Chemical insecticides targeting the digestive system of diamondback moth(DBM),Plutella xylostella,have not been developed.The discovery of an insecticide with novel mode of action is a challenge for the control of DBM...Chemical insecticides targeting the digestive system of diamondback moth(DBM),Plutella xylostella,have not been developed.The discovery of an insecticide with novel mode of action is a challenge for the control of DBM.In this study,a class of selenium-and difluoromethyl-modified azoles(fluoroazole selenoureas,FASU)were designed and synthesized for the control of DBM.Of these azoles,compound B4 showed the highest insecticidal activity against DBM.The LC50of third-and second-instar larvae reached 32.3 and 4.6μg mL^(–1),respectively.The midgut tissue of larvae was severely disrupted,and the larval intestinal tissue was dotted with unique red spots after treatment with compound B4.Compound B4 led to disintegration of the peritrophic matrix,swelling of the midgut epithelium,fracture of the microvilli,and extensive leakage of cellular debris in the midgut lumen.Surviving larvae grew very slowly,and the larval duration was significantly prolonged after exposure to compound B4 at sublethal doses(LC10,LC25and LC50).Furthermore,the pupation rate,emergence rate and pupae weight were significantly decreased.Compound B4 also induced abnormal pupae,causing adults to be trapped in the cocoon or failure to fly due to twisted wings.These results demonstrated that FASU could reduce the population of DBM in sublethal doses.FASU is the first synthetic insecticidal lead compound that has been shown to disrupt the midgut tissue of the larvae of DBM,and its mode of action totally differs from that of commercial chemical insecticides.展开更多
The identification of functional midgut receptors for pesticidal proteins produced by Bacillus thuringiensis(Bt)is critical for deciphering the molecular mechanism of Bt resistance in insects.Reduced expression of the...The identification of functional midgut receptors for pesticidal proteins produced by Bacillus thuringiensis(Bt)is critical for deciphering the molecular mechanism of Bt resistance in insects.Reduced expression of the PxABCB1 gene was previously found to be associated with Cry1Ac resistance in the diamondback moth,Plutella xylostella(L.).To directly validate the potential receptor role of PxABCB1 and its contribution to Bt Cry1Ac toxicity in P.xylostella,we used CRISPR/Cas9 to generate a homozygous knockout ABCB1KO strain with a 5-bp deletion in exon 3 of its gene.The ABCB1KO strain exhibited a 63-fold resistance to Cry1Ac toxin compared to the parental DBM1Ac-S strain.Intriguingly,the ABCB1KO strain also exhibited significant increases in susceptibility to abamectin and emamectin benzoate.No changes in susceptibility to various other Bt Cry proteins or synthetic insecticides were observed.The knockout strain exhibited no significant fitness costs.Overall,our study indicates that PxABCB1 can protect the insect against avermectin insecticides on one hand,while on the other hand it facilitates the toxic effect of the Bt Cry1Ac toxin.The results of this study will help to inform integrated pest management approaches against this destructive pest.展开更多
The acetylcholinesterase 2(AChE2)cloned from Plutella xylostella was first successfully expressed in methylotrophic yeast Pichia pastoris GS115.One transformant with high-level expression of the recombinant AChE(rAChE...The acetylcholinesterase 2(AChE2)cloned from Plutella xylostella was first successfully expressed in methylotrophic yeast Pichia pastoris GS115.One transformant with high-level expression of the recombinant AChE(rAChE,23.2 U mL^(-1)in supernatant)was selected by plating on increasing concentrations of antibiotic G418 and by using a simple and specific chromogenic reaction with indoxyl acetate as a substrate.The maximum production of r ACh E reached about 11.8 mg of the enzyme protein per liter of culture.The r ACh E was first precipitated with ammonium sulfate(50%saturation)and then purified with procainamide affinity column chromatography.The enzyme was purified 12.1-fold with a yield of 22.8%and a high specific activity of 448.3 U mg^(-1).It was sensitive to inhibition by methamidophos and pirimicarb,the calculated 50% inhibitory concentration(IC_(50))values of the two pesticides were 0.357 and 0.888 mg L^(-1),respectively,and the calculated 70% inhibitory concentration(IC_(70))values were 0.521 and 0.839 mg L^(-1),respectively.The results suggested that it has a potential application in the detection of pesticide residues.展开更多
Plutella xylostella is the main pest of cruciferae plants in the worldwide fields.The volatiles released from host plants serve vital roles in host-finding and oviposition behavior.Electroantennograms were recorded fr...Plutella xylostella is the main pest of cruciferae plants in the worldwide fields.The volatiles released from host plants serve vital roles in host-finding and oviposition behavior.Electroantennograms were recorded from male and female Plutella xylostella to 9 different plant volatiles(cabbage Brassica oleracea L.var.capitata,baby bokchoi Brassica chinensis L.,broccoli Brassica oleracea L.var.botrytis L.,Chinese cabbage Brassica pekinensis Rupr.,Radish Raphanus sativus L.,towel gourd Luffa Cylindrica Roem.,eggplant Solanum melongena L.,tomato Solanum lycopersicum,pepper Capsicum annuum L.) in healthy/injured status.The statistic analysis show there is a significant difference of EAG relative values between cruciferae and non-cruciferae volatiles.The EAG relative values of injured plant volatiles to both male and female changed a lot during the tests.Multiple-ANOVA analysis represents cross factors(sex,host-plant,plant status) showed a great interactive impacts to the EAG-RV.展开更多
