The full-length sequence of the odorant binding protein 5 gene,HarmOBP5,was obtained from an antennae cDNA library of cotton bollworm,Helicoverpa armigera (Hübner).The cDNA contains a 444 bp open reading frame,...The full-length sequence of the odorant binding protein 5 gene,HarmOBP5,was obtained from an antennae cDNA library of cotton bollworm,Helicoverpa armigera (Hübner).The cDNA contains a 444 bp open reading frame,encoding a protein with 147 amino acids,namely HarmOBP5.HarmOBP5 was expressed in Escherichia coli and the recombinant protein was purified by affinity chromatography.SDS-PAGE and Western blot analysis demonstrated that the purified protein can be used for further investigation of its binding characteristics.Competitive binding assays with 113 odorant chemicals indicated that HarmOBP5 has strong affinity to some special plant volatiles,including (E)-β-farnesene,ethyl butyrate,ethyl heptanoate,and acetic acid 2-methylbutyl ester.Based on three-dimensional (3D) model of AaegOBP1 from Aedes aegypti,a 3D model of HarmOBP5 was predicted.The model revealed that some key binding residues in HarmOBP5 may play important roles in odorant perception of H.armigera.This study provides clues for better understanding physiological functions of OBPs in H.armigera and other insects.展开更多
Cry toxins produced by Bacillus thuringiensis(Bt) are effective biological insecticides against certain insect species.In this study,bioassay results indicated that Cry1B and Cry1C were toxic to Spodoptera exigua.We...Cry toxins produced by Bacillus thuringiensis(Bt) are effective biological insecticides against certain insect species.In this study,bioassay results indicated that Cry1B and Cry1C were toxic to Spodoptera exigua.We also identified a cadherin-like gene in S.exigua that could enhance the toxicity of Cry1B and Cry1C.The cadherin-like gene identified from the larvae midgut tissue was cloned by reverse transcription polymerase chain reaction(RT-PCR) and rapid amplification of cDNA ends(RACE).The full-length cDNA of the gene consisted of 5 220 bp encoding 1 740 amino acid with a predicted molecular mass of 196 kD.BLAST search analysis showed that the predicted amino acid sequence had a high sequence identity to the published sequences of cadherin-like proteins from other Lepidoptera insects.Spatial expression of the cadherin-like gene detected by qRT-PCR analysis revealed that the cadherin-like gene was mainly present in the gut of 4th instar larvae and during different life stages.The results suggested that the commercial development of this synergist has the potential to enhance Cry1B and Cry1C toxicity against Lepidoptera insects.展开更多
The scarab beetle, Anomala corpulenta Motschulsky(Coleoptera: Scarabaeoidea), is a widespread and destructive pest in China. Vision is one of the most important means of acquiring information about the external env...The scarab beetle, Anomala corpulenta Motschulsky(Coleoptera: Scarabaeoidea), is a widespread and destructive pest in China. Vision is one of the most important means of acquiring information about the external environment. In order to contribute to the understanding of the perception of visual stimuli in this species, the light sensitivity and spectral responses of the scarab beetle, A. corpulenta, were measured by using an electroretinogram(ERG) technique. In total, 14 monochromatic light intensities, between 340 and 605 nm, were applied to the compound eyes of A. corpulenta under varying levels of adaptation to dark and light conditions. The results showed that all light stimuli induced an ERG response, with varied amplitudes. The spectral sensitivity curve of dark-adapted eyes showed one major peak(~400 nm; near-ultraviolet), a secondary peak(from 498 to 562 nm; yellow-green) and the third peakat 460 nm. By contrast, in light-adapted eyes, only a near-UV peak was observed. From these results, we conclude that the compound eye of A. corpulenta is likely to have at least three spectral types of photoreceptor. Significance of differences were also recorded in the responses of male and female compound eyes, as well as diurnally and nocturnally. The amplitude of ERG in response to white-light stimuli varied with the light intensity: The stronger the luminance, the higher the ERG value. This suggests that the compound eye of A. corpulenta adapts quickly to changing light conditions, enabling A. corpulenta to maintain nocturnal activities.展开更多
