PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
·
2019
·
IF 2.87
Jiang Zhu,Kai Tian,Christopher A. Reilly,Xinghui Qiu
Helicoverpa armigera and H. assulta are two of the few insects that can feed on hot pepper fruits. Capsaicin and dihydrocapsaicin ( i.e. , capsaicinoids) are the principal pungent compounds in hot peppers. To explore possible molecular mechanisms of adaptation that allow these two species to consume capsaicinoids, the capacity of the three detoxification tissues (fat body, midgut, and Malpighian tubule) of the two pests, to metabolically degrade capsaicin and dihydrocapsaicin, was compared. The results showed that capsaicin and dihydrocapsaicin were metabolized by crude enzyme preparations from all three tissues of the two pests. Five metabolites of capsaicin, and five metabolites of dihydrocapsaicin were identified. Tissue and species differences in the degree of capsaicin and dihydrocapsaicin metabolism were observed. The specialist H. assulta had an overall greater capacity to degrade the capsaicinoids compared to the generalist H. armigera. Further, the midgut was the most significant contributor to capsaicinoid metabolism. The notably high specific activity in Malpighian tubules of H. armigera also further highlights the significance of this organ in xenobiotic detoxification. Alkyl hydroxylation and dehydrogenation were the main pathways for the oxidative biotransformation of both capsaicin and dihydrocapsaicin by cytochrome P450s. This study provides evidence that enhanced metabolic decomposition of capsaicinoids may be an adaptation explaining dietary preferences for Capsicum fruits by these two pests.
研究领域:
昆虫学
·
植物化学
·
分子生物学
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PubMed
高影响因子
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
·
2019
·
IF 2.87
Kai Tian,Jiang Zhu,Mei Li,Xinghui Qiu
Capsaicin (8-methyl- N -vanillyl-6-nonenamide) is the most abundant capsaicinoids found in hot peppers ( Capsicum annum and Capsicum frutescens ). It has been well documented that capsaicin plays an important role in the defense against the attack of herbivores or pathogens on Capsicum plants. A few insect herbivores such as Helicoverpa armigera and Helicoverpa assulta have been recorded to be capable of feeding on hot pepper fruits, suggesting that these insects evolve mechanisms against the toxicity of capsaicin. Although cytochrome P450-meidated detoxification is considered to be an important mechanism by which cotton bollworms cope with capsaicin, experimental evidence is lacking. In this study, we compared the capacity of four H. armigera P450s (CYP6B6, CYP9A12, CYP9A14 and CYP9A17) in capsaicin metabolism, and the capsaicin metabolites were screened and tentatively identified by liquid chromatography–tandem mass spectrometry (LC–MS/MS). HPLC analyses showed that depletion rates of capsaicin were 21.9 ± 0.1, 11.9 ± 1.5, 16.3 ± 1.4 and 14.8 ± 0.2 min −1 for CYP6B6, CYP9A12, CYP9A14 and CYP9A17 respectively. The transformation of capsaicin was inhibited by the P450 inhibitor piperonyl butoxide . A total of seven products were detected, and hydroxylation (aromatic and aliphatic) and dehydrogenation were found to be two main pathways in capsaicin metabolism. In addition, capsaicin metabolism was enzyme selective: M1 (ω-hydroxylated N-macrocyclic metabolite) and M3 (ω-hydroxylated metabolite) were uniquely detected in the CYP6B6 catalytic reaction, while M4 (ω-n hydroxylated capsaicin), M5 (diene of capsaicin) and M6 (doubly oxidized metabolite of dehydrogenated capsaicin) were only detectable in CYP9A metabolisms. A capsaicin dimer (5, 5′-dicapsaicin) was found to be the major metabolite of CYP9A reactions, but the minor product produced by CYP6B6. An overall more similar behavior in capsaicin metabolism was observed among CYP9As than between CYP6B6 and CYP9As. Our data demonstrate that CYP6B6 and CYP9As have a potent capability to transform capsaicin, and individual P450 produce unique metabolite profile. These findings help us to understand the molecular basis of capsaicin adaptation in H. armigera .