Carboxylesterase(CarE)was considered as important phase-I detoxifying enzymes which participated in detoxification of different types of insecticides.Up-regulation of CarE genes has been proved playing a major role in...Carboxylesterase(CarE)was considered as important phase-I detoxifying enzymes which participated in detoxification of different types of insecticides.Up-regulation of CarE genes has been proved playing a major role in insecticide resistance in many pest insects,but its involvement in resistance to insecticides in Plutella xylostella has been rarely reported.In this study,a CarE cDNA named PxαE8 was identified in P.xylostella,which has an open reading frame of 1599 nucleotides and putatively encodes 532 amino acids.The investigation of spatial expression profiles of PxαE8 revealed that it was expressed in all developmental stages,especially in larvae and adults.The body part/tissue-specific expression profiles showed that the PxαE8 mainly expressed in fat body,malpighian tubule and hemolymph of larvae.Further,the relative expression of PxαE8 in two multi-resistant field populations,Hainan(HN)and Guangdong(GD)populations,was found 24.4-and 15.5-fold higher than that in susceptible population,respectively.Knockdown of PxαE8 by RNA interference dramatically increased the mortalities of larvae of HN population treated with LC_(50) of beta-cypermethrin and phoxim by 25.3 and 18.3%,respectively.These results suggested that up-regulation of PxαE8 was involved in resistance to both beta-cypermethrin and phoxim in P.xylostella,which shed light on further understanding of molecular mechanisms of multi-insecticide-resistance in P.xylostella and other pest insects.展开更多
Choriogenesis is the last step of insect oogenesis,a process by which the chorion polypeptides are produced by the follicular cells and deposited on the surface of oocytes in order to provide a highly specialized prot...Choriogenesis is the last step of insect oogenesis,a process by which the chorion polypeptides are produced by the follicular cells and deposited on the surface of oocytes in order to provide a highly specialized protective barrier to the embryo.The essential features of chorion genes have yet to be clearly understood in the diamondback moth,Plutella xylostella,a worldwide Lepidoptera pest attacking cruciferous crops and wild plants.In this study,complete sequences for 15 putative chorion genes were identified,and grouped into A and B classes.Phylogenetic analysis revealed that both classes were highly conserved and within each,branches are also species-specific.Chorion genes from each class were located in pairs on scaffolds of the P.xylostella genome,some of which shared the common promoter regulatory region.All chorion genes were highly specifically expressed in the P.xylostella adult females,mostly in the ovary with full yolk,which is a crucial period to build the shells of the eggs.RNAi-based knockdown of chorion-1,which is located on the Px_scaffold 6 alone,although had no effect on yolk deposition,resulted in smaller eggs and sharply reduced hatchability.Additionally,inhibition of PxCho-1 expression caused a less dense arrangement of the columnar layers,reduced exochorion roughness and shorter microvilli.Our study provides the foundation for exploring molecular mechanisms of female reproduction in P.xylostella,and for making use of chorion genes as the potential genetic-based molecular target to better control this economically important pest.展开更多
Orphan genes are genes with no sequence homologues in other species. Here, we identified two orphan genes, namely, Tssor-3 and Tssor-4, in Plutella xylostella. Both genes contained a signal peptide sequence, suggestin...Orphan genes are genes with no sequence homologues in other species. Here, we identified two orphan genes, namely, Tssor-3 and Tssor-4, in Plutella xylostella. Both genes contained a signal peptide sequence, suggesting their functions as secreted proteins. Expression pattern analysis based on real-time quantitative PCR(qPCR) showed that both orphan genes were specifically expressed in all male gonads except the testes. The expression of both the orphan genes peaked at the male adult stage. Immunofluorescence assays suggested that the two proteins were seminal proteins, indicating their potential roles in male reproductive regulation. To further explain their functions, we knocked down the expression of these two genes by RNA interference(RNAi). The results showed that the expression of Tssor-3 and Tssor-4 was significantly downregulated at 24 h after injection compared to that of the controls. Biological assays showed that the number of laid eggs and the hatching rate of offspring eggs were significantly reduced when the expression of Tssor-3 and Tssor-4 was reduced, suggesting that the two orphan genes played a role in male fertility in P. xylostella. Our results provide evidence that orphan genes are involved in male reproductive regulation, which is important for male fitness during evolution.展开更多
The insecticide chlorantraniliprole exhibits good efficacy and plays an important role in controlling the diamondback moth, Plutella xylostella Linnaeus. However, resistance to chlorantraniliprole has been observed re...The insecticide chlorantraniliprole exhibits good efficacy and plays an important role in controlling the diamondback moth, Plutella xylostella Linnaeus. However, resistance to chlorantraniliprole has been observed recently in some field populations. At present study, diamondback moths with resistance to chlorantraniliprole(resistant ratio(RR) was 82.18) for biochemical assays were selected. The assays were performed to determine potential resistance mechanisms. The results showed that the selected resistant moths(GDLZ-R) and susceptible moth could be synergized by known metabolic inhibitors such as piperonyl butoxide(PBO), triphenyl phosphate(TPP) and diethyl-maleate(DEM) at different levels(1.68-5.50-fold and 2.20-2.89-fold, respectively), and DEM showed the maximum synergism in both strains. In enzymes assays, a high level of glutathione-S-transferase(GST) was observed in the resistant moth, in contrast, moths that are susceptible to the insecticide had only 1/3 the GST activity of the resistant moths. The analysis of short-term exposure of chlorantraniliprole on biochemical response in the resistant strain also showed that GST activity was significantly elevated after exposure to a sub-lethal concentration of chlorantraniliprole(about 1/3 LC50, 12 mg L-1) 12 and 24 h, respectively. The results show that there is a strong correlation between the enzyme activity and resistance, and GST i s likely the main detoxification mechanism responsible for resistance to chlorantraniliprole in P. xylostella L., cytochrome P450 monooxygenase(P450) and carboxy-lesterase(Car E) are involved in to some extent.展开更多
