among different field strains of P. citri .…”

“…The current bioassay found the synergist TPP dramatically increased the toxicity of fenpropathrin, indicating that CarEs-mediated detoxification was probably an important mechanism of pyrethroid resistance in P. citri . In the current study, besides PcE1 that was identified to participate in the detoxification of acaricides [27], two novel CarE genes ( PcE7 and PcE9 ) were chosen from transcriptome data as the candidate genes based on the qPCR results of their over-expression in fenpropathrin-resistant filed strains of P. citri . The subsequent phylogenetic analysis with CarE genes from T .…”

Exposure to Diflubenzuron Results in an Up-Regulation of a Chitin Synthase 1 Gene in Citrus Red Mite, Panonychus citri (Acari: Tetranychidae)

“…The citrus red mite, Panonychus citri (McGregor), has a worldwide distribution and is an economically important citrus pest that rapidly adapts to hosts and has evolved resistance to acaricides [26–29]. Although biological control has been successful in mite management, chemical control is still the main strategy against this pest in the field.…”

Identification and Characterization of Seven Glutathione S-Transferase Genes from Citrus Red Mite, Panonychus citri (McGregor)

“…There have been some recent studies on detoxification enzymes that might be involved in development of resistance in P. citri , such as two cytochrome P450 genes, CYP4CF1 and CYP4CL2 [22]. Similarly, the results of acaricide challenge experiments showed that CarE genes, PCE1 and PCE2 , may participate in the detoxification of avermectin and pyridaben [23]. By comparing the correlation coefficient of susceptibility of citrus red mite to pyridaben in nine field populations, along with their GST activities, it was suggested that GSTs could possibly be involved in detoxification of pyridaben in several field populations [24].…”