研究领域:
昆虫学
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植物化学
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分子生物学
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PubMed
高影响因子
CURRENT BIOLOGY
·
2023
·
IF 9.2
Xiaxuan Zhang,Yang Liu,Mengbo Guo,Dongdong Sun,Mengjun Zhang,Xi Chu,Bente Gunnveig Berg,Guirong Wang
Finding ideal oviposition sites is a task of vital importance for all female insects. To ensure optimal conditions for their progeny, females of herbivorous insects detect not only the odors of a relevant host plant but also chemicals released by eggs, named oviposition-deterring pheromones (ODPs). It is reported that such chemicals play critical roles in suppressing female oviposition behavior; however, the molecular mechanism underlying the detection of egg-derived ODPs remains elusive. Here, we have identified three specific fatty acid methyl esters from the surface of eggs of Helicoverpa armigera serving as ODPs—methyl oleate (C18:1ME), methyl palmitate (C16:0ME), and methyl stearate (C18:0ME). We demonstrated that these ODPs are detected by the receptor, HarmOR56 , exclusively expressed in sensilla trichodea on female antennae. To assess the significance of this receptor, we disrupted HarmOR56 in H. armigera using CRISPR-Cas9 and found that mutant females did not respond to the ODPs, neither in behavioral nor in electrophysiological tests. We therefore conclude that HarmOR56 is indispensable for identifying the ODPs. This study explores, for the first time, how a female-specific odorant receptor detects chemicals from conspecific eggs. Our data elucidate the intriguing biological phenomenon of repulsion to conspecific eggs during oviposition and contribute new insight into a female-specific olfactory pathway linked to reproduction.
研究领域:
昆虫学
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分子生物学
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化学生态学
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高影响因子
INSECT MOLECULAR BIOLOGY
·
2018
·Vol. 28
·期 1
·23-34
·
IF 2.492
Y.-L. Sun,J.-F. Dong,C. Ning,P.-P. Ding,L.-Q. Huang,J.-G. Sun,C.-Z. Wang
Parasitic wasps rely on olfaction to locate their hosts in complex chemical environments. Odorant receptors (ORs) function together with well-conserved odorant coreceptors (ORcos) to determine the sensitivity and specificity of olfactory reception. Campoletis chlorideae (Hymenoptera: Ichneunmonidae) is a solitary larval endoparasitoid of the cotton bollworm, Helicoverpa armigera , and some other noctuid species . To understand the molecular basis of C. chlorideae ’s olfactory reception, we sequenced the transcriptome of adult male and female heads (including antennae) and identified 211 OR transcripts, with 95 being putatively full length. The tissue expression profiles, as assessed by reverse-transcription PCR, showed that seven OR s were expressed only or more highly in female antennae. Their functions were analysed using the Xenopu slaevis oocyte expression system and two-electrode voltage-clamp recordings. CchlOR62 was tuned to cis -jasmone, which was attractive to female C. chlorideae adults and H. armigera larvae in the subsequent behavioural assays. Further bioassays using caged plants showed that the parasitism rate of H. armigera larvae by C. chlorideae on cis -jasmone-treated tobacco plants was higher than on the control plants. Thus, cis -jasmone appears to be an important infochemical involved in the interactions of plants, H. armigera and C. chlorideae , and CchlOR62 mediates the attractiveness of cis -jasmone to C. chlorideae .