The toxicities of fenvalerate (20% EC) to the 3rd instar larvae of diamondback moth (DBM), Plutella xylostella (L.), reared on three host plants viz., radish, oilseed rape, and cabbage were tested. The LC50 values of ...The toxicities of fenvalerate (20% EC) to the 3rd instar larvae of diamondback moth (DBM), Plutella xylostella (L.), reared on three host plants viz., radish, oilseed rape, and cabbage were tested. The LC50 values of fenvalerate to the 3rd instar larvae of DBM varied with host plants, however, there wasn’t any significant difference among them (P > 0.05). Similarly, DBM fed on three host plants had same pupal weight, pupal period, pupation rate, adult emergence rate, female ratio, and fecundity. The activity of juvenile hormone esterase (JHE, EC 3.1.1.1) in the 3rd instar larvae of DMB did not significantly vary with host plants, either. These suggested that DBM had similar fitness on the three host plant species. When fed on the host plants pretreated with fenvalerate at the concentrations equivalent to LC20, LC50 and LC80, the pupation rate, pupal weight, adult emergence rate, female ratio, fecundity, and JHE activity of the tested insects were declined as compared with insects in control treatments fed on the same host plant species. Furthermore, the pupal period of the tested insects was extended after fenvalerate treatment. The decrease in JHE activity after fenvalerate treatment in the tested insects could partly explain the changes in the mentioned growth parameters. Whether the role of fenvalerate in the inhibition of JHE activity could serve as a new way to control DBM needs further investigation.展开更多
Plutella xylostella(L.)(Plutellidae) is an important agricultural pest throughout the world. In this study, the morphology of antennal and mouthpart sensilla in the larvae and adults of P. xylostella(L.) was observed ...Plutella xylostella(L.)(Plutellidae) is an important agricultural pest throughout the world. In this study, the morphology of antennal and mouthpart sensilla in the larvae and adults of P. xylostella(L.) was observed by using a scanning electron microscope. The larval antennae possess six sensilla basiconica, two sensilla chaetica and one sensillum styloconicum. Larval mouthparts possess six types of sensilla: sensilla chaetica, sensilla digitiformia, sensilla epipharyngeal, sensilla basiconica, sensilla styloconica and sensilla placodea. In the adult, seven types of sensilla are found on the antennae in males and six types of sensilla(sensilla basiconica absent) occur in females. Sexual dimorphism is also found in the number and size of these sensilla on the antennae of adults. We describe for the first time the five types of sensilla on the mouthparts of the adult of P. xylostella. This study provides useful information for further research into the function of these sensilla, and better understanding the behavioral mechanisms involved in pest control.展开更多
The effects of kojic acid on phenoloxidase (PO) of Plutella xylostella were investigated, when it had been partially purified by 40% saturated [(NH4)2SO4] and Sephadex G-100 gel filtration. Kojic acid showed inhibitor...The effects of kojic acid on phenoloxidase (PO) of Plutella xylostella were investigated, when it had been partially purified by 40% saturated [(NH4)2SO4] and Sephadex G-100 gel filtration. Kojic acid showed inhibitory effects on both monophenolase and o-diphenolase activity of the PO. The inhibitor concentrations leading to 50% (IC50) activity lost were estimated to be 0.07 mmol L-1 for monophenolase and 1 mmol L-1 for diphenolase, respectively. Kojic acid can also prolong the lag time of PO for oxidation of L-tyrosine. The inhibition kinetics were analyzed by Lineweaver-Burk plots and kojic acid was found to be a reversible competitive inhibitor with the Ki of 0.47 mmol L-1. The ability of kojic acid to inhibit the enzyme activity may be associated with its ability to chelate copper at the active site. In addition, the iron ion was found to shorten the lag time obviously, but have no important effect on the monophenolase activity.展开更多
Metaflumizone is a novel sodium channel blocker insecticide, which has been registered for controling the diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae) in China. It is unavoidable for DBMs to ...Metaflumizone is a novel sodium channel blocker insecticide, which has been registered for controling the diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae) in China. It is unavoidable for DBMs to be exposed to sublethal dose of metaflumizone in brassicaceous vegetable field. Sublethal effects of metaflumizone at LC 15 (1.06 mg L-1) and LC 25 (2.03 mg L-1) on the biological characteristics were investigated. Pupation rate, pupal period and pupal weight were significantly declined comparing with the control (P=0.05) when third instar larvae were exposed to LC 15 and LC 25 of metaflumizone. Comparing the control group to LC 15 and LC 25 treatment groups, there were significant differences in the development periods of eggs, first instar larvae, pupae and total preoviposition period. The peak of age-specific fecundity in LC 15 and LC 25 treatment groups was lagged behind control group. Mean values of intrinsic rate of increase (r m ), net reproductive rate (R 0 ) and finite rate of increase (λ) observed from the LC 15 and LC 25 treatment groups were lower than those from the control group. But mean values of gross reproduction rate (GRR) was not different. The mean generation time (T) of the treatment groups was prolonged. Whether sublethal doses of metaflumizone could stimulate reproduction in the long term needs further investigation on continuous generations.展开更多
Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth(DBM; Plutella xylostella). The trichoid sensilla were th...Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth(DBM; Plutella xylostella). The trichoid sensilla were the most abundant sensory organ, and the male moth antennae host significantly more trichoid sensilla than female moth antennae. Conversely, basiconic and coeloconic sensilla were found more frequently on female than on male antennae. We performed experiments with various degrees of antennal ablation and demonstrated that DBM antennae played a key role in the control of mating and oviposition. We found that neither oviposition preference nor mating behaviors changed significantly when less than 1/4 of both antennae were removed. However, there was a significant behavioral change when the antennae were ablated by more than half. As the length of the antenna was shortened, the successful mating rate decreased and mating peak was delayed. An otherwise consistent host preference for oviposition was eliminated when both antennae were completely removed. Furthermore, we found that the number of trichoid sensilla was positively correlated with mating rate and oviposition preference. However, the numbers of basiconic and coeloconic sensilla were not correlated with mating rate and mating peak, but highly correlated with oviposition preference. Taken together, our results indicate that antennal sensory information plays a critical role in the mating and oviposition behaviors of this economically important pest.展开更多
