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Sample records for bt cry1ac protein

  1. Study on radioimmunoassay of Bt Cry1Ac protein

    International Nuclear Information System (INIS)

    Bt Cry1Ac protein was extracted from incubation of Bacillus thuringiensis HD-73, and cutting into more specific protein segment with high insect-resistance. High-affinity multi-colonial antibodies of Bt Cry1 Ac protein were obtained after injected it into New Zealand rabbits. By 125I labeling of Bt Cry1 Ac protein, a RIA kit was established. In this method, centrifuge for separation was not necessary due to the use of magnetic micro-particle and the specifications of the kit were found equal to those of imported ELISA. (authors)

  2. Acquisition of Cry1Ac protein by non-target arthropods in Bt soybean fields.

    Science.gov (United States)

    Yu, Huilin; Romeis, Jörg; Li, Yunhe; Li, Xiangju; Wu, Kongming

    2014-01-01

    Soybean tissue and arthropods were collected in Bt soybean fields in China at different times during the growing season to investigate the exposure of arthropods to the plant-produced Cry1Ac toxin and the transmission of the toxin within the food web. Samples from 52 arthropod species/taxa belonging to 42 families in 10 orders were analysed for their Cry1Ac content using enzyme-linked immunosorbent assay (ELISA). Among the 22 species/taxa for which three samples were analysed, toxin concentration was highest in the grasshopper Atractomorpha sinensis and represented about 50% of the concentration in soybean leaves. Other species/taxa did not contain detectable toxin or contained a concentration that was between 1 and 10% of that detected in leaves. These Cry1Ac-positive arthropods included a number of mesophyll-feeding Hemiptera, a cicadellid, a curculionid beetle and, among the predators, a thomisid spider and an unidentified predatory bug belonging to the Anthocoridae. Within an arthropod species/taxon, the Cry1Ac content sometimes varied between life stages (nymphs/larvae vs. adults) and sampling dates (before, during, and after flowering). Our study is the first to provide information on Cry1Ac-expression levels in soybean plants and Cry1Ac concentrations in non-target arthropods in Chinese soybean fields. The data will be useful for assessing the risk of non-target arthropod exposure to Cry1Ac in soybean.

  3. Acquisition of Cry1Ac protein by non-target arthropods in Bt soybean fields.

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    Huilin Yu

    Full Text Available Soybean tissue and arthropods were collected in Bt soybean fields in China at different times during the growing season to investigate the exposure of arthropods to the plant-produced Cry1Ac toxin and the transmission of the toxin within the food web. Samples from 52 arthropod species/taxa belonging to 42 families in 10 orders were analysed for their Cry1Ac content using enzyme-linked immunosorbent assay (ELISA. Among the 22 species/taxa for which three samples were analysed, toxin concentration was highest in the grasshopper Atractomorpha sinensis and represented about 50% of the concentration in soybean leaves. Other species/taxa did not contain detectable toxin or contained a concentration that was between 1 and 10% of that detected in leaves. These Cry1Ac-positive arthropods included a number of mesophyll-feeding Hemiptera, a cicadellid, a curculionid beetle and, among the predators, a thomisid spider and an unidentified predatory bug belonging to the Anthocoridae. Within an arthropod species/taxon, the Cry1Ac content sometimes varied between life stages (nymphs/larvae vs. adults and sampling dates (before, during, and after flowering. Our study is the first to provide information on Cry1Ac-expression levels in soybean plants and Cry1Ac concentrations in non-target arthropods in Chinese soybean fields. The data will be useful for assessing the risk of non-target arthropod exposure to Cry1Ac in soybean.

  4. Acquisition of Cry1Ac Protein by Non-Target Arthropods in Bt Soybean Fields

    OpenAIRE

    Huilin Yu; Jörg Romeis; Yunhe Li; Xiangju Li; Kongming Wu

    2014-01-01

    Soybean tissue and arthropods were collected in Bt soybean fields in China at different times during the growing season to investigate the exposure of arthropods to the plant-produced Cry1Ac toxin and the transmission of the toxin within the food web. Samples from 52 arthropod species/taxa belonging to 42 families in 10 orders were analysed for their Cry1Ac content using enzyme-linked immunosorbent assay (ELISA). Among the 22 species/taxa for which three samples were analysed, toxin concentra...

  5. Microarray detection and qPCR screening of potential biomarkers of Folsomia candida (Collembola: Isotomidae) exposed to Bt proteins (Cry1Ab and Cry1Ac)

    International Nuclear Information System (INIS)

    The impact of Bt proteins on non-target arthropods is less understood than their effects on target organisms where the mechanism of toxic action is known. Here, we report the effects of two Bt proteins, Cry1Ab and Cry1Ac, on gene expression in the non-target collembolan, Folsomia candida. A customized microarray was used to study gene expression in F. candida specimens that were exposed to Cry1Ab and Cry1Ac. All selected transcripts were subsequently confirmed by qPCR. Eleven transcripts were finally verified, and three of them were annotated. The responses of all eleven transcripts were tested in specimens for both Cry1Ab and Cry1Ac at a series of concentrations. These transcripts were separated into two and three groups for Cry1Ab and Cry1Ac, respectively, depend on their expression levels. However, those eleven transcripts did not respond to the Bt proteins in Bt-rice residues. -- Highlights: • We examined the effects of Bt proteins on gene expression of Folsomia candida. • Eleven transcripts were up-regulated by Bt proteins (Cry1Ab and Cry1Ac). • Only three of the eleven transcripts were annotated. • The responses of 11 transcripts were tested on both Cry1Ab and Cry1Ac. • These transcripts did not respond to the Bt proteins in Bt-rice residues. -- Eleven potential molecular biomarkers of Folsomia candida to Cry1Ab and Cry1Ac were screened by microarray and qPCR analysis

  6. Microarray detection and qPCR screening of potential biomarkers of Folsomia candida (Collembola: Isotomidae) exposed to Bt proteins (Cry1Ab and Cry1Ac)

    DEFF Research Database (Denmark)

    Yuan, Yiyang; Krogh, Paul Henning; Bai, Xue;

    2014-01-01

    The impact of Bt proteins on non-target arthropods is less understood than their effects on target organisms where the mechanism of toxic action is known. Here, we report the effects of two Bt proteins, Cry1Ab and Cry1Ac, on gene expression in the non-target collembolan, Folsomia candida...

  7. Microarray detection and qPCR screening of potential biomarkers of Folsomia candida (Collembola: Isotomidae) exposed to Bt proteins (Cry1Ab and Cry1Ac).

    Science.gov (United States)

    Yuan, Yiyang; Krogh, Paul Henning; Bai, Xue; Roelofs, Dick; Chen, Fajun; Zhu-Salzman, Keyan; Liang, Yuyong; Sun, Yucheng; Ge, Feng

    2014-01-01

    The impact of Bt proteins on non-target arthropods is less understood than their effects on target organisms where the mechanism of toxic action is known. Here, we report the effects of two Bt proteins, Cry1Ab and Cry1Ac, on gene expression in the non-target collembolan, Folsomia candida. A customized microarray was used to study gene expression in F. candida specimens that were exposed to Cry1Ab and Cry1Ac. All selected transcripts were subsequently confirmed by qPCR. Eleven transcripts were finally verified, and three of them were annotated. The responses of all eleven transcripts were tested in specimens for both Cry1Ab and Cry1Ac at a series of concentrations. These transcripts were separated into two and three groups for Cry1Ab and Cry1Ac, respectively, depend on their expression levels. However, those eleven transcripts did not respond to the Bt proteins in Bt-rice residues.

  8. No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae

    Directory of Open Access Journals (Sweden)

    Gabriela Vieira Silva

    2014-09-01

    Full Text Available No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae. Biological traits of the stink bug Euschistus heros and its main biological control agent Telenomus podisi were evaluated under controlled environmental conditions (25 ± 2ºC; 60 ± 10% RH; and 14/10 h photoperiod by placing first instar nymphs into Petri dishes with pods originating from two soybean isolines (Bt-soybean MON 87701 × MON 89788, which expresses the Cry1Ac protein, and its near non-Bt isoline A5547 where they remained until the adult stage. Due to gregarious behavior exhibited by first instar nymphs, they were individualized only when at the second instar. Adults were separated by sex and weighed, and pronotum width of each individual was subsequently measured. They were placed into plastic boxes containing soybean grains of the same soybean isoline as food source. Egg viability and female fecundity were assessed in adult individuals. Adult females of T. podisi (up to 24h old were placed with eggs of E. heros from mothers reared on both soybean isolines. Nymphal development time, insect weight, pronotum width, sex ratio, female fecundity, and egg viability (% emergence of Euschistus heros did not differ between treatments. Eggto-adult development time, female longevity, sex ratio, and percentage of parasitized eggs were not impacted by the Bt-soybean (expressing Cry1Ac protein. Results indicate that the Bt-soybean, MON 87701 × MON 89788, has no direct significant impact on the two studied species.

  9. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    International Nuclear Information System (INIS)

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants

  10. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, Sari J. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: sari.himanen@uku.fi; Nerg, Anne-Marja [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); Nissinen, Anne [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen (Finland); Stewart, C. Neal [University of Tennessee, Department of Plant Sciences, Knoxville, TN 37996-4561 (United States); Poppy, Guy M. [University of Southampton, School of Biological Sciences, Southampton SO16 7PX (United Kingdom); Holopainen, Jarmo K. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)

    2009-01-15

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants.

  11. Nematode diversity in soil from a field trial with decomposing Bt cotton expressing Cry1Ac and Cry2Ab2 protein

    Directory of Open Access Journals (Sweden)

    H. W. Karuri

    2013-10-01

    Full Text Available The quality of decomposing plant materials may affect the soil community structure. The aim of the study was to determine the impact of decomposing Bt cotton and its isoline on soil nematode diversity. Bt cotton (06Z604D, isoline (99M03 and HART 89M (local non-Bt cotton cultivar were planted for two seasons in a completely randomized block design in a confined field trial at Mwea, Kenya. After harvest the plant material was incorporated into soil and the nematode diversity was determined. The presence of Bt protein was evaluated using ELISA and insect bioassays. Abundance of bacteria feeding nematodes was significantly (p<0.05 high but to a smaller extent in the Bt cotton plots (53.7% and 52% in the first and second season respectively than in isoline (42.8% and 45% in the first and second season respectively. Insect bioassays detected Bt protein in the Bt cotton plots during the entire decomposition period in both seasons. There were no significant differences in nematode trophic groups composition between isoline and HART 89M. The effect of Cry2Ab2 and Cry1Ac protein in decomposing Bt cotton litter on soil nematodes was minimal. The study provides a basis for future studies on the impact of genetically engineered plants on soil nematodes in Kenyan agroecosystems.

  12. Activation of Bt Protoxin Cry1Ac in Resistant and Susceptible Cotton Bollworm.

    Directory of Open Access Journals (Sweden)

    Jizhen Wei

    Full Text Available Crystalline (Cry proteins from Bacillus thuringiensis (Bt are used extensively for insect control in sprays and transgenic plants, but their efficacy is reduced by evolution of resistance in pests. Here we evaluated reduced activation of Cry1Ac protoxin as a potential mechanism of resistance in the invasive pest Helicoverpa armigera. Based on the concentration killing 50% of larvae (LC50 for a laboratory-selected resistant strain (LF120 divided by the LC50 for its susceptible parent strain (LF, the resistance ratio was 1600 for Cry1Ac protoxin and 1200 for trypsin-activated Cry1Ac toxin. The high level of resistance to activated toxin as well as to protoxin indicates reduced activation of protoxin is not a major mechanism of resistance to Cry1Ac in LF120. For both insect strains, treatment with either the trypsin inhibitor N-a-tosyl-L-lysine chloromethyl ketone (TLCK or the chymotrypsin inhibitor N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK did not significantly affect the LC50 of Cry1Ac protoxin. Enzyme activity was higher for LF than LF120 for trypsin-like proteases, but did not differ between strains for chymotrypsin-like proteases. The results here are consistent with previous reports indicating that reduced activation of protoxin is generally not a major mechanism of resistance to Bt proteins.