研究领域:
昆虫学
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分子生物学
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生态学
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高影响因子
Arthropod-Plant Interactions
·
2026
·Vol. 20
·期 5
·71
·
IF 1.7
Mao Jie-Wen,Luo Qian-Wen,Duan Shao-Ting,Zhang Meng-Hao,Liu Xiao-Guang,Guo Xian-Ru,Liu Yan-Min,Li Wei-Zheng
The specialist Helicoverpa assulta and the generalist Helicoverpa armigera are closely related species in Noctuidae. To elucidate the chemical basis underlying their differential oviposition responses to tomato, we compared the oviposition and walking responses of adult females and larvae of both species to tomato volatiles as well as derived synthetic blends. Dichloromethane and hexane extracts of tomato leaves deterred oviposition by H. assulta females. In contrast, all three extracts significantly attracted oviposition by H. armigera females. The components of the dichloromethane extract of tomato leaves were classified according to biosynthetic pathways (acetylmalonate, acetyl‑mevalonate, and shikimate pathways), and four blends were prepared based on their relative percentages in the extract: Blend 1 (green leaf volatiles), Blend 2 (aromatic compounds), Blend 3 (terpenoids), and Blend 4 (the full blend, contained all components that contained in the Blends 1 ~ 3). All blends significantly deterred oviposition by H. assulta females, with Blend 4 being the most effective. Only Blends 2 and 3 significantly attracted oviposition by H. armigera females. Larval walking bioassays on a locomotion compensator indicat that the differential host use is attributable to adult oviposition preference, rather than to larval olfactory discrimination between host and non-host volatiles. In field trials, the full blend effectively reduced egg deposition by H. assulta rather than H. armigera on tobacco plants. All together, the oviposition deterrence of H. assulta by tomato appears to be regulated by a “partial blend” of compounds commonly found across the plant kingdom, not by tomato-specific unique components.
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高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2016
·Vol. 17
·期 4
·493
·
IF 3.257
Yongqiang Li,Jianwei Liu,Mei Lu,Zhiqing Ma,Chongling Cai,Yonghong Wang,Xing Zhang
Carboxylesterasesare an important class of detoxification enzymes involved in insecticide resistance in insects. A subgroup ofHelicoverpa armigeraesterases, known as Clade 001, was implicated in organophosphate and pyrethroid insecticide resistance due to their overabundance in resistant strains. In this work, a novel carboxylesterasegene001DofH. armigerafrom China was cloned, which has an open reading frame of 1665 nucleotides encoding 554 amino acid residues. We used a series of fusion proteins to successfully express carboxylesterase 001D inEscherichia coli. Three different fusion proteins were generated and tested. The enzyme kinetic assay towards 1-naphthyl acetate showed all three purified fusion proteins are active with aKcat between 0.35 and 2.29 s−1, and aKm between 7.61 and 19.72 μM. The HPLC assay showed all three purified fusion proteins had low but measurable hydrolase activity towardsβ-cypermethrin and fenvalerate insecticides (specific activities ranging from 0.13 to 0.67 μM·min−1·(μM−1·protein)). The enzyme was stable up to 40 °C and at pH 6.0–11.0. The results imply that carboxylesterase 001D is involved in detoxification, and this moderate insecticide hydrolysis may suggest that overexpression of the gene to enhance insecticide sequestration is necessary to allow carboxylesterases to confer resistance to these insecticides inH. armigera.Keywords:Helicoverpaarmigera;carboxylesterase;pyrethroid;heterologous expression
研究领域:
昆虫学
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分子生物学
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高影响因子
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
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2021
·
IF 3.963
Jing-jing Xu,Yong-mei Chang,Mei Lu,Yuan Tie,Yan-ling Dong,Guang-you Chen,Zhi-qing Ma,Xi-li Liu,Yong-qiang Li
Carboxylesterases (CarEs) usually play critical roles in the detoxification of toxic chemicals and therefore may be involved in insecticide resistance in agricultural pests. Previous work has shown that CarE 001C from Helicoverpa armigera was able to metabolize the isomers of cypermethrin and fenvalerate . In this study, seven mutants of CarE 001C with single amino acid substitution were produced and expressed in the Escherichia coli. Enzyme kinetic analysis indicated that all seven mutations dramatically reduced enzymatic activities toward the generic substrate α -naphthyl acetate, but in vitro metabolism assay showed that two of the mutations, H423I and R322L, significantly improved hydrolase activities toward fenvalerate, with their recorded specific activities being 3.5 and 5.1 nM·s −1 ·mg −1 proteins, respectively. Further, thermostability assay showed that the stability of one mutant enzyme was enhanced. This study will help us better understand the potential of CarEs in insecticide detoxification and resistance in H. armigera .
