Characterization of Esterase Genes Involving Malathion Detoxification and Establishment of an RNA Interference Method in Liposcelis bostrychophila

Abstract

Esterases (ESTs) play important roles in metabolizing various physiologically endogenous and exogenous compounds, and various environmental xenobiotics in insects. The psocid, Liposcelis bostrychophila is a major pest of stored products worldwide and rapidly develops resistance to commonly insecticides. However, the involvement of ESTs in insecticide metabolization and the application of RNAi approach in psocids have not been well elucidated. In this study, we characterized four LbEST genes and investigated the transcriptional levels of these genes at different developmental stages and under different insecticides exposures to assess their potential roles in response to insecticides. The four LbESTs contain a catalytic triad (Ser-His-Glu) linked to an oxyanion hole and acyl pocket involved in substrate stabilization during its hydrolysis. Synergism observed with the esterase-inhibitor DEF suggests the involvement of esterases in malathion detoxification. LbESTs were expressed during the whole of developmental stages, but predominant abundance in the first nymphal instar and adult stage. The mRNA level of three LbEST genes (except for LbEST4) was induced (1.29-to 5.60 fold) in response to malathion or deltamethrin exposures, indicating that these esterases are involved in the detoxification process. Silencing of LbEST1, LbEST2 or LbEST3 through dsRNA feeding led to a higher mortality of psocids upon the malathion treatment compared to controls (1.83 to 2.69-fold), demonstrating that these esterase genes play roles in malathion detoxification in L. bostrychophila. Our study provides new evidence for understanding of the function and regulation mechanism of esterases in L. bostrychophila in insecticide detoxification. The current study also suggests that the present RNAi method could be applied for gene functional studies in psocids.

A chromosome-level genome of the booklouse, Liposcelis brunnea, provides insight into louse evolution and environmental stress adaptation

“…A high level of resistance to phosphine has been observed in booklice, particularly during the egg stage, which significantly increases both the economic cost of treatments and environmental pollution [ 18 , 19 ]. Several gene families have been proven to be related to the high insecticide resistance of booklice, including esterases (ESTs) [ 20 ], glutathione S-transferase (GST) [ 21 ], and the cytochrome P450 monooxygenases (P450) [ 22 ]. These studies were mainly based on transcriptomic analyses and lacked whole-genome data.…”

Involvement ofMethoprene‐tolerantandKrüppel homolog 1in juvenile hormone‐mediated vitellogenesis of femaleLiposcelis entomophila(End.) (Psocoptera: Liposcelididae)

“…The RNAi bioassay comprised a treatment group ( dsLeMet ‐fed or dsLeKrh1 ‐fed) and a control group ( dsGFP ‐fed). RNAi was performed as described (S. Y. Miao et al, 2021 ; Wei et al, 2020 ) and was further optimized as follows: (1) For each group, dsRNA dissolved in 200 μl of nuclease‐free water was added to a glass bottle (25 ml) containing 10 mg of sieved artificial diet. The final concentration of dsRNAs was 200 μg per mg of artificial diet.…”

“…RNAi was performed as described (S. Y. Miao et al, 2021;Wei et al, 2020) and was further optimized as follows:…”

Enzymes, Reacting with Organophosphorus Compounds as Detoxifiers: Diversity and Functions

“…Thus, most researchers concentrate their efforts on genetic modification of the microenvironment of His and other amino acid residues. However, this artificial progress is now rather modest [ 78 ], and natural evolving is much more creative [ 79 , 80 ] ( Figure 17 ).…”