  13. Activation of Bt Protoxin Cry1Ac in Resistant and Susceptible Cotton Bollworm.

    Science.gov (United States)

    Wei, Jizhen; Liang, Gemei; Wang, Bingjie; Zhong, Feng; Chen, Lin; Khaing, Myint Myint; Zhang, Jie; Guo, Yuyuan; Wu, Kongming; Tabashnik, Bruce E

    2016-01-01

    Crystalline (Cry) proteins from Bacillus thuringiensis (Bt) are used extensively for insect control in sprays and transgenic plants, but their efficacy is reduced by evolution of resistance in pests. Here we evaluated reduced activation of Cry1Ac protoxin as a potential mechanism of resistance in the invasive pest Helicoverpa armigera. Based on the concentration killing 50% of larvae (LC50) for a laboratory-selected resistant strain (LF120) divided by the LC50 for its susceptible parent strain (LF), the resistance ratio was 1600 for Cry1Ac protoxin and 1200 for trypsin-activated Cry1Ac toxin. The high level of resistance to activated toxin as well as to protoxin indicates reduced activation of protoxin is not a major mechanism of resistance to Cry1Ac in LF120. For both insect strains, treatment with either the trypsin inhibitor N-a-tosyl-L-lysine chloromethyl ketone (TLCK) or the chymotrypsin inhibitor N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK) did not significantly affect the LC50 of Cry1Ac protoxin. Enzyme activity was higher for LF than LF120 for trypsin-like proteases, but did not differ between strains for chymotrypsin-like proteases. The results here are consistent with previous reports indicating that reduced activation of protoxin is generally not a major mechanism of resistance to Bt proteins. PMID:27257885

  14. Increased frequency of pink bollworm resistance to Bt toxin Cry1Ac in China.

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    Peng Wan

    Full Text Available Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The main approach for delaying pest adaptation to Bt crops uses non-Bt host plants as "refuges" to increase survival of susceptible pests. To delay evolution of pest resistance to transgenic cotton producing Bt toxin Cry1Ac, the United States and some other countries have required refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. The "natural" refuge strategy focuses on cotton bollworm (Helicoverpa armigera, the primary target of Bt cotton in China that attacks many crops, but it does not apply to another major pest, pink bollworm (Pectinophora gossypiella, which feeds almost entirely on cotton in China. Here we report data showing field-evolved resistance to Cry1Ac by pink bollworm in the Yangtze River Valley of China. Laboratory bioassay data from 51 field-derived strains show that the susceptibility to Cry1Ac was significantly lower during 2008 to 2010 than 2005 to 2007. The percentage of field populations yielding one or more survivors at a diagnostic concentration of Cry1Ac increased from 0% in 2005-2007 to 56% in 2008-2010. However, the median survival at the diagnostic concentration was only 1.6% from 2008 to 2010 and failure of Bt cotton to control pink bollworm has not been reported in China. The early detection of resistance reported here may promote proactive countermeasures, such as a switch to transgenic cotton producing toxins distinct from Cry1A toxins, increased planting of non-Bt cotton, and integration of other management tactics together with Bt cotton.

  15. A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.

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    Wenbo Chen

    Full Text Available Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry proteins from the bacterium Bacillus thuringiensis (Bt in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50 of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects.

  16. A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.

    Science.gov (United States)

    Chen, Wenbo; Liu, Chenxi; Xiao, Yutao; Zhang, Dandan; Zhang, Yongdong; Li, Xianchun; Tabashnik, Bruce E; Wu, Kongming

    2015-01-01

    Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50) of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f) was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects. PMID:25885820

  17. A Toxin-Binding Alkaline Phosphatase Fragment Synergizes Bt Toxin Cry1Ac against Susceptible and Resistant Helicoverpa armigera

    OpenAIRE

    Wenbo Chen; Chenxi Liu; Yutao Xiao; Dandan Zhang; Yongdong Zhang; Xianchun Li; Bruce E Tabashnik; Kongming Wu

    2015-01-01

    Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50) of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase p...

  18. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem.

  19. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Zhuoya Zhao

    2016-07-01

    Full Text Available Crystal (Cry proteins derived from Bacillus thuringiensis (Bt have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem.

  20. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem. PMID:27399776

  1. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera

    Science.gov (United States)

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem. PMID:27399776

  2. Baseline susceptibility to Cry1Ac insecticidal protein in Heliothis virescens (Lepidoptera: Noctuidae) populations in Brazil.

    Science.gov (United States)

    Albernaz, K C; Merlin, B L; Martinelli, S; Head, G P; Omoto, C

    2013-08-01

    The tobacco budworm, Heliothis virescens (F.), is one of the target pests of genetically modified cotton expressing Cry1Ac insecticidal protein (Bt cotton) derived from Bacillus thuringiensis Berliner. This study was conducted to evaluate the susceptibility of field-collected populations of H. virescens to Cry1Ac to establish a baseline for use in an insect resistance management program for Bt cotton in Brazil. Insects were sampled from the main Brazilian cotton-growing regions (Bahia, Mato Grosso, Mato Grosso do Sul, and Goiás) during the cropping seasons of 2007/08 and 2008/09. Cry1Ac susceptibility was estimated by using diet incorporation bioassays. H. virescens was highly susceptible to Cry1Ac protein. The estimated LC50 values varied from 0.18 to 0.66 microg of Cry1Ac/ml of diet among the 2007-2008 populations (approximately 3.7-fold variation). Similarly, the EC50 values based on growth inhibition ranged from 0.0053 to 0.0161 microg of Cry1Ac/ml of diet for the 2007-2008 populations (approximately 3.0-fold variation). A joint analysis of the mortality data across all tested populations was used to develop and validate the diagnostic concentrations of 3.1 and 5.6 microg of Cry1Ac/ml of diet, the upper bound of the confidence interval and twice the LC99 were selected, for resistance monitoring programs of H. virescens to Cry1Ac protein in Brazil.

  3. Similar genetic basis of resistance to Bt toxin Cry1Ac in Boll-selected and diet-selected strains of pink bollworm.

    Directory of Open Access Journals (Sweden)

    Jeffrey A Fabrick

    Full Text Available Genetically engineered cotton and corn plants producing insecticidal Bacillus thuringiensis (Bt toxins kill some key insect pests. Yet, evolution of resistance by pests threatens long-term insect control by these transgenic Bt crops. We compared the genetic basis of resistance to Bt toxin Cry1Ac in two independently derived, laboratory-selected strains of a major cotton pest, the pink bollworm (Pectinophora gossypiella [Saunders]. The Arizona pooled resistant strain (AZP-R was started with pink bollworm from 10 field populations and selected with Cry1Ac in diet. The Bt4R resistant strain was started with a long-term susceptible laboratory strain and selected first with Bt cotton bolls and later with Cry1Ac in diet. Previous work showed that AZP-R had three recessive mutations (r1, r2, and r3 in the pink bollworm cadherin gene (PgCad1 linked with resistance to Cry1Ac and Bt cotton producing Cry1Ac. Here we report that inheritance of resistance to a diagnostic concentration of Cry1Ac was recessive in Bt4R. In interstrain complementation tests for allelism, F(1 progeny from crosses between AZP-R and Bt4R were resistant to Cry1Ac, indicating a shared resistance locus in the two strains. Molecular analysis of the Bt4R cadherin gene identified a novel 15-bp deletion (r4 predicted to cause the loss of five amino acids upstream of the Cry1Ac-binding region of the cadherin protein. Four recessive mutations in PgCad1 are now implicated in resistance in five different strains, showing that mutations in cadherin are the primary mechanism of resistance to Cry1Ac in laboratory-selected strains of pink bollworm from Arizona.

  4. Proteomics-based identification of midgut proteins correlated with Cry1Ac resistance in Plutella xylostella (L.).

    Science.gov (United States)

    Xia, Jixing; Guo, Zhaojiang; Yang, Zezhong; Zhu, Xun; Kang, Shi; Yang, Xin; Yang, Fengshan; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Xu, Weijun; Zhang, Youjun

    2016-09-01

    The diamondback moth, Plutella xylostella (L.), is a worldwide pest of cruciferous crops and can rapidly develop resistance to many chemical insecticides. Although insecticidal crystal proteins (i.e., Cry and Cyt toxins) derived from Bacillus thuringiensis (Bt) have been useful alternatives to chemical insecticides for the control of P. xylostella, resistance to Bt in field populations of P. xylostella has already been reported. A better understanding of the resistance mechanisms to Bt should be valuable in delaying resistance development. In this study, the mechanisms underlying P. xylostella resistance to Bt Cry1Ac toxin were investigated using two-dimensional differential in-gel electrophoresis (2D-DIGE) and ligand blotting for the first time. Comparative analyses of the constitutive expression of midgut proteins in Cry1Ac-susceptible and -resistant P. xylostella larvae revealed 31 differentially expressed proteins, 21 of which were identified by mass spectrometry. Of these identified proteins, the following fell into diverse eukaryotic orthologous group (KOG) subcategories may be involved in Cry1Ac resistance in P. xylostella: ATP-binding cassette (ABC) transporter subfamily G member 4 (ABCG4), trypsin, heat shock protein 70 (HSP70), vacuolar H(+)-ATPase, actin, glycosylphosphatidylinositol anchor attachment 1 protein (GAA1) and solute carrier family 30 member 1 (SLC30A1). Additionally, ligand blotting identified the following midgut proteins as Cry1Ac-binding proteins in Cry1Ac-susceptible P. xylostella larvae: ABC transporter subfamily C member 1 (ABCC1), solute carrier family 36 member 1 (SLC36A1), NADH dehydrogenase iron-sulfur protein 3 (NDUFS3), prohibitin and Rap1 GTPase-activating protein 1. Collectively, these proteomic results increase our understanding of the molecular resistance mechanisms to Bt Cry1Ac toxin in P. xylostella and also demonstrate that resistance to Bt Cry1Ac toxin is complex and multifaceted. PMID:27521921

  5. Ingestion of Bt corn pollen containing Cry1Ab/2Aj or Cry1Ac does not harm Propylea japonica larvae

    OpenAIRE

    Yanmin Liu; Qingsong Liu; Yanan Wang; Xiuping Chen; Xinyuan Song; Jörg Romeis; Yunhe Li; Yufa Peng

    2016-01-01

    Propylea japonica (Thunberg) (Coleoptera: Coccinellidae) is a prevalent pollen consumer in corn fields and is therefore exposed to insecticidal proteins contained in the pollen of insect-resistant transgenic corn cultivars expressing Cry proteins derived from Bacillus thuringiensis (Bt). In the present study, the potential effect of Cry1Ab/2Aj- or Cry1Ac-containing transgenic Bt corn pollen on the fitness of P. japonica larvae was evaluated. The results show that the larval developmental time...

  6. Functional validation of cadherin as a receptor of Bt toxin Cry1Ac in Helicoverpa armigera utilizing the CRISPR/Cas9 system.

    Science.gov (United States)

    Wang, Jing; Zhang, Haonan; Wang, Huidong; Zhao, Shan; Zuo, Yayun; Yang, Yihua; Wu, Yidong

    2016-09-01

    Cadherins have been identified as receptors of Bacillus thuringiensis (Bt) Cry1A toxins in several lepidopteran insects including the cotton bollworm, Helicoverpa armigera. Disruption of the cadherin gene HaCad has been genetically linked to resistance to Bt toxin Cry1Ac in H. armigera. By using the CRISPR/Cas9 genome editing system (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9), HaCad from the Cry1Ac-susceptible SCD strain of H. armigera was successfully knocked out. A single positive CRISPR event with a frame shift deletion of 4 nucleotides was identified and made homozygous to create a knockout line named SCD-Cad. Western blotting confirmed that HaCad was no longer expressed in the SCD-Cad line while an intact HaCad of 210 kDa was present in the parental SCD strain. Insecticide bioassays were used to show that SCD-Cad exhibited 549-fold resistance to Cry1Ac compared with SCD, but no significant change in susceptibility to Cry2Ab. Our results not only provide strong reverse genetics evidence for HaCad as a functional receptor of Cry1Ac, but also demonstrate that the CRISPR/Cas9 technique can act as a powerful and efficient genome editing tool to study gene function in a global agricultural pest, H. armigera.

  7. The cultivation of Bt corn producing Cry1Ac toxins does not adversely affect non-target arthropods.

    Science.gov (United States)

    Guo, Yanyan; Feng, Yanjie; Ge, Yang; Tetreau, Guillaume; Chen, Xiaowen; Dong, Xuehui; Shi, Wangpeng

    2014-01-01

    Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt) provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée), and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs) is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure of NTAs. On each sampling date, the total abundance, Shannon's diversity index, Pielou's evenness index and Simpson's diversity index were not significantly affected by Bt corn as compared to non-Bt corn. The "sampling dates" had a significant effect on these indices, but no clear tendencies related to "Bt corn" or "sampling dates X corn variety" interaction were recorded. Principal response curve analysis of variance indicated that Bt corn did not alter the distribution of NTAs communities. Bray-Curtis dissimilarity and distance analysis showed that Cry1Ac toxin exposure did not increase community dissimilarities between Bt and non-Bt corn plots and that the evolution of non-target arthropod community was similar on the two corn varieties. The cultivation of Bt corn failed to show any detrimental evidence on the density of non-target herbivores, predators and parasitoids. The composition of herbivores, predators and parasitoids was identical in Bt and non-Bt corn plots. Taken together, results from the present work support that Bt corn producing Cry1Ac toxins does not adversely affect NTAs.