研究领域:
昆虫学
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生物化学
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分子生物学
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高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2020
·
IF 4.192
Yong-Qiang Li,Li-Sha Bai,Cai-Xia Zhao,Jing-Jing Xu,Zhong-Juan Sun,Yan-Ling Dong,De-Xian Li,Xi-Li Liu,Zhi-Qing Ma
Insect carboxylesterases are major enzymes involved in metabolism of xenobiotics including insecticides. Two carboxylesterase genes, CarE001A and CarE001H, were cloned from the destructive agricultural pest Helicoverpa armigera. Quantitative real-time polymerase chain reaction showed that CarE001A and CarE001H were predominantly expressed in fat body and midgut, respectively; developmental expression analyses found that the expression levels of both CarEs were significantly higher in fifth-instar larvae than in other life stages. Recombinant CarE001A and CarE001H expressed in the Escherichia coli exhibited high enzymatic activity toward α-naphthyl acetate. Inhibition assays showed that organophosphates had strong inhibition on CarEs activity compared to pyrethroids. Metabolism assays indicated that CarE001A and CarE001H were able to metabolize β-cypermethrin and λ-cyhalothrin. Homology modeling and molecular docking analyses demonstrated that β-cypermethrin could fit nicely into the active pocket of both carboxylesterases. These results suggested that CarE001A and CarE001H could play important roles in the detoxification of pyrehtroids in H. armigera.
研究领域:
昆虫学
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分子生物学
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农药毒理学
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高影响因子
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
·
2019
·
IF 2.87
Li-sha Bai,Cai-xia Zhao,Jing-jing Xu,Chuan Feng,Yong-qiang Li,Yan-ling Dong,Zhi-qing Ma
Carboxylesterases (CarEs) are a major class of detoxification enzymes involved in insecticide resistance in various insect species. In this study, a novel CarE 001G was isolated from the cotton bollworm Helicoverpa armigera , one of the most destructive agricultural insect pests . The open reading frame of 001G has 2244 nucleotides and putatively encodes 747 amino acid residues. The deduced CarE possessed the highly conserved catalytic triads(Ser-Glu-His) and pentapeptide motifs (Gly-X-Ser-X-Gly), suggesting 001G is biologically active. The truncated 001G was successfully expressed in Escherichia coli , and the recombinant proteins were purified and tested. The enzyme kinetic assay showed the purified proteins could catalyze two model substrates, α-naphthyl acetate and β-naphthyl acetate, with a kcat of 8.8 and 2.3 s −1 , a K m of 9.6 and 16.2 μM, respectively. The inhibition study with pyrethroid , organophosphate and neonicotinoid insecticides showed different inhibition profile against the purified CarE. The HPLC assay demonstrated that the purified proteins were able to metabolize β -cypermethrin, λ-cyhalothrin and fenvalerate insecticides, exhibiting respective specific activities of 1.7, 1.4 and 0.5 nM/min/mg protein. However, the purified proteins were not able to metabolize the chlorpyrifos , parathion-methyl, paraoxon-ethyl and imidacloprid . The modeling and docking analyses consistently demonstrated that the pyrethroid molecule fits snugly into the catalytic pocket of the CarE 001G. Collectively, our results suggest that 001G may play a role in pyrethroids detoxification in H. armigera .
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高影响因子
ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY
·
2024
·Vol. 117
·期 3
·e70004
·
IF 1.5
Kai Tian,Jiang Zhu,Xinghui Qiu
Furanocoumarins are a class of chemical compounds with phototoxic properties. For herbivores, efficient detoxification of such defense compounds is the prerequisite to feed successfully on furanocoumarin-containing plants. The cotton bollworm Helicoverpa armigera is a very important polyphagous pest in agriculture, but how it copes with toxic furanocoumarins in some of its host plants is not well understood. Given that cytochrome P450s are well known for their capacity in xenobiotic metabolism, this study attempted to explore the potential roles of cytochrome P450s in furanocoumarin transformation in this pest. Our data showed that two linear structures (psoralen and xanthotoxin) could be metabolized by three recombinant CYP9A enzymes, but no detectable depletion was observed for the linear one with the 8-dimethylallyloxy substituent on the coumarin moiety (imperatorin) and the angular furanocoumarin (angelicin). Initial epoxidation of the double bond connecting C2' and C3' of the furano ring following by cleavage of the epoxidated furan ring, leading to the formation of more soluble, less reactive and nonphotosensitizing metabolites, was identified as a common mechanism of linear furanocoumarin metabolism using a quadrupole/time-of-flight (Q-TOF) mass spectrometry interfaced with a high performance liquid chromatography (HPLC) system. Our data demonstrated that multiple P450s were involved in the detoxification of linear furanocoumarins in the cotton bollworm. These findings contribute to a better understanding of the biochemical basis of adaptation to plant defense chemicals in this economically important pest. Summary CYP9A12, CYP9A14, and CYP9A17 are capable of metabolizing psoralen and xanthotoxin. Epoxidation of the C2'−C3' double bond of the furano ring is the common pathway. The three CYP9A enzymes exhibit no detectable activity against angelicin and imperatorin.