A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera (Hvbner) was obtained from antennal eDNA libraries and expressed in Escherichia coll. The real time quantitative PCR (RT-qPCR) results ...A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera (Hvbner) was obtained from antennal eDNA libraries and expressed in Escherichia coll. The real time quantitative PCR (RT-qPCR) results indicated that HarmCSP5 gene was mainly expressed in male and female antennae but also expressed in female legs and wings. Competitive binding assays were performed to test the binding affinity of recombinant HarmCSP5 to 60 odor molecules including some cotton volatiles. The resules showed that HarmCSP5 showed strong binding abilities to 4-ehtylbenzaldehyde and 3,4-dimethlbenz aldehyde, whereas methyl phenylacetate, 2-decanone, 1-pentanol, carvenol, isobomeol, nerolidol, 2- nonanone and ethyl heptanoate have relatively weak binding affinity. Moreover, the predicted 3D model of HarmCSP5 consists of six α-helices located among residues 33-38 (αl), 40-48 (α2), 62-72 (α3), 80-96 (α4), 98-108 (α5), and 116-119 (α6), two pairs of disulfide bridges Cys49-Cys55, Cys75-Cys78. The two amino acid residues, Ile94 and Trpl01, may play crucial roles in HarmCSP5 binding with ligands and need further study for confirmation.展开更多
The effects of grape-tobacco intercropping patterns on populations of grape phylloxera, Daktulosphaira vitifoliae Fitch, as well as on the growth and development of the infested vines were evaluated in the field and t...The effects of grape-tobacco intercropping patterns on populations of grape phylloxera, Daktulosphaira vitifoliae Fitch, as well as on the growth and development of the infested vines were evaluated in the field and the impact of an aqueous tobacco root extract on grape phylloxera was evaluated using a laboratory bioassay. The aqueous tobacco root extract exhibited biological activity against this pest. The egg mortality, nymph mortality, development period, life span and female fecundity were significantly affected. In the field trial, grape phylloxera populations were clearly lower as compared to the monoculture pattern. However, the rates of newly developed roots and newly infested grape roots were significantly higher and lower, in intercropping patterns than in the vine monoculture, respectively. The grape phylloxera population number on the grape roots decreased each year, and the vine trees gradually renewed upon continuous intercropping with tobacco over three years. These results confirmed that intercropping grapes with tobacco can effectively control grape phylloxera in an infested vineyard. The results also indicated that additional crops could be intercropped with grapes and are effective against grape phylloxera, which should be explored as an integrated approach for controlling the pest.展开更多
Cry toxins produced by Bacillus thuringiensis (Bt) are effective biological insecticides against certain insect species. However, there are potential risks of the evolved resistance of insects to Cry toxin owing to ...Cry toxins produced by Bacillus thuringiensis (Bt) are effective biological insecticides against certain insect species. However, there are potential risks of the evolved resistance of insects to Cry toxin owing to decreased binding of toxins to target sites in the brush border membranes of the larva midgut. The Cry toxins with different binding sites in the larval midgut have been considered to be a good combination to deploy in delaying resistance evolution. Bioassay results demonstrated that the toxicity of different Cry toxins ranked differently for each species. The toxicity ranking was CrylAc〉CrylAb〉Cry2Ab for Helicoverpa armigera, CrylB〉CrylC〉Cry2Ab for Spodoptera exigua, and Cry2Ab〉CrylB〉 CrylC for S. litura. Only Cry2Ab was toxic to Agrotis ipsilon. Binding experiments were performed with ^125I-CrylAb, ^125I-CrylAc, ^125I-CrylB, ^125I-CrylC, ^125I-Cry2Ab and the brush border membranes vesicles (BBMV) from H. armigera, S. exigua, S. litura and A. ipsilon. The binding of CrylAb and CrylAc was shown to be saturable by incubating with increasing concentrations of H. armigera BBMV (Kd=(45.00+2.01) nmol L-1 and (12.80+0.18) nmol L^-1, respectively; Bmax=(54.95±l.79) ng and (55.44±0.91) ng, separately). The binding of CrylB was shown to be saturable by incubating with increasing concentrations ofS. exigua BBMV (Kd=(23.26±1.66) nmol L^-1; Bmax=(65.37±1.87) ng). The binding of ^125I-Cry toxins was shown to be non-saturable by incubating with increasing concentrations of S. litura and A. ipsilon BBMV. In contrast, CrylB and CrylC showed some combination with the BBMV orS. litura, and a certain amount of Cry2Ab could bind to the BBMV ofA. ipsilon. These observations suggest that a future strategy could be devised for the focused combination of specific cry genes in transgenic crops to control target pests, widen the spectrum of insecticide effectiveness and postpone insect resistance evolution.展开更多
A gene encoding a novel G protein β subunit of β1 subclass, GβMmed was isolated from Microplitis mediator (Hymenoptera: Braconidae). The full-length sequence of GβMmed is 1 119 bp, the cDNA contains a 1 023 bp...A gene encoding a novel G protein β subunit of β1 subclass, GβMmed was isolated from Microplitis mediator (Hymenoptera: Braconidae). The full-length sequence of GβMmed is 1 119 bp, the cDNA contains a 1 023 bp open reading frame that encodes a protein with 340 amino acids, and the predicted molecular weight of GβMmed is 37.23 kDa and isoelectric point is 5.86. By the quantitative real-time RT-PCR method, the tissue-specific expression and quantitative changes in the developmental expression profile of GβMmed were detected. It was found that GβMmed was abundantly expressed in M. mediator antennae, head (without antennae), thorax, abdomen, legs and the wings, and especially at high levels in abdomen. In antennae, expression varied through 1st day before emergence to 5-d-old adults, and had equal expression levels detected in females and males in total. In head, GβMmed expresses while initially high in females, and have another peaked in stage 4 and 1st day, in males showed a peak of GβMmed expression prior to emergence and relatively low levels after emergence. In female abdomen GβMmed expression levels have two peaks in stage 1 and the 5th d, but just have one peak in male abdomen in stage 1. In all other tissues expression was low and stable.展开更多
Carbohydrate chains are the principal antigens by which Bacillus thuringiensis(Bt) identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cells of i...Carbohydrate chains are the principal antigens by which Bacillus thuringiensis(Bt) identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cells of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cell surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modification of receptor proteins. It can indirectly influence the function of Bt. The 1 950 bp full-length c DNA encoding β-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques(GAL-Harm, Gen Bank accession no.: GQ904195.1) with two potential N-glycosylation sites(^157NNTI^160 and ^272NKTL^275). Protein sequence alignments revealed that H. armigera β-1,3-galactosyltransferase shared high identity with β-1,3-galactosyltransferase in other insect species. The expression level of the β-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function of β-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1 Ac enhanced the toxicity against the si RNA-treated larvae compared with non-si RNA-treated ones, which indicated β-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1 Ac in H. armigera.展开更多
Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner (Bt) have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain deba...Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner (Bt) have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain debate. The white-backed planthopper (WBPH), Sogatella furcifera (Horváth), is one of the most economically important insect pests of rice in Asian countries and also one of the main non-target herbivores of transgenic rice. In the current study, impacts of transgenic cry1Ab/vip3H+epsps rice (G6H1) with both insect and herbicide resistance on WBPH were evaluated to ascertain whether this transgenic rice line had potential risks for this sap-sucking pest under laboratory and ifeld conditions. The laboratory results showed that no signiifcant difference in egg developmental duration, nymphal survival rate and female fecundity was found for WBPH between G6H1 and its non-transgenic isoline (XS110). However, the development duration of nymphs was signiifcantly shorter and female longevity signiifcantly longer when WBPH fed on G6H1 by comparison with those on its control. To verify the results found in laboratory, a 3-yr ifeld trial was conducted to monitor WBPH population using both the vacuum-suction machine and beat plate methods. Although the seasonal density of WBPH nymphs and total density of nymphs and adults were not signiifcantly affected by transgenic rice regardless of the sampling methods, the seasonal density of WBPH adults in transgenic rice plots was slightly lower than that in the control when using the vacuum-suction machine. Based on these results both from laboratory and ifeld, it is clear that our tested transgenic rice line will not lead higher population of WBPH. However, long-term ifeld experiments to monitor the population dynamics of WPBH at large scale need to be conducted to conifrm the present conclusions in future.展开更多
With the long-term use of Bacillus thuringiensis (Bt) insecticide and expansion of CrylA-expressing transgenic plants, some insect pests have developed resistance to Bt in open fields, greenhouses, and in the labora...With the long-term use of Bacillus thuringiensis (Bt) insecticide and expansion of CrylA-expressing transgenic plants, some insect pests have developed resistance to Bt in open fields, greenhouses, and in the laboratory. Bt resistance is complex and there appear to be different ways for resistance development. Understanding the Bt resistance mechanisms is critical to prolong its usefulness. In this article, Bt receptors, the cadherin and aminopeptidase N (APN), in brush border membrane vesicles (/3BMV) of Helicoverpa armigera were examined in both CrylAc-susceptible (96S) and CrylAc- resistant (LF120) strains, to compare CrylAc toxin oligomerization and pore formation in these two strains. CrylAc toxin oligomerization and pore formation in these two strains were compared. Results showed that cadherin and aminopeptidase N proteins could express normally in both susceptible and resistant 11. armigera strains. The ability to form CrylAc oligomers and ion channels on BBMVs was also not significantly different between these two strains.展开更多
基金supported by the National Basic Research Program of China(2012CB114104)the National Natural Science Foundation of China(30871640,31071694)+1 种基金the National High-Tech R&D Program of China(2008AA02Z307)the International Cooperation and Exchange Foundation of NSFC-RS of China(31111130203).
文摘The full-length sequence of the odorant binding protein 5 gene,HarmOBP5,was obtained from an antennae cDNA library of cotton bollworm,Helicoverpa armigera (Hübner).The cDNA contains a 444 bp open reading frame,encoding a protein with 147 amino acids,namely HarmOBP5.HarmOBP5 was expressed in Escherichia coli and the recombinant protein was purified by affinity chromatography.SDS-PAGE and Western blot analysis demonstrated that the purified protein can be used for further investigation of its binding characteristics.Competitive binding assays with 113 odorant chemicals indicated that HarmOBP5 has strong affinity to some special plant volatiles,including (E)-β-farnesene,ethyl butyrate,ethyl heptanoate,and acetic acid 2-methylbutyl ester.Based on three-dimensional (3D) model of AaegOBP1 from Aedes aegypti,a 3D model of HarmOBP5 was predicted.The model revealed that some key binding residues in HarmOBP5 may play important roles in odorant perception of H.armigera.This study provides clues for better understanding physiological functions of OBPs in H.armigera and other insects.