  8. The Cultivation of Bt Corn Producing Cry1Ac Toxins Does Not Adversely Affect Non-Target Arthropods

    OpenAIRE

    Yanyan Guo; Yanjie Feng; Yang Ge; Guillaume Tetreau; Xiaowen Chen; Xuehui Dong; Wangpeng Shi

    2014-01-01

    Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt) provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée), and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs) is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure o...

  9. High Susceptibility to Cry1Ac and Low Resistance Allele Frequency Reduce the Risk of Resistance of Helicoverpa armigers to Bt Soybean in Brazil.

    Science.gov (United States)

    Dourado, Patrick M; Bacalhau, Fabiana B; Amado, Douglas; Carvalho, Renato A; Martinelli, Samuel; Head, Graham P; Omoto, Celso

    2016-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), was recently introduced into Brazil, where it has caused extensive damage to cotton and soybean crops. MON 87701 × MON 89788 soybean, which expresses the Bt protein Cry1Ac, was recently deployed in Brazil, providing high levels of control against H. armigera. To assess the risk of resistance to the Cry1Ac protein expressed by MON 87701 × MON 89788 soybean in Brazil, we conducted studies to evaluate the baseline susceptibility of H. armigera to Cry1Ac, in planta efficacy including the assessment of the high-dose criterion, and the initial resistance allele frequency based on an F2 screen. The mean Cry1Ac lethal concentration (LC50) ranged from 0.11 to 1.82 μg·mL-1 of diet among all H. armigera field populations collected from crop seasons 2013/14 to 2014/15, which indicated about 16.5-fold variation. MON 87701 × MON 89788 soybean exhibited a high level of efficacy against H. armigera and most likely met the high dose criterion against this target species in leaf tissue dilution bioassays up to 50 times. A total of 212 F2 family lines of H. armigera were established from field collections sampled from seven locations across Brazil and were screened for the presence of MON 87701 × MON 89788 soybean resistance alleles. None of the 212 families survived on MON 87701 × MON 89788 soybean leaf tissue (estimated allele frequency = 0.0011). The responses of H. armigera to Cry1Ac protein, high susceptibility to MON 87701 × MON 89788 soybean, and low frequency of resistance alleles across the main soybean-producing regions support the assumptions of a high-dose/refuge strategy. However, maintenance of reasonable compliance with the refuge recommendation will be essential to delay the evolution of resistance in H. armigera to MON 87701 × MON 89788 soybean in Brazil. PMID:27532632

  10. High Susceptibility to Cry1Ac and Low Resistance Allele Frequency Reduce the Risk of Resistance of Helicoverpa armigera to Bt Soybean in Brazil

    Science.gov (United States)

    Bacalhau, Fabiana B.; Amado, Douglas; Carvalho, Renato A.; Martinelli, Samuel; Head, Graham P.; Omoto, Celso

    2016-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), was recently introduced into Brazil, where it has caused extensive damage to cotton and soybean crops. MON 87701 × MON 89788 soybean, which expresses the Bt protein Cry1Ac, was recently deployed in Brazil, providing high levels of control against H. armigera. To assess the risk of resistance to the Cry1Ac protein expressed by MON 87701 × MON 89788 soybean in Brazil, we conducted studies to evaluate the baseline susceptibility of H. armigera to Cry1Ac, in planta efficacy including the assessment of the high-dose criterion, and the initial resistance allele frequency based on an F2 screen. The mean Cry1Ac lethal concentration (LC50) ranged from 0.11 to 1.82 μg·mL−1 of diet among all H. armigera field populations collected from crop seasons 2013/14 to 2014/15, which indicated about 16.5-fold variation. MON 87701 × MON 89788 soybean exhibited a high level of efficacy against H. armigera and most likely met the high dose criterion against this target species in leaf tissue dilution bioassays up to 50 times. A total of 212 F2 family lines of H. armigera were established from field collections sampled from seven locations across Brazil and were screened for the presence of MON 87701 × MON 89788 soybean resistance alleles. None of the 212 families survived on MON 87701 × MON 89788 soybean leaf tissue (estimated allele frequency = 0.0011). The responses of H. armigera to Cry1Ac protein, high susceptibility to MON 87701 × MON 89788 soybean, and low frequency of resistance alleles across the main soybean-producing regions support the assumptions of a high-dose/refuge strategy. However, maintenance of reasonable compliance with the refuge recommendation will be essential to delay the evolution of resistance in H. armigera to MON 87701 × MON 89788 soybean in Brazil. PMID:27532632

  11. [Comparison between transgenic insect-resistant cotton expressing Cry1Ac protein and its parental variety in rhizospheric fungal diversity].

    Science.gov (United States)

    Pan, Jian-Gang; Jiao, Hai-Hua; Bai, Zhi-Hui; Qi, Hong-Yan; Ma, An-Zhou; Zhuang, Guo-qiang; Zhang, Hong-xun

    2014-11-01

    The dynamics of rhizospheric fungal diversity and biomass at different sampling stages associated with two transgenic insectresistant cottons expressing Cry1Ac protein and their control varieties were studied under greenhouse conditions, followed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time polymerase chain reaction (Q-PCR), in order to evaluate the ecological security of planting transgenic cotton expressing Cry1Ac protein. The results indicated that the fungal superior bands in rhizosphere of transgenic Bt cotton were similar with that of control cotton at four sampling stages, the more obvious difference in the blurred bands among transgenic Bt cotton, JM20 and SHIYUAN321 was detected. The rhizospheric fungal biomass of transgenic Bt cotton SGK321 was significantly lower than that of its parental control cotton at seedling stage, while the slight decrease in fungal biomass of transgenic Bt cotton XP188 was detected at boll forming stage, the ill-defined decrease, even growing tendency in two transgenic Bt cottons was detected at other stages. However, the difference of rhizospheric fungal community compositions and biomass was not only existed between transgenic cotton and its control, but also between SHIYUAN321 and JM20, and the same phenomenon was also detected between transgenic Bt cotton SGK321 and XP188. Hence, Bt protein is not the only incentive resulting in the difference in fungal community composition and diversity, the decrease in biomass between transgenic cotton and untransgenic cotton, different cotton varieties has an effect on them. PMID:25639113

  12. The cultivation of Bt corn producing Cry1Ac toxins does not adversely affect non-target arthropods.

    Science.gov (United States)

    Guo, Yanyan; Feng, Yanjie; Ge, Yang; Tetreau, Guillaume; Chen, Xiaowen; Dong, Xuehui; Shi, Wangpeng

    2014-01-01

    Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt) provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée), and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs) is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure of NTAs. On each sampling date, the total abundance, Shannon's diversity index, Pielou's evenness index and Simpson's diversity index were not significantly affected by Bt corn as compared to non-Bt corn. The "sampling dates" had a significant effect on these indices, but no clear tendencies related to "Bt corn" or "sampling dates X corn variety" interaction were recorded. Principal response curve analysis of variance indicated that Bt corn did not alter the distribution of NTAs communities. Bray-Curtis dissimilarity and distance analysis showed that Cry1Ac toxin exposure did not increase community dissimilarities between Bt and non-Bt corn plots and that the evolution of non-target arthropod community was similar on the two corn varieties. The cultivation of Bt corn failed to show any detrimental evidence on the density of non-target herbivores, predators and parasitoids. The composition of herbivores, predators and parasitoids was identical in Bt and non-Bt corn plots. Taken together, results from the present work support that Bt corn producing Cry1Ac toxins does not adversely affect NTAs. PMID:25437213

  13. The cultivation of Bt corn producing Cry1Ac toxins does not adversely affect non-target arthropods.

    Directory of Open Access Journals (Sweden)

    Yanyan Guo

    Full Text Available Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée, and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure of NTAs. On each sampling date, the total abundance, Shannon's diversity index, Pielou's evenness index and Simpson's diversity index were not significantly affected by Bt corn as compared to non-Bt corn. The "sampling dates" had a significant effect on these indices, but no clear tendencies related to "Bt corn" or "sampling dates X corn variety" interaction were recorded. Principal response curve analysis of variance indicated that Bt corn did not alter the distribution of NTAs communities. Bray-Curtis dissimilarity and distance analysis showed that Cry1Ac toxin exposure did not increase community dissimilarities between Bt and non-Bt corn plots and that the evolution of non-target arthropod community was similar on the two corn varieties. The cultivation of Bt corn failed to show any detrimental evidence on the density of non-target herbivores, predators and parasitoids. The composition of herbivores, predators and parasitoids was identical in Bt and non-Bt corn plots. Taken together, results from the present work support that Bt corn producing Cry1Ac toxins does not adversely affect NTAs.

  14. Quantification of Cry1Ac protein at different stages of plant growth in cotton (Gossypium hirsutum L.

    Directory of Open Access Journals (Sweden)

    Muhammad Idrees Khan

    2012-12-01

    Full Text Available The present study was conducted at Central Cotton Research Institute, Multan, Pakistan during cotton growing season 2009-10. Nine cotton cultivars with Cry 1 Ac gene (Mon 531 event selected for current experiment to characterize the toxin level of Cry1Ac protein in different Bt cotton cultivars and to record the variation in Cry1Ac protein at various plant growth stages. It was found that age of plant was having an influence on the expression of gene. Maximum level of endotoxin (0.373g/g was observed in genotype CIM-595 at 100 days of planting. While minimum value (0.166g/g was observed in genotype V-1 at 160 days of planting. Similarly different cotton genotypes showed different boll worm damage % at different growth stages. CEMB-2 was found to be most susceptible genotype showing 93.33 % boll worm damage at 160 days after planting. While V-5 proved to be most resistant showing no boll worm damage at 70 and 100 days after planting.

  15. A comprehensive assessment of the effects of Bt cotton on Coleomegilla maculata demonstrates no detrimental effects by Cry1Ac and Cry2Ab.

    Directory of Open Access Journals (Sweden)

    Yunhe Li

    Full Text Available The ladybird beetle, Coleomegilla maculata (DeGeer, is a common and abundant predator in many cropping systems. Its larvae and adults are predaceous, feeding on aphids, thrips, lepidopteran larvae and plant tissues, such as pollen. Therefore, this species is exposed to insecticidal proteins expressed in insect-resistant, genetically engineered cotton expressing Cry proteins derived from Bacillus thuringiensis (Bt. A tritrophic bioassay was conduced to evaluate the potential impact of Cry2Ab- and Cry1Ac-expressing cotton on fitness parameters of C. maculata using Bt-susceptible and -resistant larvae of Trichoplusia ni as prey. Coleomegilla maculata survival, development time, adult weight and fecundity were not different when they were fed with resistant T. ni larvae reared on either Bt or control cotton. To ensure that C. maculata were not sensitive to the tested Cry toxins independent from the plant background and to add certainty to the hazard assessment, C. maculata larvae were fed artificial diet incorporated with Cry2Ab, Cry1Ac or both at >10 times higher concentrations than in cotton tissue. Artificial diet containing E-64 was included as a positive control. No differences were detected in any life-table parameters between Cry protein-containing diet treatments and the control diet. In contrast, larvae of C. maculata fed the E-64 could not develop to the pupal stage and the 7-d larval weight was significantly negatively affected. In both feeding assays, the stability and bioactivity of Cry proteins in the food sources were confirmed by ELISA and sensitive-insect bioassays. Our results show that C. maculata is not affected by Bt cotton and is not sensitive to Cry2Ab and Cry1Ac at concentrations exceeding the levels in Bt cotton, thus demonstrating that Bt cotton will pose a negligible risk to C. maculata. More importantly, this study demonstrates a comprehensive system for assessing the risk of genetically modified plants on non

  16. Ingestion of Bt corn pollen containing Cry1Ab/2Aj or Cry1Ac does not harm Propylea japonica larvae.

    Science.gov (United States)

    Liu, Yanmin; Liu, Qingsong; Wang, Yanan; Chen, Xiuping; Song, Xinyuan; Romeis, Jörg; Li, Yunhe; Peng, Yufa

    2016-01-01

    Propylea japonica (Thunberg) (Coleoptera: Coccinellidae) is a prevalent pollen consumer in corn fields and is therefore exposed to insecticidal proteins contained in the pollen of insect-resistant transgenic corn cultivars expressing Cry proteins derived from Bacillus thuringiensis (Bt). In the present study, the potential effect of Cry1Ab/2Aj- or Cry1Ac-containing transgenic Bt corn pollen on the fitness of P. japonica larvae was evaluated. The results show that the larval developmental time was significantly shorter when P. japonica larvae were fed pollen from Bt corn cultivars rather than control pollen but that pupation rate, eclosion rate, and adult fresh weight were not significantly affected. In the feeding experiments, the stability of the Cry proteins in the food sources was confirmed. When Bt corn pollen passed through the gut of P. japonica, 23% of Cry1Ab/2Aj was digested. The results demonstrate that consumption of Bt corn pollen containing Cry1Ab/2Aj or Cry1Ac has no detrimental effect on P. japonica larvae; the shortened developmental time of larvae that consumed these proteins was likely attributable to unknown differences in the nutritional composition between the Bt-transgenic and control corn pollen. PMID:27005950

  17. Field Performance of Bt Eggplants (Solanum melongena L.) in the Philippines: Cry1Ac Expression and Control of the Eggplant Fruit and Shoot Borer (Leucinodes orbonalis Guenée)

    Science.gov (United States)

    Hautea, Desiree M.; Taylo, Lourdes D.; Masanga, Anna Pauleen L.; Sison, Maria Luz J.; Narciso, Josefina O.; Quilloy, Reynaldo B.; Hautea, Randy A.; Shotkoski, Frank A.; Shelton, Anthony M.