研究领域:
昆虫学
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生化与分子生物学
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高影响因子
JOURNAL OF ECONOMIC ENTOMOLOGY
·
2009
·Vol. 102
·期 2
·708-716
·
IF 1.346
Mahon R. J.,Olsen K. M.
Bollgard II cotton (which expresses two Bt insecticidal genes cry1Ac/cry2Ab) and conventional cotton, grown in the laboratory or field and sampled at different stages, was exposed to Helicoverpa armigera (Hübner) larvae of three genotypes: homozygous for resistance to Cry2Ab; homozygous for susceptibility to Cry2Ab, and heterozygous for resistance. Survival of all genotypes was limited on Bollgard II but increased as plants aged. This was particularly the case for homozygous resistant individuals, with 8.5% of this genotype surviving to pupation on mature cotton. The increasing survival is assumed to be caused by the decline in the titer of Cry1Ac toxin after flowering in Bollgard II because Cry2Ab homozygous resistant larvae can tolerate high levels of Cry2Ab toxin. Larvae heterozygous for resistance performed no better on Bollgard II than homozygous susceptible larvae. Survivors on Bollgard II grew more slowly and produced smaller pupae that yielded adults with reduced longevity and fecundity. When reared on conventional cotton, all genotypes generally performed equally, indicating an absence of fitness costs associated with Cry2Ab resistance under the conditions examined.
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高影响因子
Insect Science
·
2020
·Vol. 28
·期 6
·1756-1765
·
IF 2.791
Shan Wang,Min Zhang,Jinyong Huang,Leyao Li,Kaiyuan Huang,Yuting Zhang,Yalu Li,Zhongyuan Deng,Xinzhi Ni,Xianchun Li
Genetically engineered crops simultaneously produce defensive allelochemicals and Bacillus thuringiensis (Bt) toxin proteins to kill some of the world's most devastating insect pests. How the two types of toxins, when ingested sequentially or simultaneously, interact at both lethal and sublethal doses in these pests remains underexplored. Here, we examined the toxicological interactions between the Bt toxin Cry1Ac and the flavonoid allelochemical flavone in Helicoverpa armigera . Simultaneous exposure of H. armigera neonates to lethal doses (LC 25 ) of Cry1Ac and flavone caused a mortality significantly higher than that of either toxin alone and their expected additive mortality. Preexposure for 24 h to a sublethal dose (LC 10 ) of Cry1Ac followed by 6-d simultaneous exposure to the same dose of Cry1Ac plus a lethal dose (1.6 mg/g diets, LC 50 ) of flavone resulted in a mortality significantly higher than that of the LC 50 dose of flavone alone and the expected additive mortality of the LC 50 dose of flavone plus the LC 10 dose of Cry1Ac. One-day preexposure to the sublethal dose (LC 10 ) of flavone followed by 6-d simultaneous exposure to the LC 50 dose (6 ng/cm 2 ) of Cry1Ac plus the LC 10 dose of flavone yielded a mortality significantly higher than that of the LC 50 dose of Cry1Ac but similar to the expected additive mortality of the LC 50 dose of Cry1Ac plus the LC 10 dose of flavone. The results suggest that Cry1Ac induces and synergizes the toxicity of flavone against H. armigera larvae.
研究领域:
植物学
·
昆虫学
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遗传工程
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PubMed
高影响因子
危险品化学品经营许可证（带存储）