Overexpression of PxαE14 Contributing to Detoxification of Multiple Insecticides in Plutella xylostella (L.)

Abstract

The diamondback moth, Plutella xylostella (L.), has evolved with varying degrees of resistance to almost all major classes of insecticides and has become the most resistant pest worldwide. The multiresistance to different types of insecticides has been frequently reported in P. xylostella, but little is known about the mechanism. In this study, a carboxylesterase (CarE) gene, PxαE14, was found significantly overexpressed in a field-evolved multiresistant P. xylostella population and can be dramatically induced by eight of nine tested insecticides. Results of the real-time quantitative polymerase chain reaction (RT-qPCR) showed that PxαE14 was predominantly expressed in the midgut and malpighian tubule of larvae. Knockdown of PxαE14 dramatically increased the susceptibility of the larvae to β-cypermethrin, bifenthrin, chlorpyrifos, fenvalerate, malathion, and phoxim, while overexpression of PxαE14 in Drosophila melanogaster increased the tolerance of the fruit flies to these insecticides obviously. More importantly, gas chromatography−mass spectrometry (GC−MS) and liquid chromatography−tandem mass spectrometry (LC−MS/MS) assay showed that the recombinant PxαE14 expressed in Escherichia coli exhibited metabolic activity against the six insecticides. The homology modeling, molecular docking, and molecular dynamics simulation analyses showed that these six insecticides could stably bind to PxαE14. Taken together, these results demonstrate that constitutive and inductive overexpression of PxαE14 contributes to detoxification of multiple insecticides involved in multiresistance in P. xylostella. Our findings provide evidence for understanding the molecular mechanisms underlying the multiresistance in insect pests.

Dynamic Roles of Insect Carboxyl/Cholinesterases in Chemical Adaptation

“…More recently, the constitutive and inductive overexpressions of several α-esterases were selected by using forward and reverse genetic approaches in multi-insecticide resistant Plutella xylostella strains [ 102 ]. Further functional studies suggested that the overexpression of one of these esterases, Px αE14, may play roles in resistance to multiple OP and pyrethroid insecticides in P. xylostella [ 103 ].…”

High-Resolution Genetic Mapping Combined with Transcriptome Profiling Reveals That Both Target-Site Resistance and Increased Detoxification Confer Resistance to the Pyrethroid Bifenthrin in the Spider Mite Tetranychus urticae

“…Shi et al (2016) showed that the esterase TCE2 of T. cinnabarinus (Boisduval) was able to degrade the pyrethroid fenpropathrin [ 104 ], while, very recently, it was also shown that an esterase of the fungus gnat, Bradysia odoriphaga , had significant hydrolase activity towards the ester-containing substances bifenthrin and malathion [ 105 ]. Lastly, Li et al reported that two esterases of Plutella xylostella (Pxα14 and PxEST-6) could metabolize bifenthrin and that the RNAi knockdown of Pxα14 caused an increase in resistance to bifenthrin [ 106 , 107 ]. Based on these examples, we selected two CCEs—CCE58, overexpressed in all pairwise comparisons, and CCEinc18, overexpressed in four pairwise differential gene expression analyses—as the top candidates to study their bifenthrin-metabolizing potential.…”

Rapid Detection of Malathion, Phoxim and Thiram on Orange Surfaces Using Ag Nanoparticle Modified PDMS as Surface-Enhanced Raman Spectroscopy Substrate

“…To better protect humans and livestock from the harmful effects of pesticides, it is urgently needed to develop effective analytical methods, especially those that can target mixed pesticides [ 11 ]. So far, malathion, phoxim, and thiram in agricultural products can be accurately measured using high-performance liquid chromatography (HPLC) [ 12 ], gas chromatography tandem mass spectrometry (GC-MS) [ 13 ], and liquid chromatography tandem mass spectrometry (LC-MS) [ 14 ]. However, these techniques require sophisticated and expensive instruments, as well as fully-trained technicians, to operate.…”