    2016-01-01

    Plants expressing Cry proteins from the bacterium, Bacillus thuringiensis (Bt), have become a major tactic for controlling insect pests in maize and cotton globally. However, there are few Bt vegetable crops. Eggplant (Solanum melongena) is a popular vegetable grown throughout Asia that is heavily treated with insecticides to control the eggplant fruit and shoot borer, Leucinodes orbonalis (EFSB). Herein we provide the first publicly available data on field performance in Asia of eggplant engineered to produce the Cry1Ac protein. Replicated field trials with five Bt eggplant open-pollinated (OP) lines from transformation event EE-1 and their non-Bt comparators were conducted over three cropping seasons in the Philippines from 2010–2012. Field trials documented levels of Cry1Ac protein expressed in plants and evaluated their efficacy against the primary target pest, EFSB. Cry1Ac concentrations ranged from 0.75–24.7 ppm dry weight with the highest in the terminal leaves (or shoots) and the lowest in the roots. Cry1Ac levels significantly increased from the vegetative to the reproductive stage. Bt eggplant lines demonstrated excellent control of EFSB. Pairwise analysis of means detected highly significant differences between Bt eggplant lines and their non-Bt comparators for all field efficacy parameters tested. Bt eggplant lines demonstrated high levels of control of EFSB shoot damage (98.6–100%) and fruit damage (98.1–99.7%) and reduced EFSB larval infestation (95.8–99.3%) under the most severe pest pressure during trial 2. Moths that emerged from larvae collected from Bt plants in the field and reared in their Bt eggplant hosts did not produce viable eggs or offspring. These results demonstrate that Bt eggplant lines containing Cry1Ac event EE-1 provide outstanding control of EFSB and can dramatically reduce the need for conventional insecticides. PMID:27322533

  18. Identification of an alkaline phosphatase as a putative Cry1Ac binding protein in Ostrinia furnacalis (Guenée).

    Science.gov (United States)

    Jin, Tingting; Duan, Xiaoli; Bravo, Alejandra; Soberón, Mario; Wang, Zhenying; He, Kanglai

    2016-07-01

    Asian corn borer (ACB), Ostrinia furnacalis, is an important insect pest of maize susceptible to different Cry1A toxins. Based on amino acid sequence alignment of ALP sequences from lepidopteran larvae an alp gene was cloned from ACB, named ofalp. Pull dawn assays using biotinylated Cry1Ac and brush border membrane vesicles isolated from second instar ACB larvae showed that four proteins of 50, 65, 68 and 70kDa precipitated with the Cry1Ac. The 65kDa band cross-reacted with the anti-OfALP monoclonal antibody. GalNac was able to release the binding of Cry1Ac to the 65kDa OfALP in pull down assays. A 37kDa fragment from residues D173 to D473 of OfALP was cloned and expressed in Escherichia coli cells. We show that this ALP-fragment was able to bind Cry1Ac in ligand blot analysis. Our data also indicate that different ALP isoforms or variants may be also Cry1Ac binding proteins since more ALP enzymatic activity was pull down with Cry1Ac than with anti-OfALP antibody. We also analyzed the expression levels of ALP throughout the larval development by qPCR and ALP enzymatic activity. Our data indicated that ALP expression in ACB was observed preferentially in young instar larvae. Finally, we show that resistance in O. furnacalis ACB-AcR strain resistant to Cry1Ac did not correlate with changes in expression of this ALP protein since it shows similar gene expression of ofalp than the susceptible insect strain. Identification of Cry1Ac receptors will help to understand mechanism of action of Cry1Ac in O. furnacalis and to understand mechanism of Cry toxin resistance. Our data indicate that at least one ALP protein is involved in the binding interaction with Cry1Ac in O. furnacalis. PMID:27265829

  19. Detrimental effect of expression ofBt endotoxin Cry1Ac on in vitro regeneration, in vivo growth and development of tobacco and cotton transgenics

    Indian Academy of Sciences (India)

    Preeti Rawat; Amarjeet Kumar Singh; Krishna Ray; Bhupendra Chaudhary; Sanjeev Kumar; Taru Gautam; Shaveta Kanoria; Gurpreet Kaur; Paritosh Kumar; Deepak Pental; Pradeep Kumar Burma

    2011-06-01

    High levels of expression of the cry1Ac gene from Bacillus thuringiensis cannot be routinely achieved in transgenic plants despite modifications made in the gene to improve its expression. This has been attributed to the instability of the transcript in a few reports. In the present study, based on the genetic transformation of cotton and tobacco, we show that the expression of the Cry1Ac endotoxin has detrimental effects on both the in vitro and in vivo growth and development of transgenic plants. A number of experiments on developing transgenics in cotton with different versions of cry1Ac gene showed that the majority of the plants did not express any Cry1Ac protein. Based on Southern blot analysis, it was also observed that a substantial number of lines did not contain the cry1Ac gene cassette although they contained the marker gene nptII. More significantly, all the lines that showed appreciable levels of expression were found to be phenotypically abnormal. Experiments on transformation of tobacco with different constructs expressing the cry1Ac gene showed that in vitro regeneration was inhibited by the encoded protein. Further, out of a total of 145 independent events generated with the different cry1Ac gene constructs in tobacco, only 21 showed expression of the Cry1Ac protein, confirming observations made in cotton that regenerants that express high levels of the Cry1Ac protein are selected against during regeneration of transformed events. This problem was circumvented by targeting the Cry1Ac protein to the chloroplast, which also significantly improved the expression of the protein.

  20. A cadherin-like protein functions as a receptor for Bacillus thuringiensis Cry1Aa and Cry1Ac toxins on midgut epithelial cells of Bombyx mori larvae.

    Science.gov (United States)

    Hara, Hirotaka; Atsumi, Shogo; Yaoi, Katsuro; Nakanishi, Kazuko; Higurashi, Satoshi; Miura, Nami; Tabunoki, Hiroko; Sato, Ryoichi

    2003-03-13

    Aminopeptidase N (APN) and cadherin-like protein (BtR175) from Bombyx mori larvae were examined for their roles in Cry1Aa- and Cry1Ac-induced lysis of B. mori midgut epithelial cells (MECs). APNs and BtR175 were present in all areas of the midgut, were particularly abundant in the posterior region, and were found only on columnar cell microvilli and not on the lateral membrane that makes cell-cell contacts. This distribution was in accordance with the distribution of Cry1A-susceptible MECs in the midgut. The lytic activity of Cry1Aa and Cry1Ac on collagenase-dissociated MECs was linearly dependent on toxin concentration. Although pre-treatment of MECs with anti-BtR175 antibody was observed to partially inhibit the lytic activity exerted by 0.1-1 nM Cry1Aa toxin or 5 nM Cry1Ac toxin, no significant inhibition was observed when MECs were pre-treated with anti-APN antibody. These results suggest that BtR175 functions as a major receptor for Cry1A toxins in the midgut of B. mori larvae. PMID:12633848

  1. High Sensitivity Bacillus thuringiensis Cry1Ac Protein Detections Using Fluorescein Diacetate Nanoparticles.

    Science.gov (United States)

    Liu, Cui; Zhou, Zhen; Zou, Linling; Cao, Yuan-Cheng; Liu, Jun'An; Lin, Yongjun

    2016-03-01

    A highly sensitive transgenic protein analysis method was proposed here based on fluorescein diacetate (FDA). First, FDA was prepared by the ball mill to harvest the nano-sized organic particles. Further examines showed that the FDA size can be controlled by the speed of centrifugation which can obtain FDA in well-distributed size. Cy3 antibody immobilization tests showed that the proteins can attach onto the FDA particles while keep bioactivities. FDA and Cry1Ac antibody immunoassay tests showed that when the FDA particle was in 150 nm, the linear range was 0.01 ng/L-30 μg/mL. And it has the lower detection limitation of 0.01 ng/L, which is 100 times more sensitive than the ELISA methods. These results indicate that the FDA related immunoassays are the promising approach in the transgenic analysis.

  2. Studies on resistance mechanism of Bombyx mori against Bacillus thuringiensis insecticidal Cry1Ac toxin-Role of Cry1Ac binding proteins localizing on peritrophic and epithelial cell membranes of midgut-

    OpenAIRE

    Shitomi, Yasuyuki; 蔀, 泰幸

    2006-01-01

    Bombyx mori, hybrid Shunrei x Shogetsu, is susceptible to Cry1Aa and insensitive to Cry1Ac. Toxicity of Cry toxin can be correlated with the presence of a specific receptor in midgut epithelial cell membrane in insect. In surface plasmon resonance (SPR) and ligand blot analysis, however, many kinds of brush border membrane vesicle (BBMV) proteins were shown to bind to Cry1Ac with almost equal intensity in both resistance and susceptible insects. This suggests that majority of the bindings bet...

  3. Uniform orientation of biotinylated nanobody as an affinity binder for detection of Bacillus thuringiensis (Bt) Cry1Ac toxin.

    Science.gov (United States)

    Li, Min; Zhu, Min; Zhang, Cunzheng; Liu, Xianjin; Wan, Yakun

    2014-01-01

    Nanobodies are the smallest natural fragments with useful properties such as high affinity, distinct paratope and high stability, which make them an ideal tool for detecting target antigens. In this study, we generated and characterized nanobodies against the Cry1Ac toxin and applied them in a biotin-streptavidin based double antibodies (nanobodies) sandwich-ELISA (DAS-ELISA) assay. After immunizing a camel with soluble Cry1Ac toxin, a phage displayed library was constructed to generate Nbs against the Cry1Ac toxin. Through successive rounds of affinity bio-panning, four nanobodies with greatest diversity in CDR3 sequences were obtained. After affinity determination and conjugating to HRP, two nanobodies with high affinity which can recognize different epitopes of the same antigen (Cry1Ac) were selected as capture antibody (Nb61) and detection antibody (Nb44). The capture antibody (Nb61) was biotinylated in vivo for directional immobilization on wells coated with streptavidin matrix. Both results of specificity analysis and thermal stability determination add support for reliability of the following DAS-ELISA with a minimum detection limit of 0.005 μg·mL-1 and a working range 0.010-1.0 μg·mL-1. The linear curve displayed an acceptable correlation coefficient of 0.9976. These results indicated promising applications of nanobodies for detection of Cry1Ac toxin with biotin-streptavidin based DAS-ELISA system. PMID:25474492

  4. Uniform Orientation of Biotinylated Nanobody as an Affinity Binder for Detection of Bacillus thuringiensis (Bt Cry1Ac Toxin

    Directory of Open Access Journals (Sweden)

    Min Li

    2014-12-01

    Full Text Available Nanobodies are the smallest natural fragments with useful properties such as high affinity, distinct paratope and high stability, which make them an ideal tool for detecting target antigens. In this study, we generated and characterized nanobodies against the Cry1Ac toxin and applied them in a biotin-streptavidin based double antibodies (nanobodies sandwich-ELISA (DAS-ELISA assay. After immunizing a camel with soluble Cry1Ac toxin, a phage displayed library was constructed to generate Nbs against the Cry1Ac toxin. Through successive rounds of affinity bio-panning, four nanobodies with greatest diversity in CDR3 sequences were obtained. After affinity determination and conjugating to HRP, two nanobodies with high affinity which can recognize different epitopes of the same antigen (Cry1Ac were selected as capture antibody (Nb61 and detection antibody (Nb44. The capture antibody (Nb61 was biotinylated in vivo for directional immobilization on wells coated with streptavidin matrix. Both results of specificity analysis and thermal stability determination add support for reliability of the following DAS-ELISA with a minimum detection limit of 0.005 μg·mL−1 and a working range 0.010–1.0 μg·mL−1. The linear curve displayed an acceptable correlation coefficient of 0.9976. These results indicated promising applications of nanobodies for detection of Cry1Ac toxin with biotin-streptavidin based DAS-ELISA system.