Strategies for insect population control are currently targeting chemical communication at the molecular level. The diamondback moth Plutella xylostella represents one of the most serious pests in agriculture, however...Strategies for insect population control are currently targeting chemical communication at the molecular level. The diamondback moth Plutella xylostella represents one of the most serious pests in agriculture, however detailed information on the proteins mediating olfaction in this species is still poor. This species is endowed with a repertoire of a large number of olfactory receptors and odorant binding proteins(OBPs). As a contribution to map the specificities of these chemical sensors in the moth and eventually unrave l the complexity of chemodetection, we have measured the affinities of three selected OBPs to a series of potential odorants. Three proteins are highly divergent in their amino acid sequences and show markedly different expression profiles. In fact, PxylOBP3 is exclusively expressed in the antennae of both sexes, PxylOBP9 is male specific and present only in antennae and reproductive organs, while PxylOBP19, an unusual OBP with nine cysteines, is ubiquitously present in all the organs examined. Such expression pattern suggests that the last two proteins may be involved in non-chemosensory functions. Despite such differences, the three OBPs exhibit similar binding spectra, together with high selectivity. Among the 26 natural compounds tested, only two proved to be good ligands, retinol and coniferyl aldehyde. This second compound is particularly interesting being part of the chemical pathway leading to regeneration of lignin, one of the defense strategies of the plant against insect attack, and might find applications as a repellent for P. xylostella and other pests.展开更多
With the bioguided fractionation of the ethanol extracts from the leaves of Momordica charantia, we obtained two most active compounds against the feeding of the diamondback moth, Plutella xylostella larvae. The antif...With the bioguided fractionation of the ethanol extracts from the leaves of Momordica charantia, we obtained two most active compounds against the feeding of the diamondback moth, Plutella xylostella larvae. The antifeedant activity of momordicine I and momordicine II against the second and the third instar larvae of Plutella xylostella were tested using leaf discs of cabbage in the laboratory. The results showed that momordicin I and momordicin II had significant antifeedant activity on the larvae of P. xylostella, and momordicin II was more active than momordicin I. The concentrations for 50% antifeedant effects (AFC50) of momordicin II against the second and the third instar larvae of P. xylostella were 76.69 and 116.24 μg mL-1, whereas that of momordicin I was 144.08 and 168.42 μg mL-1, respectively. In addition, momordicin I and momordicin II had significant inhibitive effect on the rate of weight gain and survival of P. xylostella larvae.展开更多
Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to lar...Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.展开更多
The changes of the proteome in Arabidopsis thaliana leaves were examined by specialist Plutella xylostella.Analysis of about 1100 protein spots on each 2DE gel revealed 38 differentially expressed protein spots in abu...The changes of the proteome in Arabidopsis thaliana leaves were examined by specialist Plutella xylostella.Analysis of about 1100 protein spots on each 2DE gel revealed 38 differentially expressed protein spots in abun-dance of which 34 proteins were identified by MALDI-TOF/TOF MS.Among the insect feeding responsive proteins,a few proteins involved in carbon metabolism were identified including proteins associated with the Calvin cycle in the chloroplast and TCA cycle in the mitochondria,indicating carbon metabolism related proteins may play crucial roles in induced defense response in plants under insect infestation.The analysis elucidates the subcellular location of proteins demonstrates that about 50% of proteins are in the chloroplast,which shows the chloroplast has a key role in the insect feeding response for plant.Gene expression analysis of 10 different proteins by quantitative real-time PCR shows that four proteins of the mRNA level were correlated well with the protein level.This study further dissected the nature of insect infestation as a stress signal and some novel insect feeding responsive proteins identified may play an important role in induced defence machanism for plant.展开更多
基金financially supported by funding from the Guangdong Basic and Applied Basic Research Foundation,China(2019B151502052)the Program of Science and Technology of Guangzhou,China(202002030295)。
文摘Chemical insecticides targeting the digestive system of diamondback moth(DBM),Plutella xylostella,have not been developed.The discovery of an insecticide with novel mode of action is a challenge for the control of DBM.In this study,a class of selenium-and difluoromethyl-modified azoles(fluoroazole selenoureas,FASU)were designed and synthesized for the control of DBM.Of these azoles,compound B4 showed the highest insecticidal activity against DBM.The LC50of third-and second-instar larvae reached 32.3 and 4.6μg mL^(–1),respectively.The midgut tissue of larvae was severely disrupted,and the larval intestinal tissue was dotted with unique red spots after treatment with compound B4.Compound B4 led to disintegration of the peritrophic matrix,swelling of the midgut epithelium,fracture of the microvilli,and extensive leakage of cellular debris in the midgut lumen.Surviving larvae grew very slowly,and the larval duration was significantly prolonged after exposure to compound B4 at sublethal doses(LC10,LC25and LC50).Furthermore,the pupation rate,emergence rate and pupae weight were significantly decreased.Compound B4 also induced abnormal pupae,causing adults to be trapped in the cocoon or failure to fly due to twisted wings.These results demonstrated that FASU could reduce the population of DBM in sublethal doses.FASU is the first synthetic insecticidal lead compound that has been shown to disrupt the midgut tissue of the larvae of DBM,and its mode of action totally differs from that of commercial chemical insecticides.
