Functional Analysis of a Carboxylesterase Gene Associated With Isoprocarb and Cyhalothrin Resistance in Rhopalosiphum padi (L.)

Abstract

Carboxylesterase (CarE) is an important class of detoxification enzymes involved in insecticide resistance. However, the molecular mechanism of CarE-mediated insecticide resistance in Rhopalosiphum padi, a problematic agricultural pest, remains largely unknown. In the present study, an isoprocarb-resistant (IS-R) strain and a cyhalothrin-resistant (CY-R) strain were successively selected from a susceptible (SS) strain of R. padi. The enzyme activity indicated that enhanced carboxylesterase activity contributes to isoprocarb and cyhalothrin resistance. The expression levels of putative CarE genes were examined and compared among IS-R, CY-R, and SS strains, and only the R. padi carboxylesterase gene (RpCarE) was significantly over expressed in both the IS-R and CY-R strains compared to the SS strain. The coding region of the RpCarE gene was cloned and expressed in Escherichia coli. The purified RpCarE protein was able to catalyze the model substrate, α-naphtyl acetate (Kcat = 5.50 s-1; Km = 42.98 μM). HPLC assay showed that the recombinant protein had hydrolase activity against isoprocarb and cyhalothrin. The modeling and docking analyses consistently indicated these two insecticide molecules fit snugly into the catalytic pocket of RpCarE. Taken together, these findings suggest that RpCarE plays an important role in metabolic resistance to carbamates and pyrethroids in R. padi.

Carboxylesterase genes in nitenpyram‐resistant brown planthoppers, Nilaparvata lugens

“…CarE enzymes can be divided into nine clades based on sequence similarity (Ranson et al ., 2002), seven of which are represented in N. lugens . Among these, catalytic activity occurs in a ‐esterase and β ‐esterase, which has been reported to be associated with resistance to organophosphates, pyrethroids and carbamates (Hawkes & Hemingway, 2002; Wei et al ., 2016; Wang et al ., 2018). In N. lugens , 19 CarE genes belong to the β ‐esterase clade, and the significant expansion of genes in this clade suggests a likely increased range of lipid metabolism and xenobiotic detoxification (Hawkes & Hemingway, 2002).…”

Genome-Wide Identification and Functional Analysis of Carboxylesterase and Methylesterase Gene Families in Peach (Prunus persica L. Batsch)

“…In the presence of water, CXEs catalyze the hydrolysis of a carboxylic ester to an alcohol and a carboxylic acid anion. However, compared to the broad ranges of functions established in mammals, insects, and microorganisms (Levisson et al, 2009; Wang et al, 2018; Wang et al, 2019), the biological roles of CXEs in plants are poorly understood. It is known that hydrolysis of natural compounds often alters their biological activity and transport and it has been suggested that CXEs play important roles in plants.…”

Asexual reproduction of a few genotypes favored the invasion of the cereal aphidRhopalosiphum padiin Chile

“…Likewise, the widespread superclone NZ3 of M. persicae on potatoes in New Zealand (Van Toor et al, 2008) has enhanced carboxylesterase activity and kdr and super-kdr mutations that confer resistance to organophosphates and pyrethroids, respectively. Regarding R. padi , insecticide-resistant samples from China have been recently described (Wang et al, 2016, 2018a, 2018c). However, it remains unknown whether these strains correspond to clonal lineages developing as superclones.…”

“…It is projected that densities of R. padi will increase in warmer climates, which favor aphid dispersal and virus transmission (Ryalls & Harrington, 2016; Claflin, Power & Thaler, 2017). In addition, R. padi has evolved both metabolic and target‐site mechanisms of resistance to several synthetic insecticides used for its control (e.g., organophosphates, carbamates, and neonicotinoids), particularly in important areas of wheat production in Asia where this aphid has rapidly become the most frequent cereal pest (Chen et al, 2007; Wang et al, 2018a, 2018c). Therefore, R. padi represents a serious present and future threat to food security.…”