  5. Uniform Orientation of Biotinylated Nanobody as an Affinity Binder for Detection of Bacillus thuringiensis (Bt) Cry1Ac Toxin

    Science.gov (United States)

    Li, Min; Zhu, Min; Zhang, Cunzheng; Liu, Xianjin; Wan, Yakun

    2014-01-01

    Nanobodies are the smallest natural fragments with useful properties such as high affinity, distinct paratope and high stability, which make them an ideal tool for detecting target antigens. In this study, we generated and characterized nanobodies against the Cry1Ac toxin and applied them in a biotin-streptavidin based double antibodies (nanobodies) sandwich-ELISA (DAS-ELISA) assay. After immunizing a camel with soluble Cry1Ac toxin, a phage displayed library was constructed to generate Nbs against the Cry1Ac toxin. Through successive rounds of affinity bio-panning, four nanobodies with greatest diversity in CDR3 sequences were obtained. After affinity determination and conjugating to HRP, two nanobodies with high affinity which can recognize different epitopes of the same antigen (Cry1Ac) were selected as capture antibody (Nb61) and detection antibody (Nb44). The capture antibody (Nb61) was biotinylated in vivo for directional immobilization on wells coated with streptavidin matrix. Both results of specificity analysis and thermal stability determination add support for reliability of the following DAS-ELISA with a minimum detection limit of 0.005 μg·mL−1 and a working range 0.010–1.0 μg·mL−1. The linear curve displayed an acceptable correlation coefficient of 0.9976. These results indicated promising applications of nanobodies for detection of Cry1Ac toxin with biotin-streptavidin based DAS-ELISA system. PMID:25474492

  6. Characterization of the mucosal and systemic immune response induced by Cry1Ac protein from Bacillus thuringiensis HD 73 in mice

    Directory of Open Access Journals (Sweden)

    R.I. Vázquez-Padrón

    2000-02-01

    Full Text Available The present paper describes important features of the immune response induced by the Cry1Ac protein from Bacillus thuringiensis in mice. The kinetics of induction of serum and mucosal antibodies showed an immediate production of anti-Cry1Ac IgM and IgG antibodies in serum after the first immunization with the protoxin by either the intraperitoneal or intragastric route. The antibody fraction in serum and intestinal fluids consisted mainly of IgG1. In addition, plasma cells producing anti-Cry1Ac IgG antibodies in Peyer's patches were observed using the solid-phase enzyme-linked immunospot (ELISPOT. Cry1Ac toxin administration induced a strong immune response in serum but in the small intestinal fluids only anti-Cry1Ac IgA antibodies were detected. The data obtained in the present study confirm that the Cry1Ac protoxin is a potent immunogen able to induce a specific immune response in the mucosal tissue, which has not been observed in response to most other proteins.

  7. Growth, productivity, and competitiveness of introgressed weedy Brassica rapa hybrids selected for the presence of Bt cry1Ac and gfp transgenes.

    Science.gov (United States)

    Halfhill, Matthew D; Sutherland, Jamie P; Moon, Hong Seok; Poppy, Guy M; Warwick, Suzanne I; Weissinger, Arthur K; Rufty, Thomas W; Raymer, Paul L; Stewart, C Neal

    2005-09-01

    Concerns exist that transgenic crop x weed hybrid populations will be more vigorous and competitive with crops compared with the parental weed species. Hydroponic, glasshouse, and field experiments were performed to evaluate the effects of introgression of Bacillus thuringiensis (Bt) cry1Ac and green fluorescent protein (GFP) transgenes on hybrid productivity and competitiveness in four experimental Brassica rapa x transgenic Brassica napus hybrid generations (F1, BC1F1, BC2F1 and BC2F2). The average vegetative growth and nitrogen (N) use efficiency of transgenic hybrid generations grown under high N hydroponic conditions were lower than that of the weed parent (Brassica rapa, AA, 2n = 20), but similar to the transgenic crop parent, oilseed rape (Brassica napus, AACC, 2n = 38). No generational differences were detected under low N conditions. In two noncompetitive glasshouse experiments, both transgenic and nontransgenic BC2F2 hybrids had on average less vegetative growth and seed production than B. rapa. In two high intraspecific competition field experiments with varied herbivore pressure, BC2F2 hybrids produced less vegetative dry weight than B. rapa. The competitive ability of transgenic and nontransgenic BC2F2 hybrids against a neighbouring crop species were quantified in competition experiments that assayed wheat (Triticum aestivum) yield reductions under agronomic field conditions. The hybrids were the least competitive with wheat compared with parental Brassica competitors, although differences between transgenic and nontransgenic hybrids varied with location. Hybridization, with or without transgene introgression, resulted in less productive and competitive populations. PMID:16101783

  8. Mutation of an aminopeptidase N gene is associated with Helicoverpa armigera resistance to Bacillus thuringiensis Cry1Ac toxin.

    Science.gov (United States)

    Zhang, Shaoping; Cheng, Hongmei; Gao, Yulin; Wang, Guirong; Liang, Gemei; Wu, Kongming

    2009-07-01

    A Cry1Ac-resistant strain (Bt-R) of Helicoverpa armigera, with 2971-fold resistance, was derived by selection with Cry1Ac toxin for 75 generations. We used cDNA-amplified fragment length polymorphism analysis to identify those genes differentially expressed in the Cry1Ac-resistant and -susceptible strains, which revealed 212 differentially expressed transcripts among 2000 screened cDNAs. Among these transcript-derived fragments (TDFs), 37 showed some homology to known sequences, including Aminopeptidase N (APN), which is expressed in the midgut epithelium and has been implicated as a Cry1A subfamily receptor in several moths, including H. armigera. We confirmed the TDF by RT-PCR and identified a deletion mutation of apn1 in the Bt-R strain. We expressed the TDF in bacteria. The partial HaAPN1-96S wild-type protein, bound to Cry1Ac on ligand blots, whereas HaAPN1-BtR did not. This suggested that HaAPN1 is a receptor for Bt Cry1Ac and that its deletion mutation is associated with Cry1Ac resistance in H. armigera. The absence of one binding site is responsible for its resistance to Cry1Ac. We developed an allele-specific PCR to monitor whether the apn1 gene in an H. armigera field population produced a similar mutation. No deleted mutants were found in 2250 individuals collected from the field in 2006-2007. PMID:19376227

  9. Identification of Cry1Ac and Cry2Ab proteins in transgenic cotton seeds available in Gujarat (India by ELISA method

    Directory of Open Access Journals (Sweden)

    Alka Dohare

    2014-02-01

    Full Text Available Along with the increase market of the transgenic crops, the demand for testing GMOs and for certifying non-GMO foodstuffs has increased dramatically. Within the arena of expanding techniques for identification and quantification of transgenic crops, two major approaches for detecting GMOs are still applicable on large scale, namely ELISA based protein detection and PCR based gene identification. In present study, ELISA techniques was adopted to identify the specific Cry1Ac and Cry2Ab proteins in some transgenic cotton plants seed samples viz., Gujarat cotton hybrid – 6 (BG II, Gujarat cotton hybrid – 8 (BG II and Gujarat cotton hybrid – 10 (BG II from the Gujarat state of India. The study reveals the presence of both Cry1Ac and Cry2Ab proteins in the transgenic seed samples and also demonstrated that the technique of ELISA for identification of Cry1Ac and Cry2Ab proteins is quite handy and easily adoptable.

  10. The interaction of two-spotted spider mites, Tetranychus urticae Koch, with Cry protein production and predation by Amblyseius andersoni (Chant) in Cry1Ac/Cry2Ab cotton and Cry1F maize.

    Science.gov (United States)

    Guo, Yan-Yan; Tian, Jun-Ce; Shi, Wang-Peng; Dong, Xue-Hui; Romeis, Jörg; Naranjo, Steven E; Hellmich, Richard L; Shelton, Anthony M

    2016-02-01

    Crops producing insecticidal crystal (Cry) proteins from the bacterium, Bacillus thuringiensis (Bt), are an important tool for managing lepidopteran pests on cotton and maize. However, the effects of these Bt crops on non-target organisms, especially natural enemies that provide biological control services, are required to be addressed in an environmental risk assessment. Amblyseius andersoni (Acari: Phytoseiidae) is a cosmopolitan predator of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), a significant pest of cotton and maize. Tri-trophic studies were conducted to assess the potential effects of Cry1Ac/Cry2Ab cotton and Cry1F maize on life history parameters (survival rate, development time, fecundity and egg hatching rate) of A. andersoni. We confirmed that these Bt crops have no effects on the biology of T. urticae and, in turn, that there were no differences in any of the life history parameters of A. andersoni when it fed on T. urticae feeding on Cry1Ac/Cry2Ab or non-Bt cotton and Cry1F or non-Bt maize. Use of a susceptible insect assay demonstrated that T. urticae contained biologically active Cry proteins. Cry proteins concentrations declined greatly as they moved from plants to herbivores to predators and protein concentration did not appear to be related to mite density. Free-choice experiments revealed that A. andersoni had no preference for Cry1Ac/Cry2Ab cotton or Cry1F maize-reared T. urticae compared with those reared on non-Bt cotton or maize. Collectively these results provide strong evidence that these crops can complement other integrated pest management tactics including biological control.

  11. Capturing the interaction types of two Bt toxins Cry1Ac and Cry2Ab on suppressing the cotton bollworm by using multi-exponential equations.

    Science.gov (United States)

    Shi, Pei-Jian; Wei, Ji-Zhen; Sandhu, Hardev S; Liang, Ge-Mei

    2016-08-01

    Transgenic crops are increasingly promoted for their practical effects on suppressing certain insect pests, but all transgenic crops are not equally successful. The insect pests can easily develop resistance against single Bacillus thuringiensis (Bt) toxin transgenic crops. Therefore, transgenic crops including two or more mixed Bt-toxins can solve this problem by delaying the resistance development and killing the majority of targeted pests before the evolution of resistance. It is important to test the controlling effects of transgenic crops including multiple mixed toxins on a particular insect pest. Previous research has checked the cross-resistance and interactions between Bt toxins Cry1Ac and Cry2Ab against one susceptible and four resistant strains of cotton bollworm. The results showed that independence was the main interaction type between two toxins for the susceptible strain, whereas synergism was the main interaction type for any one resistant strain. However, the optimal combinations of two toxins were not obtained. In the present study, we developed two multi-exponential equations (namely bi- and tri-exponential equations) to describe the combination effects of two Bt toxins. Importantly, the equations can provide predictions of combination effects of different continuous concentrations of two toxins. We compared these two multi-exponential equations with the generalized linear model (GLM) in describing the combination effects, and found that the bi- and tri-exponential equations are better than GLM. Moreover, the bi-exponential equation can also provide the optimal dose combinations for two toxins. PMID:26314801

  12. Toxicity and binding analyses of Bacillus thuringiensis toxin Vip3A in Cry1Ac-resistant and-susceptible strains of Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qian; CHEN Li-zhen; LU Qiong; ZHANG Yan; LIANG Ge-mei

    2015-01-01

    The Bacil us thuringiensis vegetative insecticidal protein, Vip3A, represents a new family of Bt toxin and is currently ap-plied to commercial transgenic cotton. To determine whether the Cry1Ac-resistant Helicoverpa armigera is cross-resistant to Vip3Aa protein, insecticidal activities, proteolytic activations and binding properties of Vip3Aa toxin were investigated using Cry1Ac-susceptible (96S) and Cry1Ac-resistant H. armigera strain (Cry1Ac-R). The toxicity of Vip3Aa in Cry1Ac-R slightly reduced compared with 96S, the resistance ratio was only 1.7-fold. The digestion rate of ful-length Vip3Aa by gut juice extracts from 96S was little faster than that from Cry1Ac-R. Surface plasmon resonance (SPR) showed there was no signiifcant difference between the binding afifnity of Vip3Aa and BBMVs between 96S and Cry1Ac-R strains, and there was no signiifcant competitive binding between Vip3Aa and Cry1Ac in susceptible or resistant strains. So there had little cross-resistance between Vip3Aa and Cry1Ac,Vip3A+Cry proteins maybe the suitable pyramid strategy to control H. armigera in China in the future.

  13. 40 CFR 174.510 - Bacillus thuringiensis Cry1Ac protein in all plants; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bacillus thuringiensis Cry1Ac protein in all plants; exemption from the requirement of a tolerance. 174.510 Section 174.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PROCEDURES AND REQUIREMENTS FOR PLANT-INCORPORATED PROTECTANTS...