基金the Laboratory of Lingnan Modern Agriculture Project,China(NT2021003)National Natural Science Foundation of China(32022074,32221004 and 32172458)Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables,Chinese Academy of Agricultural Sciences,and the Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS-CSCB-202303)。
文摘The identification of functional midgut receptors for pesticidal proteins produced by Bacillus thuringiensis(Bt)is critical for deciphering the molecular mechanism of Bt resistance in insects.Reduced expression of the PxABCB1 gene was previously found to be associated with Cry1Ac resistance in the diamondback moth,Plutella xylostella(L.).To directly validate the potential receptor role of PxABCB1 and its contribution to Bt Cry1Ac toxicity in P.xylostella,we used CRISPR/Cas9 to generate a homozygous knockout ABCB1KO strain with a 5-bp deletion in exon 3 of its gene.The ABCB1KO strain exhibited a 63-fold resistance to Cry1Ac toxin compared to the parental DBM1Ac-S strain.Intriguingly,the ABCB1KO strain also exhibited significant increases in susceptibility to abamectin and emamectin benzoate.No changes in susceptibility to various other Bt Cry proteins or synthetic insecticides were observed.The knockout strain exhibited no significant fitness costs.Overall,our study indicates that PxABCB1 can protect the insect against avermectin insecticides on one hand,while on the other hand it facilitates the toxic effect of the Bt Cry1Ac toxin.The results of this study will help to inform integrated pest management approaches against this destructive pest.
基金supported by a grant from the Public Benefit Research Foundation of China (200903052)the Science and Technology Department of Guangdong Province, China (2009A020101003)
文摘The acetylcholinesterase 2(AChE2)cloned from Plutella xylostella was first successfully expressed in methylotrophic yeast Pichia pastoris GS115.One transformant with high-level expression of the recombinant AChE(rAChE,23.2 U mL^(-1)in supernatant)was selected by plating on increasing concentrations of antibiotic G418 and by using a simple and specific chromogenic reaction with indoxyl acetate as a substrate.The maximum production of r ACh E reached about 11.8 mg of the enzyme protein per liter of culture.The r ACh E was first precipitated with ammonium sulfate(50%saturation)and then purified with procainamide affinity column chromatography.The enzyme was purified 12.1-fold with a yield of 22.8%and a high specific activity of 448.3 U mg^(-1).It was sensitive to inhibition by methamidophos and pirimicarb,the calculated 50% inhibitory concentration(IC_(50))values of the two pesticides were 0.357 and 0.888 mg L^(-1),respectively,and the calculated 70% inhibitory concentration(IC_(70))values were 0.521 and 0.839 mg L^(-1),respectively.The results suggested that it has a potential application in the detection of pesticide residues.
基金The Knowledge Innovation Project of Chinese Academy of Sciences-Important Direction Projects (KSCX2-YW-N-42-04)
文摘Plutella xylostella is the main pest of cruciferae plants in the worldwide fields.The volatiles released from host plants serve vital roles in host-finding and oviposition behavior.Electroantennograms were recorded from male and female Plutella xylostella to 9 different plant volatiles(cabbage Brassica oleracea L.var.capitata,baby bokchoi Brassica chinensis L.,broccoli Brassica oleracea L.var.botrytis L.,Chinese cabbage Brassica pekinensis Rupr.,Radish Raphanus sativus L.,towel gourd Luffa Cylindrica Roem.,eggplant Solanum melongena L.,tomato Solanum lycopersicum,pepper Capsicum annuum L.) in healthy/injured status.The statistic analysis show there is a significant difference of EAG relative values between cruciferae and non-cruciferae volatiles.The EAG relative values of injured plant volatiles to both male and female changed a lot during the tests.Multiple-ANOVA analysis represents cross factors(sex,host-plant,plant status) showed a great interactive impacts to the EAG-RV.