基金supported by the National Basic Research Program of China(2012CB114104)the National Natural Science Foundation of China (31071694 and 31171858)
文摘Cry toxins produced by Bacillus thuringiensis(Bt) are effective biological insecticides against certain insect species.In this study,bioassay results indicated that Cry1B and Cry1C were toxic to Spodoptera exigua.We also identified a cadherin-like gene in S.exigua that could enhance the toxicity of Cry1B and Cry1C.The cadherin-like gene identified from the larvae midgut tissue was cloned by reverse transcription polymerase chain reaction(RT-PCR) and rapid amplification of cDNA ends(RACE).The full-length cDNA of the gene consisted of 5 220 bp encoding 1 740 amino acid with a predicted molecular mass of 196 kD.BLAST search analysis showed that the predicted amino acid sequence had a high sequence identity to the published sequences of cadherin-like proteins from other Lepidoptera insects.Spatial expression of the cadherin-like gene detected by qRT-PCR analysis revealed that the cadherin-like gene was mainly present in the gut of 4th instar larvae and during different life stages.The results suggested that the commercial development of this synergist has the potential to enhance Cry1B and Cry1C toxicity against Lepidoptera insects.
基金supported by the China Agricultural Research Stem (CARS-03)the Special Fund for Agro-Scientific Research in Public Interest,China (201003025)
文摘The scarab beetle, Anomala corpulenta Motschulsky(Coleoptera: Scarabaeoidea), is a widespread and destructive pest in China. Vision is one of the most important means of acquiring information about the external environment. In order to contribute to the understanding of the perception of visual stimuli in this species, the light sensitivity and spectral responses of the scarab beetle, A. corpulenta, were measured by using an electroretinogram(ERG) technique. In total, 14 monochromatic light intensities, between 340 and 605 nm, were applied to the compound eyes of A. corpulenta under varying levels of adaptation to dark and light conditions. The results showed that all light stimuli induced an ERG response, with varied amplitudes. The spectral sensitivity curve of dark-adapted eyes showed one major peak(~400 nm; near-ultraviolet), a secondary peak(from 498 to 562 nm; yellow-green) and the third peakat 460 nm. By contrast, in light-adapted eyes, only a near-UV peak was observed. From these results, we conclude that the compound eye of A. corpulenta is likely to have at least three spectral types of photoreceptor. Significance of differences were also recorded in the responses of male and female compound eyes, as well as diurnally and nocturnally. The amplitude of ERG in response to white-light stimuli varied with the light intensity: The stronger the luminance, the higher the ERG value. This suggests that the compound eye of A. corpulenta adapts quickly to changing light conditions, enabling A. corpulenta to maintain nocturnal activities.
基金supported by the National 973 Program of China (2012CB114104)the National Natural Science Foundation of China (31171858)
文摘A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera (Hvbner) was obtained from antennal eDNA libraries and expressed in Escherichia coll. The real time quantitative PCR (RT-qPCR) results indicated that HarmCSP5 gene was mainly expressed in male and female antennae but also expressed in female legs and wings. Competitive binding assays were performed to test the binding affinity of recombinant HarmCSP5 to 60 odor molecules including some cotton volatiles. The resules showed that HarmCSP5 showed strong binding abilities to 4-ehtylbenzaldehyde and 3,4-dimethlbenz aldehyde, whereas methyl phenylacetate, 2-decanone, 1-pentanol, carvenol, isobomeol, nerolidol, 2- nonanone and ethyl heptanoate have relatively weak binding affinity. Moreover, the predicted 3D model of HarmCSP5 consists of six α-helices located among residues 33-38 (αl), 40-48 (α2), 62-72 (α3), 80-96 (α4), 98-108 (α5), and 116-119 (α6), two pairs of disulfide bridges Cys49-Cys55, Cys75-Cys78. The two amino acid residues, Ile94 and Trpl01, may play crucial roles in HarmCSP5 binding with ligands and need further study for confirmation.