  14. Cry1Ac 基因抗虫棉与其亲本棉花根际真菌多样性的比较%Comparison Between Transgenic Insect-Resistant Cotton Expressing Cry1Ac Protein and Its Parental Variety in Rhizospheric Fungal Diversity

    Institute of Scientific and Technical Information of China (English)

    潘建刚; 焦海华; 白志辉; 齐鸿雁; 马安周; 庄国强; 张洪勋

    2014-01-01

    在温室条件下,利用 PCR-DGGE 技术和 Q-PCR 技术分析了两种转 Cry1Ac 基因抗虫棉及其亲本棉花在不同取样时期的根际真菌多样性和生物量的动态变化情况,以评价其生态安全。结果表明,转 Bt 基因棉与对照棉根际真菌优势条带组成在不同的取样时期极为相似,三者间差异条带多为不清晰的条带。转 Bt 棉 SGK321根际真菌的生物量在苗期明显低于亲本对照,转 Bt 棉 XP188根际真菌的生物量在花铃期较对照有轻微降低,其它时期两种转 Bt 棉根际真菌生物量没有显著降低,甚至还有增加的趋势。不过根际真菌群落结构的改变和生物量的差异不仅存在于转基因棉和其亲本对照棉之间,它同样存在于对照棉 SHIYUAN321和 JM20之间以及转基因棉 SGK321和 XP188之间。可见 Bt 并不是造成转基因棉和非转基因棉根际真菌群落结构差异、多样性改变和生物量减少的唯一诱因,品种的不同也对它们也有影响。%The dynamics of rhizospheric fungal diversity and biomass at different sampling stages associated with two transgenic insect-resistant cottons expressing Cry1Ac protein and their control varieties were studied under greenhouse conditions, followed by PCR-denaturing gradient gel electrophoresis ( PCR-DGGE) and quantitative real-time polymerase chain reaction ( Q-PCR), in order to evaluate the ecological security of planting transgenic cotton expressing Cry1Ac protein. The results indicated that the fungal superior bands in rhizosphere of transgenic Bt cotton were similar with that of control cotton at four sampling stages, the more obvious difference in the blurred bands among transgenic Bt cotton, JM20 and SHIYUAN321 was detected. The rhizospheric fungal biomass of transgenic Bt cotton SGK321 was significantly lower than that of its parental control cotton at seedling stage, while the slight decrease in fungal biomass of transgenic Bt cotton XP188

  15. High Expression of Cry1Ac Protein in Cotton (Gossypium hirsutum) by Combining Independent Transgenic Events that Target the Protein to Cytoplasm and Plastids

    Science.gov (United States)

    Singh, Amarjeet Kumar; Paritosh, Kumar; Kant, Uma; Burma, Pradeep Kumar; Pental, Deepak

    2016-01-01

    Transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1Ac gene (1,848 bp), which was originally characterized from Bacillus thuringiensis subspecies kurstaki strain HD73 that encodes a toxin highly effective against many lepidopteran pests. In Construct I, the cry1Ac gene was cloned under FMVde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. In Construct II, the encoded protein was directed to the plastids using a transit peptide taken from the cotton rbcSIb gene. Genetic transformation experiments with Construct I resulted in a single copy insertion event in which the Cry1Ac protein expression level was 2–2.5 times greater than in the Bacillus thuringiensis cotton event Mon 531, which is currently used in varieties and hybrids grown extensively in India and elsewhere. Another high expression event was selected from transgenics developed with Construct II. The Cry protein expression resulting from this event was observed only in the green plant parts. No transgenic protein expression was observed in the non-green parts, including roots, seeds and non-green floral tissues. Thus, leucoplasts may lack the mechanism to allow entry of a protein tagged with the transit peptide from a protein that is only synthesized in tissues containing mature plastids. Combining the two events through sexual crossing led to near additive levels of the toxin at 4–5 times the level currently used in the field. The two high expression events and their combination will allow for effective resistance management against lepidopteran insect pests, particularly Helicoverpa armigera, using a high dosage strategy. PMID:27391960

  16. High Expression of Cry1Ac Protein in Cotton (Gossypium hirsutum by Combining Independent Transgenic Events that Target the Protein to Cytoplasm and Plastids.

    Directory of Open Access Journals (Sweden)

    Amarjeet Kumar Singh

    Full Text Available Transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1Ac gene (1,848 bp, which was originally characterized from Bacillus thuringiensis subspecies kurstaki strain HD73 that encodes a toxin highly effective against many lepidopteran pests. In Construct I, the cry1Ac gene was cloned under FMVde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. In Construct II, the encoded protein was directed to the plastids using a transit peptide taken from the cotton rbcSIb gene. Genetic transformation experiments with Construct I resulted in a single copy insertion event in which the Cry1Ac protein expression level was 2-2.5 times greater than in the Bacillus thuringiensis cotton event Mon 531, which is currently used in varieties and hybrids grown extensively in India and elsewhere. Another high expression event was selected from transgenics developed with Construct II. The Cry protein expression resulting from this event was observed only in the green plant parts. No transgenic protein expression was observed in the non-green parts, including roots, seeds and non-green floral tissues. Thus, leucoplasts may lack the mechanism to allow entry of a protein tagged with the transit peptide from a protein that is only synthesized in tissues containing mature plastids. Combining the two events through sexual crossing led to near additive levels of the toxin at 4-5 times the level currently used in the field. The two high expression events and their combination will allow for effective resistance management against lepidopteran insect pests, particularly Helicoverpa armigera, using a high dosage strategy.

  17. High Expression of Cry1Ac Protein in Cotton (Gossypium hirsutum) by Combining Independent Transgenic Events that Target the Protein to Cytoplasm and Plastids.

    Science.gov (United States)

    Singh, Amarjeet Kumar; Paritosh, Kumar; Kant, Uma; Burma, Pradeep Kumar; Pental, Deepak

    2016-01-01

    Transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1Ac gene (1,848 bp), which was originally characterized from Bacillus thuringiensis subspecies kurstaki strain HD73 that encodes a toxin highly effective against many lepidopteran pests. In Construct I, the cry1Ac gene was cloned under FMVde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. In Construct II, the encoded protein was directed to the plastids using a transit peptide taken from the cotton rbcSIb gene. Genetic transformation experiments with Construct I resulted in a single copy insertion event in which the Cry1Ac protein expression level was 2-2.5 times greater than in the Bacillus thuringiensis cotton event Mon 531, which is currently used in varieties and hybrids grown extensively in India and elsewhere. Another high expression event was selected from transgenics developed with Construct II. The Cry protein expression resulting from this event was observed only in the green plant parts. No transgenic protein expression was observed in the non-green parts, including roots, seeds and non-green floral tissues. Thus, leucoplasts may lack the mechanism to allow entry of a protein tagged with the transit peptide from a protein that is only synthesized in tissues containing mature plastids. Combining the two events through sexual crossing led to near additive levels of the toxin at 4-5 times the level currently used in the field. The two high expression events and their combination will allow for effective resistance management against lepidopteran insect pests, particularly Helicoverpa armigera, using a high dosage strategy. PMID:27391960

  18. Identification of ABCC2 as a binding protein of Cry1Ac on brush border membrane vesicles from Helicoverpa armigera by an improved pull-down assay.

    Science.gov (United States)

    Zhou, Zishan; Wang, Zeyu; Liu, Yuxiao; Liang, Gemei; Shu, Changlong; Song, Fuping; Zhou, Xueping; Bravo, Alejandra; Soberón, Mario; Zhang, Jie

    2016-08-01

    Cry1Ac toxin-binding proteins from Helicoverpa armigera brush border membrane vesicles were identified by an improved pull-down method that involves coupling Cry1Ac to CNBr agarose combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). According to the LC-MS/MS results, Cry1Ac toxin could bind to six classes of aminopeptidase-N, alkaline phosphatase, cadherin-like protein, ATP-binding cassette transporter subfamily C protein (ABCC2), actin, ATPase, polycalin, and some other proteins not previously characterized as Cry toxin-binding molecules such as dipeptidyl peptidase or carboxyl/choline esterase and some serine proteases. This is the first report that suggests the direct binding of Cry1Ac toxin to ABCC2 in H. armigera. PMID:27037552

  19. 烟夜蛾幼虫中肠Bt Cry1Ac毒素受体蛋白cDNA片段的克隆和序列测定%Molecular Cloning and Sequencing of cDNA Fragment Encoding Bt Cry1Ac Toxin Binding Protein from the Midgut of Helicoverpa assulta Guenée Larva

    Institute of Scientific and Technical Information of China (English)

    安世恒; 郭线茹; 罗梅浩; 蒋金炜; 马继盛

    2005-01-01

    利用RT-PCR技术扩增烟夜蛾(Helicoverpa assulta Guenée)幼虫中肠Bt毒素Cry1Ac受体蛋白APN(N-氨基肽酶,aminopeptidase N,APN)基因片段,克隆和测序结果表明,测序得到的812 bp的片段编码270个氨基酸残基,且该片段在阅读框内.通过同源性分析发现,其核苷酸序列与棉铃虫(H. armigera)、澳洲棉铃虫(H. punctigera)、烟芽夜蛾(H. virescens)、舞毒蛾(Lymantria dispar)、小菜蛾(Plutella xylostella)、印度谷螟(Plodia interpunctella)RC688品系和HD198品系、烟草天蛾(Manduca sexta)和家蚕(Bombyx mori)的Cry1Ac受体蛋白基因的同源性分别为97.0%,90.0%,78.0%,63.5%,55.0%,60.3%,61.2%,55.0%和59.0%.推导的烟夜蛾Cry1Ac受体蛋白基因的氨基酸序列与棉铃虫、烟芽夜蛾、斑实夜蛾、舞毒蛾的氨基酸序列同源性分别为95.6%,81.0%,82.7%和55.7%.该片段编码的氨基酸属于氨肽酶家族,与烟夜蛾对Bt Cry1Ac毒素的抗性有关.

  20. Shared midgut binding sites for Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac and Cry1Fa proteins from Bacillus thuringiensis in two important corn pests, Ostrinia nubilalis and Spodoptera frugiperda.

    Directory of Open Access Journals (Sweden)

    Carmen Sara Hernández-Rodríguez

    Full Text Available First generation of insect-protected transgenic corn (Bt-corn was based on the expression of Cry1Ab or Cry1Fa proteins. Currently, the trend is the combination of two or more genes expressing proteins that bind to different targets. In addition to broadening the spectrum of action, this strategy helps to delay the evolution of resistance in exposed insect populations. One of such examples is the combination of Cry1A.105 with Cry1Fa and Cry2Ab to control O. nubilalis and S. frugiperda. Cry1A.105 is a chimeric protein with domains I and II and the C-terminal half of the protein from Cry1Ac, and domain III almost identical to Cry1Fa. The aim of the present study was to determine whether the chimeric Cry1A.105 has shared binding sites either with Cry1A proteins, with Cry1Fa, or with both, in O. nubilalis and in S. frugiperda. Brush-border membrane vesicles (BBMV from last instar larval midguts were used in competition binding assays with (125I-labeled Cry1A.105, Cry1Ab, and Cry1Fa, and unlabeled Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac, Cry1Fa, Cry2Ab and Cry2Ae. The results showed that Cry1A.105, Cry1Ab, Cry1Ac and Cry1Fa competed with high affinity for the same binding sites in both insect species. However, Cry2Ab and Cry2Ae did not compete for the binding sites of Cry1 proteins. Therefore, according to our results, the development of cross-resistance among Cry1Ab/Ac, Cry1A.105, and Cry1Fa proteins is possible in these two insect species if the alteration of shared binding sites occurs. Conversely, cross-resistance between these proteins and Cry2A proteins is very unlikely in such case.

  1. Comparison and optimization of the method for Cry1Ac protoxin preparation in HD73 strain

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zi-shan; YANG Su-juan; SHU Chang-long; SONG Fu-ping; ZHOU Xue-ping; ZHANG Jie

    2015-01-01

    Bacil us thuringiensis is one of the most widely used bioinsecticides, and cry gene is the major insecticidal gene. Because Cry1Ac protein shows strong toxicity against many lepidopteran species, it has been applied widely in spraying products and transgenic Bt-crops. The preparation of Cry protoxin is the ifrst step in the very important processes of understanding the insecticidal mechanism, resistance screening, and biosafety assessments. The media for crystal production and the method for Cry protoxin preparation were varied, however, it was not clear which was better for preparing a larger amount of Cry protoxin. In this paper, three media for crystal production and the method for Cry1Ac protoxin preparation from HD73 strain were compared to ifnd an efifcacious way to prepare a large number of Cry1Ac protoxin. The results showed that the 1/2 LB (Luria-Bertani) medium was the ideal medium for crystal production, because the total yield of Cry1Ac protoxin in 300 mL 1/2 LB medium was (112.38±5.64) mg, the highest one among three media;the repeated crystal solubilization method was better for the preparation of the Cry protoxin comparing with the continuous crystal solubilization method. It wil be a reference for other Cry protoxin preparation, especial y for larger number.

  2. Prays oleae midgut putative receptor of Bacillus thuringiensis vegetative insecticidal protein Vip3LB differs from that of Cry1Ac toxin.