基金supported by the National Natural Science Foundation of China (31371956, 31572023 and 31772186)
文摘Carboxylesterase(CarE)was considered as important phase-I detoxifying enzymes which participated in detoxification of different types of insecticides.Up-regulation of CarE genes has been proved playing a major role in insecticide resistance in many pest insects,but its involvement in resistance to insecticides in Plutella xylostella has been rarely reported.In this study,a CarE cDNA named PxαE8 was identified in P.xylostella,which has an open reading frame of 1599 nucleotides and putatively encodes 532 amino acids.The investigation of spatial expression profiles of PxαE8 revealed that it was expressed in all developmental stages,especially in larvae and adults.The body part/tissue-specific expression profiles showed that the PxαE8 mainly expressed in fat body,malpighian tubule and hemolymph of larvae.Further,the relative expression of PxαE8 in two multi-resistant field populations,Hainan(HN)and Guangdong(GD)populations,was found 24.4-and 15.5-fold higher than that in susceptible population,respectively.Knockdown of PxαE8 by RNA interference dramatically increased the mortalities of larvae of HN population treated with LC_(50) of beta-cypermethrin and phoxim by 25.3 and 18.3%,respectively.These results suggested that up-regulation of PxαE8 was involved in resistance to both beta-cypermethrin and phoxim in P.xylostella,which shed light on further understanding of molecular mechanisms of multi-insecticide-resistance in P.xylostella and other pest insects.
基金funded by the National Natural Science Foundation of China(32172404)the Natural Science Foundation of Fujian Province,China(2019J01666)+1 种基金the Fujian Agriculture and Forestry University Fund for Distinguished Young Scholars,China(xjq201903)the"111"Program-Innovation Center for Ecologically Based Pest Management of Subtropical Crops,Fujian Agriculture and Fo restry University,China。
文摘Choriogenesis is the last step of insect oogenesis,a process by which the chorion polypeptides are produced by the follicular cells and deposited on the surface of oocytes in order to provide a highly specialized protective barrier to the embryo.The essential features of chorion genes have yet to be clearly understood in the diamondback moth,Plutella xylostella,a worldwide Lepidoptera pest attacking cruciferous crops and wild plants.In this study,complete sequences for 15 putative chorion genes were identified,and grouped into A and B classes.Phylogenetic analysis revealed that both classes were highly conserved and within each,branches are also species-specific.Chorion genes from each class were located in pairs on scaffolds of the P.xylostella genome,some of which shared the common promoter regulatory region.All chorion genes were highly specifically expressed in the P.xylostella adult females,mostly in the ovary with full yolk,which is a crucial period to build the shells of the eggs.RNAi-based knockdown of chorion-1,which is located on the Px_scaffold 6 alone,although had no effect on yolk deposition,resulted in smaller eggs and sharply reduced hatchability.Additionally,inhibition of PxCho-1 expression caused a less dense arrangement of the columnar layers,reduced exochorion roughness and shorter microvilli.Our study provides the foundation for exploring molecular mechanisms of female reproduction in P.xylostella,and for making use of chorion genes as the potential genetic-based molecular target to better control this economically important pest.
基金supported by the Natural Science Foundation of Fujian Province, China (2020J01525)the National Natural Science Foundation of China (31320103922 and 31230061)the Major Science and Technology Projects in Fujian Province, China (2018NZ010100130)。
文摘Orphan genes are genes with no sequence homologues in other species. Here, we identified two orphan genes, namely, Tssor-3 and Tssor-4, in Plutella xylostella. Both genes contained a signal peptide sequence, suggesting their functions as secreted proteins. Expression pattern analysis based on real-time quantitative PCR(qPCR) showed that both orphan genes were specifically expressed in all male gonads except the testes. The expression of both the orphan genes peaked at the male adult stage. Immunofluorescence assays suggested that the two proteins were seminal proteins, indicating their potential roles in male reproductive regulation. To further explain their functions, we knocked down the expression of these two genes by RNA interference(RNAi). The results showed that the expression of Tssor-3 and Tssor-4 was significantly downregulated at 24 h after injection compared to that of the controls. Biological assays showed that the number of laid eggs and the hatching rate of offspring eggs were significantly reduced when the expression of Tssor-3 and Tssor-4 was reduced, suggesting that the two orphan genes played a role in male fertility in P. xylostella. Our results provide evidence that orphan genes are involved in male reproductive regulation, which is important for male fitness during evolution.
基金sponsored by the Special Fund for AgroScientific Research in the Public Interest of China (201103021)the President Foundation of Guangdong Academy of Agricultural Sciences, China (201206)the Guangdong Natural Science Foundation, China (S2013010012529)
文摘The insecticide chlorantraniliprole exhibits good efficacy and plays an important role in controlling the diamondback moth, Plutella xylostella Linnaeus. However, resistance to chlorantraniliprole has been observed recently in some field populations. At present study, diamondback moths with resistance to chlorantraniliprole(resistant ratio(RR) was 82.18) for biochemical assays were selected. The assays were performed to determine potential resistance mechanisms. The results showed that the selected resistant moths(GDLZ-R) and susceptible moth could be synergized by known metabolic inhibitors such as piperonyl butoxide(PBO), triphenyl phosphate(TPP) and diethyl-maleate(DEM) at different levels(1.68-5.50-fold and 2.20-2.89-fold, respectively), and DEM showed the maximum synergism in both strains. In enzymes assays, a high level of glutathione-S-transferase(GST) was observed in the resistant moth, in contrast, moths that are susceptible to the insecticide had only 1/3 the GST activity of the resistant moths. The analysis of short-term exposure of chlorantraniliprole on biochemical response in the resistant strain also showed that GST activity was significantly elevated after exposure to a sub-lethal concentration of chlorantraniliprole(about 1/3 LC50, 12 mg L-1) 12 and 24 h, respectively. The results show that there is a strong correlation between the enzyme activity and resistance, and GST i s likely the main detoxification mechanism responsible for resistance to chlorantraniliprole in P. xylostella L., cytochrome P450 monooxygenase(P450) and carboxy-lesterase(Car E) are involved in to some extent.