基金supported by the Project of National Technology System for Grape Industry (nycytx-30)
文摘The effects of grape-tobacco intercropping patterns on populations of grape phylloxera, Daktulosphaira vitifoliae Fitch, as well as on the growth and development of the infested vines were evaluated in the field and the impact of an aqueous tobacco root extract on grape phylloxera was evaluated using a laboratory bioassay. The aqueous tobacco root extract exhibited biological activity against this pest. The egg mortality, nymph mortality, development period, life span and female fecundity were significantly affected. In the field trial, grape phylloxera populations were clearly lower as compared to the monoculture pattern. However, the rates of newly developed roots and newly infested grape roots were significantly higher and lower, in intercropping patterns than in the vine monoculture, respectively. The grape phylloxera population number on the grape roots decreased each year, and the vine trees gradually renewed upon continuous intercropping with tobacco over three years. These results confirmed that intercropping grapes with tobacco can effectively control grape phylloxera in an infested vineyard. The results also indicated that additional crops could be intercropped with grapes and are effective against grape phylloxera, which should be explored as an integrated approach for controlling the pest.
基金supported by the Nationa l973 Program of China (2012CB114104)the National Natural Science Foundation of China (31071694, 31171858)the International Joint Project between China and UK of National Natural Science Foundation of China and RoyalSociety (31111130203)
文摘Cry toxins produced by Bacillus thuringiensis (Bt) are effective biological insecticides against certain insect species. However, there are potential risks of the evolved resistance of insects to Cry toxin owing to decreased binding of toxins to target sites in the brush border membranes of the larva midgut. The Cry toxins with different binding sites in the larval midgut have been considered to be a good combination to deploy in delaying resistance evolution. Bioassay results demonstrated that the toxicity of different Cry toxins ranked differently for each species. The toxicity ranking was CrylAc〉CrylAb〉Cry2Ab for Helicoverpa armigera, CrylB〉CrylC〉Cry2Ab for Spodoptera exigua, and Cry2Ab〉CrylB〉 CrylC for S. litura. Only Cry2Ab was toxic to Agrotis ipsilon. Binding experiments were performed with ^125I-CrylAb, ^125I-CrylAc, ^125I-CrylB, ^125I-CrylC, ^125I-Cry2Ab and the brush border membranes vesicles (BBMV) from H. armigera, S. exigua, S. litura and A. ipsilon. The binding of CrylAb and CrylAc was shown to be saturable by incubating with increasing concentrations of H. armigera BBMV (Kd=(45.00+2.01) nmol L-1 and (12.80+0.18) nmol L^-1, respectively; Bmax=(54.95±l.79) ng and (55.44±0.91) ng, separately). The binding of CrylB was shown to be saturable by incubating with increasing concentrations ofS. exigua BBMV (Kd=(23.26±1.66) nmol L^-1; Bmax=(65.37±1.87) ng). The binding of ^125I-Cry toxins was shown to be non-saturable by incubating with increasing concentrations of S. litura and A. ipsilon BBMV. In contrast, CrylB and CrylC showed some combination with the BBMV orS. litura, and a certain amount of Cry2Ab could bind to the BBMV ofA. ipsilon. These observations suggest that a future strategy could be devised for the focused combination of specific cry genes in transgenic crops to control target pests, widen the spectrum of insecticide effectiveness and postpone insect resistance evolution.
基金support from the Na-tional Natural Science Foundation of China (30871640,30330410)the National Basic Research Program ofChina (2007CB109202)the Research Foundationof State Key Laboratory for Biology of Plant Diseasesand Insect Pests of China (SKL2007SR01)
文摘A gene encoding a novel G protein β subunit of β1 subclass, GβMmed was isolated from Microplitis mediator (Hymenoptera: Braconidae). The full-length sequence of GβMmed is 1 119 bp, the cDNA contains a 1 023 bp open reading frame that encodes a protein with 340 amino acids, and the predicted molecular weight of GβMmed is 37.23 kDa and isoelectric point is 5.86. By the quantitative real-time RT-PCR method, the tissue-specific expression and quantitative changes in the developmental expression profile of GβMmed were detected. It was found that GβMmed was abundantly expressed in M. mediator antennae, head (without antennae), thorax, abdomen, legs and the wings, and especially at high levels in abdomen. In antennae, expression varied through 1st day before emergence to 5-d-old adults, and had equal expression levels detected in females and males in total. In head, GβMmed expresses while initially high in females, and have another peaked in stage 4 and 1st day, in males showed a peak of GβMmed expression prior to emergence and relatively low levels after emergence. In female abdomen GβMmed expression levels have two peaks in stage 1 and the 5th d, but just have one peak in male abdomen in stage 1. In all other tissues expression was low and stable.