    Science.gov (United States)

    Abdelkefi-Mesrati, Lobna; Rouis, Souad; Sellami, Sameh; Jaoua, Samir

    2009-09-01

    Vegetative insecticidal protein (Vip) is a class of insecticidal proteins produced by many Bacillus thuringiensis strains during their vegetative growth stage. The vip3LB gene of B. thuringiensis strain BUPM95, which encodes a protein active against the Lepidoptera olive tree pathogenic insect Prays oleae, was cloned into pET-14b vector and overexpressed in Escherichia coli. The expressed Vip3LB protein, found in the E. coli cytoplasmic fraction, was purified and used to produce anti-Vip3LB antibodies. Using the midgut extract of P. oleae, the purified Vip3LB bound to a 65-kDa protein, whereas Cry1Ac toxin bound to a 210-kDa midgut putative receptor. This result justifies the importance of the biological pest control agent Vip3LB that could be used as another alternative particularly in case of resistance to Cry toxins. PMID:19434523

  3. pH-controlled Bacillus thuringiensis Cry1Ac protoxin loading and release from polyelectrolyte microcapsules.

    Directory of Open Access Journals (Sweden)

    Wenhui Yang

    Full Text Available Crystal proteins synthesized by Bacillus thuringiensis (Bt have been used as biopesticides because of their toxicity to the insect larval hosts. To protect the proteins from environmental stress to extend their activity, we have developed a new microcapsule formulation. Poly (acrylic acid (PAH and poly (styrene sulfonate (PSS were fabricated through layer-by-layer self-assembly based on a CaCO(3 core. Cry1Ac protoxins were loaded into microcapsules through layer-by-layer self-assembly at low pH, and the encapsulated product was stored in water at 4°C. Scanning electron microscopy (SEM was used to observe the morphology of the capsules. To confirm the successful encapsulation, the loading results were observed with a confocal laser scattering microscope (CLSM, using fluorescein-labeled Cry1Ac protoxin (FITC-Cry1Ac. The protoxins were released from the capsule under the alkaline condition corresponding to the midgut of certain insects, a condition which seldom exists elsewhere in the environment. The following bioassay experiment demonstrated that the microcapsules with Cry1Ac protoxins displayed approximately equivalent insecticidal activity to the Asian corn borer compared with free Cry1Ac protoxins, and empty capsules proved to have no effect on insects. Further result also indicated that the formulation could keep stable under the condition of heat and desiccation. These results suggest that this formulation provides a promising methodology that protects protoxins from the environment and releases them specifically in the target insects' midgut, which has shown potential as biopesticide in the field.

  4. MAPK signaling pathway alters expression of midgut ALP and ABCC genes and causes resistance to Bacillus thuringiensis Cry1Ac toxin in diamondback moth.

    Directory of Open Access Journals (Sweden)

    Zhaojiang Guo

    2015-04-01

    Full Text Available Insecticidal crystal toxins derived from the soil bacterium Bacillus thuringiensis (Bt are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. However, large-scale use of Bt has led to field-evolved resistance in several lepidopteran pests. Resistance to Bt Cry1Ac toxin in the diamondback moth, Plutella xylostella (L., was previously mapped to a multigenic resistance locus (BtR-1. Here, we assembled the 3.15 Mb BtR-1 locus and found high-level resistance to Cry1Ac and Bt biopesticide in four independent P. xylostella strains were all associated with differential expression of a midgut membrane-bound alkaline phosphatase (ALP outside this locus and a suite of ATP-binding cassette transporter subfamily C (ABCC genes inside this locus. The interplay between these resistance genes is controlled by a previously uncharacterized trans-regulatory mechanism via the mitogen-activated protein kinase (MAPK signaling pathway. Molecular, biochemical, and functional analyses have established ALP as a functional Cry1Ac receptor. Phenotypic association experiments revealed that the recessive Cry1Ac resistance was tightly linked to down-regulation of ALP, ABCC2 and ABCC3, whereas it was not linked to up-regulation of ABCC1. Silencing of ABCC2 and ABCC3 in susceptible larvae reduced their susceptibility to Cry1Ac but did not affect the expression of ALP, whereas suppression of MAP4K4, a constitutively transcriptionally-activated MAPK upstream gene within the BtR-1 locus, led to a transient recovery of gene expression thereby restoring the susceptibility in resistant larvae. These results highlight a crucial role for ALP and ABCC genes in field-evolved resistance to Cry1Ac and reveal a novel trans-regulatory signaling mechanism responsible for modulating the expression of these pivotal genes in P. xylostella.

  5. MAPK signaling pathway alters expression of midgut ALP and ABCC genes and causes resistance to Bacillus thuringiensis Cry1Ac toxin in diamondback moth.

    Science.gov (United States)

    Guo, Zhaojiang; Kang, Shi; Chen, Defeng; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhu, Xun; Baxter, Simon W; Zhou, Xuguo; Jurat-Fuentes, Juan Luis; Zhang, Youjun

    2015-04-01

    Insecticidal crystal toxins derived from the soil bacterium Bacillus thuringiensis (Bt) are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. However, large-scale use of Bt has led to field-evolved resistance in several lepidopteran pests. Resistance to Bt Cry1Ac toxin in the diamondback moth, Plutella xylostella (L.), was previously mapped to a multigenic resistance locus (BtR-1). Here, we assembled the 3.15 Mb BtR-1 locus and found high-level resistance to Cry1Ac and Bt biopesticide in four independent P. xylostella strains were all associated with differential expression of a midgut membrane-bound alkaline phosphatase (ALP) outside this locus and a suite of ATP-binding cassette transporter subfamily C (ABCC) genes inside this locus. The interplay between these resistance genes is controlled by a previously uncharacterized trans-regulatory mechanism via the mitogen-activated protein kinase (MAPK) signaling pathway. Molecular, biochemical, and functional analyses have established ALP as a functional Cry1Ac receptor. Phenotypic association experiments revealed that the recessive Cry1Ac resistance was tightly linked to down-regulation of ALP, ABCC2 and ABCC3, whereas it was not linked to up-regulation of ABCC1. Silencing of ABCC2 and ABCC3 in susceptible larvae reduced their susceptibility to Cry1Ac but did not affect the expression of ALP, whereas suppression of MAP4K4, a constitutively transcriptionally-activated MAPK upstream gene within the BtR-1 locus, led to a transient recovery of gene expression thereby restoring the susceptibility in resistant larvae. These results highlight a crucial role for ALP and ABCC genes in field-evolved resistance to Cry1Ac and reveal a novel trans-regulatory signaling mechanism responsible for modulating the expression of these pivotal genes in P. xylostella. PMID:25875245

  6. Transgenic tobacco plants expressing synthetic Cry1Ac and Cry1le genes are more toxic to cotton bollworm than those containing one gene

    Institute of Scientific and Technical Information of China (English)

    LIAN Yun; JIA ZhiWei; HE KangLai; LIU YunJun; SONG FuPing; WANG BaoMin; WANG GuoYing

    2008-01-01

    Transgenic tobacco plants carrying Cry1Ac, Crylle or both genes were obtained. In the leaves of transgenic plants carrying both genes, the contents of CrylAc and Cry1le proteins were 0.173% and 0.131% of the total proteins, respectively, Cry1Ac protein content was 0.182 % and Cry1le protein con-tent was 0.124% of the total proteins in the leaves of transgenic plants containing only one Bt gone. Fresh leaves of transgenic tobacco and wild-type plants were used for the insect bioassay against wild-type and Cry1Ac-resistant cotton bollworm (Helicoverpa armigera). The bioassay results showed that transgenic plants carrying both genes were significantly more toxic to wild-type and Cry1Ac-resistant cotton bollworm than those carrying Cry1Ac or Cry1le alone. This study indicates that the higher toxicity of transgenic tobacco plants carrying both genes is caused by the cooperative function of both Bt proteins, thus providing a potential way to delay the development of insect resis-tance to transgenic crops.

  7. Cadherin is involved in the action of Bacillus thuringiensis toxins Cry1Ac and Cry2Aa in the beet armyworm, Spodoptera exigua.

    Science.gov (United States)

    Qiu, Lin; Hou, Leilei; Zhang, Boyao; Liu, Lang; Li, Bo; Deng, Pan; Ma, Weihua; Wang, Xiaoping; Fabrick, Jeffrey A; Chen, Lizhen; Lei, Chaoliang

    2015-05-01

    Bacillus thuringiensis (Bt) insecticidal crystal (Cry) proteins are effective against some insect pests in sprays and transgenic crops, although the evolution of resistance could threaten the long-term efficacy of such Bt use. One strategy to delay resistance to Bt crops is to "pyramid" two or more Bt proteins that bind to distinct receptor proteins within the insect midgut. The most common Bt pyramid in cotton (Gossypium hirsutum L.) employs Cry1Ac with Cry2Ab to target several key lepidopteran pests, including the beet armyworm, Spodoptera exigua (Hübner), which is a serious migratory pest of many vegetable crops and is increasingly important in cotton in China. While cadherin and aminopeptidase-N are key receptors of Cry1 toxins in many lepidopterans including S. exigua, the receptor for Cry2A toxins remains poorly characterized. Here, we show that a heterologous expressed peptide corresponding to cadherin repeat 7 to the membrane proximal extracellular domain (CR7-MPED) in the S. exigua cadherin 1b (SeCad1b) binds Cry1Ac and Cry2Aa. Moreover, SeCad1b transcription was suppressed in S. exigua larvae by oral RNA interference and susceptibility to Cry1Ac and Cry2Aa was significantly reduced. These results indicate that SeCad1b plays important functional roles of both Cry1Ac and Cry2Aa, having major implications for resistance management for S. exigua in Bt crops. PMID:25754522

  8. Transmission of Cry1Ac from transgenic Bt cotton to the predatory ladybug Propylaea japonica via the whitefly Bemisia tabaci%转Bt基因棉花中Cry1Ac蛋白经烟粉虱途径向龟纹瓢虫的传递

    Institute of Scientific and Technical Information of China (English)

    周福才; 顾爱祥; 杨益众; 苏宏华; 胡其靖; 杨爱民

    2015-01-01

    【目的】烟粉虱Bemisia tabaci是转基因棉的非靶标害虫,对棉花生产造成严重影响。本文探讨转Bt基因棉花中Cry1Ac蛋白在棉花-烟粉虱-龟纹瓢食物链中的传递规律,以期为转基因棉的环境安全评价提供科学依据。【方法】在实验室条件下,以常规棉SM3号、33、SY321为对照,分析转Bt基因棉花GK12、XM33B、SGK321叶片、在这些棉花上取食的烟粉虱、以及捕食烟粉虱的瓢虫体内Cry1Ac蛋白含量。同时,将取食转 Bt 基因棉花上的烟粉虱的瓢虫转接到对应的受体亲本棉花上,分析瓢虫体内Cry1Ac蛋白含量变化规律。【结果】在转 Bt基因棉花上取食的烟粉虱成虫和若虫以及它们的蜜露中均能检测到Cry1Ac蛋白,以转Bt基因棉花上的烟粉虱若虫为食料的龟纹瓢虫体Propylaea japonica内也能检测到Cry1Ac蛋白。龟纹瓢虫取食转Bt基因棉花上的烟粉虱若虫1 d后体内即能检测到Cry1Ac蛋白,并且随着取食时间的延长,体内Cry1Ac蛋白的含量逐渐增加,但到第6~8天后Cry1Ac蛋白的含量相对稳定。取食3个不同品种棉花上烟粉虱若虫的龟纹瓢虫体内Cry1Ac蛋白的含量存在明显差异,这种差异与棉花叶片上表达的 Cry1Ac 蛋白量呈正相关。但取食后6 d,在3个品种棉花上取食的龟纹瓢虫体内的Cry1Ac蛋白含量之间没有明显的差异。以转Bt基因棉花上的烟粉虱若虫为食料的龟纹瓢虫转移到对应的常规棉亲本上以后,体内的 Cry1Ac 蛋白的含量迅速下降,但10 d 后仍能检测到微量的 Cry1Ac 蛋白。【结论】转Bt基因棉花中的Cry1Ac蛋白可以通过烟粉虱途径传递到龟纹瓢虫体内,龟纹瓢虫对食料中的 Cry1Ac 蛋白具有富集作用,并且 Cry1Ac 蛋白的富集存在饱和现象,富集饱和量与食料中的 Cry1Ac含量无关;龟纹瓢虫脱离含有Cry1Ac蛋白的食料环境后,体内的Cry1Ac

  9. Resistance of Trichoplusia ni to Bacillus thuringiensis toxin Cry1Ac is independent of alteration of the cadherin-like receptor for Cry toxins.