基金support for this work was provided by the National Natural Science Foundation of China(30971922)the Natural Science Foundation of Fujian Province, China (B0320003, B0410015, 2004J010, and2007F5021)+1 种基金the Science and Technology Innovation Foundation of Fujian Academy of Agricultural Science,China (STIF-Y07)the Program for New Century Excellent Talents in University of Fujian Province, China,to Associate Professor Gu Xiaojun
文摘The toxicities of fenvalerate (20% EC) to the 3rd instar larvae of diamondback moth (DBM), Plutella xylostella (L.), reared on three host plants viz., radish, oilseed rape, and cabbage were tested. The LC50 values of fenvalerate to the 3rd instar larvae of DBM varied with host plants, however, there wasn’t any significant difference among them (P > 0.05). Similarly, DBM fed on three host plants had same pupal weight, pupal period, pupation rate, adult emergence rate, female ratio, and fecundity. The activity of juvenile hormone esterase (JHE, EC 3.1.1.1) in the 3rd instar larvae of DMB did not significantly vary with host plants, either. These suggested that DBM had similar fitness on the three host plant species. When fed on the host plants pretreated with fenvalerate at the concentrations equivalent to LC20, LC50 and LC80, the pupation rate, pupal weight, adult emergence rate, female ratio, fecundity, and JHE activity of the tested insects were declined as compared with insects in control treatments fed on the same host plant species. Furthermore, the pupal period of the tested insects was extended after fenvalerate treatment. The decrease in JHE activity after fenvalerate treatment in the tested insects could partly explain the changes in the mentioned growth parameters. Whether the role of fenvalerate in the inhibition of JHE activity could serve as a new way to control DBM needs further investigation.
基金supported by the China Postdoctoral Science Foundation (2013M542388)the Postdoctoral Scientific Research Project in Shaanxi Province,China+1 种基金the Fundamental Research Funds for the Central Universities of China (2014YB087)the Agricultural Science and Technology Innovation in Shaanxi Province,China (2016NY-058)
文摘Plutella xylostella(L.)(Plutellidae) is an important agricultural pest throughout the world. In this study, the morphology of antennal and mouthpart sensilla in the larvae and adults of P. xylostella(L.) was observed by using a scanning electron microscope. The larval antennae possess six sensilla basiconica, two sensilla chaetica and one sensillum styloconicum. Larval mouthparts possess six types of sensilla: sensilla chaetica, sensilla digitiformia, sensilla epipharyngeal, sensilla basiconica, sensilla styloconica and sensilla placodea. In the adult, seven types of sensilla are found on the antennae in males and six types of sensilla(sensilla basiconica absent) occur in females. Sexual dimorphism is also found in the number and size of these sensilla on the antennae of adults. We describe for the first time the five types of sensilla on the mouthparts of the adult of P. xylostella. This study provides useful information for further research into the function of these sensilla, and better understanding the behavioral mechanisms involved in pest control.
基金The study was supperted by the State Science and Technology Commission of China(30270887).
文摘The effects of kojic acid on phenoloxidase (PO) of Plutella xylostella were investigated, when it had been partially purified by 40% saturated [(NH4)2SO4] and Sephadex G-100 gel filtration. Kojic acid showed inhibitory effects on both monophenolase and o-diphenolase activity of the PO. The inhibitor concentrations leading to 50% (IC50) activity lost were estimated to be 0.07 mmol L-1 for monophenolase and 1 mmol L-1 for diphenolase, respectively. Kojic acid can also prolong the lag time of PO for oxidation of L-tyrosine. The inhibition kinetics were analyzed by Lineweaver-Burk plots and kojic acid was found to be a reversible competitive inhibitor with the Ki of 0.47 mmol L-1. The ability of kojic acid to inhibit the enzyme activity may be associated with its ability to chelate copper at the active site. In addition, the iron ion was found to shorten the lag time obviously, but have no important effect on the monophenolase activity.
基金the Huazhong Agricultural University Scientific & Technological Self-Innovation Foundation, China (2009SC001)
文摘Metaflumizone is a novel sodium channel blocker insecticide, which has been registered for controling the diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae) in China. It is unavoidable for DBMs to be exposed to sublethal dose of metaflumizone in brassicaceous vegetable field. Sublethal effects of metaflumizone at LC 15 (1.06 mg L-1) and LC 25 (2.03 mg L-1) on the biological characteristics were investigated. Pupation rate, pupal period and pupal weight were significantly declined comparing with the control (P=0.05) when third instar larvae were exposed to LC 15 and LC 25 of metaflumizone. Comparing the control group to LC 15 and LC 25 treatment groups, there were significant differences in the development periods of eggs, first instar larvae, pupae and total preoviposition period. The peak of age-specific fecundity in LC 15 and LC 25 treatment groups was lagged behind control group. Mean values of intrinsic rate of increase (r m ), net reproductive rate (R 0 ) and finite rate of increase (λ) observed from the LC 15 and LC 25 treatment groups were lower than those from the control group. But mean values of gross reproduction rate (GRR) was not different. The mean generation time (T) of the treatment groups was prolonged. Whether sublethal doses of metaflumizone could stimulate reproduction in the long term needs further investigation on continuous generations.