基金supported by the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2012BAD19B05)the National Natural Science Foundation of China (30971921,31321004)
文摘Carbohydrate chains are the principal antigens by which Bacillus thuringiensis(Bt) identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cells of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cell surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modification of receptor proteins. It can indirectly influence the function of Bt. The 1 950 bp full-length c DNA encoding β-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques(GAL-Harm, Gen Bank accession no.: GQ904195.1) with two potential N-glycosylation sites(^157NNTI^160 and ^272NKTL^275). Protein sequence alignments revealed that H. armigera β-1,3-galactosyltransferase shared high identity with β-1,3-galactosyltransferase in other insect species. The expression level of the β-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function of β-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1 Ac enhanced the toxicity against the si RNA-treated larvae compared with non-si RNA-treated ones, which indicated β-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1 Ac in H. armigera.
基金provided by the Special Research Projects for Developing Transgenic Plants, China (2013ZX08011-001)China National Science Fund for Innovative Research Group of Biological Control (31021003)the National Basic Research Progarm of China (973 Program, 2007CB109202)
文摘Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner (Bt) have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain debate. The white-backed planthopper (WBPH), Sogatella furcifera (Horváth), is one of the most economically important insect pests of rice in Asian countries and also one of the main non-target herbivores of transgenic rice. In the current study, impacts of transgenic cry1Ab/vip3H+epsps rice (G6H1) with both insect and herbicide resistance on WBPH were evaluated to ascertain whether this transgenic rice line had potential risks for this sap-sucking pest under laboratory and ifeld conditions. The laboratory results showed that no signiifcant difference in egg developmental duration, nymphal survival rate and female fecundity was found for WBPH between G6H1 and its non-transgenic isoline (XS110). However, the development duration of nymphs was signiifcantly shorter and female longevity signiifcantly longer when WBPH fed on G6H1 by comparison with those on its control. To verify the results found in laboratory, a 3-yr ifeld trial was conducted to monitor WBPH population using both the vacuum-suction machine and beat plate methods. Although the seasonal density of WBPH nymphs and total density of nymphs and adults were not signiifcantly affected by transgenic rice regardless of the sampling methods, the seasonal density of WBPH adults in transgenic rice plots was slightly lower than that in the control when using the vacuum-suction machine. Based on these results both from laboratory and ifeld, it is clear that our tested transgenic rice line will not lead higher population of WBPH. However, long-term ifeld experiments to monitor the population dynamics of WPBH at large scale need to be conducted to conifrm the present conclusions in future.
基金supported by the National Basic Research Program of China (31071693)
文摘With the long-term use of Bacillus thuringiensis (Bt) insecticide and expansion of CrylA-expressing transgenic plants, some insect pests have developed resistance to Bt in open fields, greenhouses, and in the laboratory. Bt resistance is complex and there appear to be different ways for resistance development. Understanding the Bt resistance mechanisms is critical to prolong its usefulness. In this article, Bt receptors, the cadherin and aminopeptidase N (APN), in brush border membrane vesicles (/3BMV) of Helicoverpa armigera were examined in both CrylAc-susceptible (96S) and CrylAc- resistant (LF120) strains, to compare CrylAc toxin oligomerization and pore formation in these two strains. CrylAc toxin oligomerization and pore formation in these two strains were compared. Results showed that cadherin and aminopeptidase N proteins could express normally in both susceptible and resistant 11. armigera strains. The ability to form CrylAc oligomers and ion channels on BBMVs was also not significantly different between these two strains.