基金supported by the One Hundred Talents Program of Shanxi Province,China (201144)the Key Science and Technology Project of Shanxi Province,China (200903110300)
文摘Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth(DBM; Plutella xylostella). The trichoid sensilla were the most abundant sensory organ, and the male moth antennae host significantly more trichoid sensilla than female moth antennae. Conversely, basiconic and coeloconic sensilla were found more frequently on female than on male antennae. We performed experiments with various degrees of antennal ablation and demonstrated that DBM antennae played a key role in the control of mating and oviposition. We found that neither oviposition preference nor mating behaviors changed significantly when less than 1/4 of both antennae were removed. However, there was a significant behavioral change when the antennae were ablated by more than half. As the length of the antenna was shortened, the successful mating rate decreased and mating peak was delayed. An otherwise consistent host preference for oviposition was eliminated when both antennae were completely removed. Furthermore, we found that the number of trichoid sensilla was positively correlated with mating rate and oviposition preference. However, the numbers of basiconic and coeloconic sensilla were not correlated with mating rate and mating peak, but highly correlated with oviposition preference. Taken together, our results indicate that antennal sensory information plays a critical role in the mating and oviposition behaviors of this economically important pest.
基金supported by the National Natural Science Foundation of China (31230062 and 31321004)the Beijing Natural Science Foundation of China (6132028)the State Key Laboratory for Biology of Plant Diseases and Insect Pests, Chinese Academy of Agricultural Sciences (SKLOF201502)
文摘Strategies for insect population control are currently targeting chemical communication at the molecular level. The diamondback moth Plutella xylostella represents one of the most serious pests in agriculture, however detailed information on the proteins mediating olfaction in this species is still poor. This species is endowed with a repertoire of a large number of olfactory receptors and odorant binding proteins(OBPs). As a contribution to map the specificities of these chemical sensors in the moth and eventually unrave l the complexity of chemodetection, we have measured the affinities of three selected OBPs to a series of potential odorants. Three proteins are highly divergent in their amino acid sequences and show markedly different expression profiles. In fact, PxylOBP3 is exclusively expressed in the antennae of both sexes, PxylOBP9 is male specific and present only in antennae and reproductive organs, while PxylOBP19, an unusual OBP with nine cysteines, is ubiquitously present in all the organs examined. Such expression pattern suggests that the last two proteins may be involved in non-chemosensory functions. Despite such differences, the three OBPs exhibit similar binding spectra, together with high selectivity. Among the 26 natural compounds tested, only two proved to be good ligands, retinol and coniferyl aldehyde. This second compound is particularly interesting being part of the chemical pathway leading to regeneration of lignin, one of the defense strategies of the plant against insect attack, and might find applications as a repellent for P. xylostella and other pests.
基金the grants from the National Natural Science Foundation of China (39930120)
文摘With the bioguided fractionation of the ethanol extracts from the leaves of Momordica charantia, we obtained two most active compounds against the feeding of the diamondback moth, Plutella xylostella larvae. The antifeedant activity of momordicine I and momordicine II against the second and the third instar larvae of Plutella xylostella were tested using leaf discs of cabbage in the laboratory. The results showed that momordicin I and momordicin II had significant antifeedant activity on the larvae of P. xylostella, and momordicin II was more active than momordicin I. The concentrations for 50% antifeedant effects (AFC50) of momordicin II against the second and the third instar larvae of P. xylostella were 76.69 and 116.24 μg mL-1, whereas that of momordicin I was 144.08 and 168.42 μg mL-1, respectively. In addition, momordicin I and momordicin II had significant inhibitive effect on the rate of weight gain and survival of P. xylostella larvae.
文摘Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.
基金Supported by the Natural Science Foundation of Jilin Province,China(No.20060545)the International Cooperation Project of Changchun City,Jilin Province,China(No.2007GH28)
文摘The changes of the proteome in Arabidopsis thaliana leaves were examined by specialist Plutella xylostella.Analysis of about 1100 protein spots on each 2DE gel revealed 38 differentially expressed protein spots in abun-dance of which 34 proteins were identified by MALDI-TOF/TOF MS.Among the insect feeding responsive proteins,a few proteins involved in carbon metabolism were identified including proteins associated with the Calvin cycle in the chloroplast and TCA cycle in the mitochondria,indicating carbon metabolism related proteins may play crucial roles in induced defense response in plants under insect infestation.The analysis elucidates the subcellular location of proteins demonstrates that about 50% of proteins are in the chloroplast,which shows the chloroplast has a key role in the insect feeding response for plant.Gene expression analysis of 10 different proteins by quantitative real-time PCR shows that four proteins of the mRNA level were correlated well with the protein level.This study further dissected the nature of insect infestation as a stress signal and some novel insect feeding responsive proteins identified may play an important role in induced defence machanism for plant.