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    Full Text Available Alteration of binding sites for Bacillus thuringiensis (Bt toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptidase N (APN1 gene by a trans-regulatory mechanism and the resistance gene has been mapped to the locus of an ABC transporter (ABCC2 gene. However, whether cadherin is also involved with Cry1Ac-resistance in T. ni requires to be understood. Here we report that the Cry1Ac-resistance in T. ni is independent of alteration of the cadherin. The T. ni cadherin cDNA was cloned and the cadherin sequence showed characteristic features known to cadherins from Lepidoptera. Various T. ni cadherin gene alleles were identified and genetic linkage analysis of the cadherin alleles with Cry1Ac-resistance showed no association of the cadherin gene with the Cry1Ac-resistance in T. ni. Analysis of cadherin transcripts showed no quantitative difference between the susceptible and Cry1Ac-resistant T. ni larvae. Quantitative proteomic analysis of midgut BBMV proteins by iTRAQ-2D-LC-MS/MS determined that there was no quantitative difference in cadherin content between the susceptible and the resistant larvae and the cadherin only accounted for 0.0014% (mol% of the midgut BBMV proteins, which is 1/300 of APN1 in molar ratio. The cadherin from both the susceptible and resistant larvae showed as a 200-kDa Cry1Ac-binding protein by toxin overlay binding analysis, and nano-LC-MS/MS analysis of the 200-kDa cadherin determined that there is no quantitative difference between the susceptible and resistant larvae. Results from this study indicate that the Cry1Ac-resistance in T. ni is

  10. Resistance of Trichoplusia ni to Bacillus thuringiensis toxin Cry1Ac is independent of alteration of the cadherin-like receptor for Cry toxins.

    Science.gov (United States)

    Zhang, Xin; Tiewsiri, Kasorn; Kain, Wendy; Huang, Lihua; Wang, Ping

    2012-01-01

    Alteration of binding sites for Bacillus thuringiensis (Bt) toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptidase N (APN1) gene by a trans-regulatory mechanism and the resistance gene has been mapped to the locus of an ABC transporter (ABCC2) gene. However, whether cadherin is also involved with Cry1Ac-resistance in T. ni requires to be understood. Here we report that the Cry1Ac-resistance in T. ni is independent of alteration of the cadherin. The T. ni cadherin cDNA was cloned and the cadherin sequence showed characteristic features known to cadherins from Lepidoptera. Various T. ni cadherin gene alleles were identified and genetic linkage analysis of the cadherin alleles with Cry1Ac-resistance showed no association of the cadherin gene with the Cry1Ac-resistance in T. ni. Analysis of cadherin transcripts showed no quantitative difference between the susceptible and Cry1Ac-resistant T. ni larvae. Quantitative proteomic analysis of midgut BBMV proteins by iTRAQ-2D-LC-MS/MS determined that there was no quantitative difference in cadherin content between the susceptible and the resistant larvae and the cadherin only accounted for 0.0014% (mol%) of the midgut BBMV proteins, which is 1/300 of APN1 in molar ratio. The cadherin from both the susceptible and resistant larvae showed as a 200-kDa Cry1Ac-binding protein by toxin overlay binding analysis, and nano-LC-MS/MS analysis of the 200-kDa cadherin determined that there is no quantitative difference between the susceptible and resistant larvae. Results from this study indicate that the Cry1Ac-resistance in T. ni is independent of cadherin

  11. Climate change and genetically modified insecticidal plants. Plant-herbivore interactions and secondary chemistry of Bt Cry1Ac-toxin producing oilseed rape (Brassica napus L.) under elevated CO{sub 2} or O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, S.

    2008-07-01

    Transgenic insect-resistant plants producing Bacillus thuringiensis (Bt) crystalline endotoxins are the first commercial applications of genetically modified crops and their use has steadily expanded over the last ten years. Together with the expanding agricultural use of transgenic crops, climate change is predicted to be among the major factors affecting agriculture in the coming years. Plants, herbivores and insects of higher trophic levels are all predicted to be affected by the current atmospheric climate change. However, only very few studies to date have addressed the sustained use and herbivore interactions of Bt-producing plants under the influence of these abiotic factors. The main objective of this study was to comparatively assess the performance of a Bt Cry1Ac toxin-producing oilseed rape line and its non-transgenic parent line in terms of vegetative growth and allocation to secondary defence compounds (glucosinolates and volatile terpenoids), and the performance of Bt-target and nontarget insect herbivores as well as tritrophic interaction functioning on these lines. For this, several growth chamber experiments with vegetative stage non-Bt and Bt plants facing exposures to doubled atmospheric CO{sub 2} level alone or together with increased temperature and different regimes of elevated O{sub 3} were conducted. The main hypothesis of this work was that Bt-transgenic plants have reduced performance or allocation to secondary compounds due to the cost of producing Bt toxin under changed abiotic environments. The Bt-transgenic oilseed rape line exhibited slightly delayed vegetative growth and had increased nitrogen and reduced carbon content compared to the non-transgenic parent line, but the physiological responses (i.e. biomass gain and photosynthesis) of the plant lines to CO{sub 2} and O{sub 3} enhancements were equal. Two aphid species, non-susceptible to Bt Cry1Ac, showed equal performance and reproduction on both plant lines under elevated CO{sub 2

  12. Altered binding of the Cry1Ac toxin to larval membranes but not to the toxin-binding protein in Plodia interpunctella selected for resistance to different Bacillus thuringiensis isolates.

    Science.gov (United States)

    Mohammed, S I; Johnson, D E; Aronson, A I

    1996-11-01

    Immunoblotting and cytochemical procedures were used to determine whether toxin binding was altered in strains of the Indianmeal moth, Plodia interpunctella, selected for resistance to various strains of Bacillus thuringiensis. Each of these B. thuringiensis subspecies produces a mixture of protoxins, primarily Cry1 types, and the greatest insect resistance is to the Cry1A protoxins. In several cases, however, there was also resistance to toxins not present in the B. thuringiensis strains used for selection. The Cry1Ab and Cry1Ac toxins bound equally well over a range of toxin concentrations and times of incubation to a single protein of ca. 80-kDa in immunoblots of larval membrane extracts from all of the colonies. This binding protein is essential for toxicity since a mutant Cry1Ac toxin known to be defective in binding and thus less toxic bound poorly to the 80-kDa protein. This binding protein differed in size from the major aminopeptidase N antigens implicated in toxin binding in other insects. Binding of fluorescently labeled Cry1Ac or Cry1Ab toxin to larval sections was found at the tips of the brush border membrane prepared from the susceptible but not from any of the resistant P. interpunctella. Accessibility of a major Cry1A-binding protein appears to be altered in resistant larvae and could account for their broad resistance to several B. thuringiensis toxins.

  13. A Comprehensive Assessment of the Effects of Transgenic Cry1Ac/Cry1Ab Rice Huahui 1 on Adult Micraspis discolor (Fabricius (Coleoptera: Coccinellidae.

    Directory of Open Access Journals (Sweden)

    Xia Zhou

    Full Text Available Micraspis discolor (Fabricius (Coleoptera: Coccinellidae is a widely distributed coleoptera predator in southern Asia in rice ecosystem, and adult M. discolor feed on both rice pollen and soft-bodied arthropods. Bitrophic bioassay and tritrophic bioassay were conducted to evaluate the potential impact of Cry1Ac/Cry1Ab-expressing rice Huahui 1 and its non-transgenic counterpart Minghui 63 on fitness parameters of adult M. discolor. The results showed that the survival, and fecundity of this beetle' adults were not different when they fed on Bt rice or non-Bt rice pollen or Nilaparvata lugens (Stål reared on Bt rice or non-Bt rice. Toxicity assessment to ensure M. discolor adults were not sensitive to Cry1Ab or Cry1Ac protein independent from the pollen background, M. discolor adults were fed with an artificial diet containing Cry1Ac, Cry1Ab or both protein approximately 10 times higher concentration than in Huahui 1 rice pollen. No difference was detected for any of the life-table parameters tested between Cry protein-containing and pure diet. Artificial diet containing E-64 (N-(trans-Epoxysuccinyl-L-leucine 4-guanidinobutylamide was included as a positive control. In contrast, the pre-oviposition and fecundity of M. discolor were significantly adversely affected by feeding on E-64-containing diet. In both bioassays, the uptakes of Cry protein by adult M. discolor were tested by ELISA measurements. These results indicated that adults of M. discolor are not affected by Cry1Ab- or Cry1Ac-expressing rice pollen and are not sensitive to Cry protein at concentrations exceeding the levels in rice pollen in Huahui1. This suggests that M. discolor adults would not be harmed by Cry1Ac/Cry1Ab rice if Bt rice Huahui 1 were commercialized.

  14. EXPRESIÓN DE LA PROTEÍNA Cry1Ac EN TEJIDOS DE LÍNEASTRANSGÉNICAS DE PAPA (Solanum tuberosum spp. ANDÍGENAVAR. DIACOL CAPIRO. Cry1Ac Protein Expression in Tissues of Potato (Solanumtuberosum spp. Andígena Transgenic Lines Var. Diacol Capiro

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    PABLO ANDRÉS VANEGAS ARAUJO

    genetic plant breeding related to the introduction of Cry genes which codify insecticidal crystal proteins is an alternative for reducing the insect attack in commercial crops. In this work, the insertion, transcription and expression of Cry1Ac gen was characterized in different tissues and three development stages of two transgenic lines of Solanum tuberosum variety Diacol Capiro that were previously transformed by Agrobacterium tumefaciens method. The characterization was realized by PCR, RT-PCR and ELISA techniques. The gen insertion and transcription was confirmed using primers for Cry1Ac gen that amplified a specific band of 766 bp. The protein expression levels were higher than 45 µg/g and were not significantly different between the analyzed lines nor the three development stages. Furthermore, taking into account some relevant phenotypic features, no significant differences were found between transgenic lines and controls. The results suggest that monitoring and biosecurity assays are necessary with this vegetal material because their high level expression inside all the tissues analyzed that could affect non-targeted insects.

  15. Leaf morphology and ultrastructure responses to elevated O3 in transgenic Bt (cry1Ab/cry1Ac rice and conventional rice under fully open-air field conditions.

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    Chunyan Li

    Full Text Available BACKGROUND: Elevated tropospheric ozone severely affects not only yield but also the morphology, structure and physiological functions of plants. Because of concerns regarding the potential environmental risk of transgenic crops, it is important to monitor changes in transgenic insect-resistant rice under the projected high tropospheric ozone before its commercial release. METHODOLOGY/PRINCIPAL FINDINGS: Using a free-air concentration enrichment (FACE system, we investigated the changes in leaf morphology and leaf ultrastructure of two rice varieties grown in plastic pots, transgenic Bt Shanyou 63 (Bt-SY63, carrying a fusion gene of cry1Ab and cry1Ac and its non-transgenic counterpart (SY63, in elevated O3 (E-O3 versus ambient O3 (A-O3 after 64-DAS (Days after seeding, 85-DAS and 102-DAS. Our results indicated that E-O3 had no significant effects on leaf length, leaf width, leaf area, stomatal length and stomatal density for both Bt-SY63 and SY63. E-O3 increased the leaf thickness of Bt-SY63, but decreased that of SY63. O3 stress caused early swelling of the thylakoids of chloroplasts, a significant increase in the proportion of total plastoglobule area in the entire cell area (PCAP and a significant decrease in the proportion of total starch grain area in the entire cell area (SCAP, suggesting that E-O3 accelerated the leaf senescence of the two rice genotypes. Compared with SY63, E-O3 caused early swelling of the thylakoids of chloroplasts and more substantial breakdown of chloroplasts in Bt-SY63. CONCLUSIONS/SIGNIFICANCE: Our results suggest that the incorporation of cry1Ab/Ac into SY63 could induce unintentional changes in some parts of plant morphology and that O3 stress results in greater leaf damage to Bt-SY63 than to SY63, with the former coupled with higher O3 sensitivity in CCAP (the proportions of total chloroplast area in the entire cell area, PCAP and SCAP. This study provides valuable baseline information for the prospective

  16. 棉铃虫中肠氨肽酶 APN4与 Cry1Ac、Cry2Aa 结合能力的比较%Comparison of the binding affinity of the APN4 receptor in Helicoverpa armigera (Hübner) to the Cry1Ac and Cry2Aa insecticidal proteins

    Institute of Scientific and Technical Information of China (English)

    袁向东; 葛朝虹; 肖玉涛; 梁革梅

    2015-01-01

    Objectives] Bt (Bacillus thuringiensis) insecticidal proteins have been widely adopted to control agricultural pests because of their high target specificity. The binding of a Bt insecticidal protein to its specific receptor in the insect midgut plays a key role in the insecticidal action process. Aminopeptidase N (APN) is one of the major Bt protein receptors. To better characterize the molecular mechanism underlying the insecticidal activity of different Bt insecitcidal proteins, and lay the foundation for Bt resistance management and novel Bt insecticidal protein development, we analyzed the binding affinity of aminopeptidase N4 (APN4) to the Cry1Ac and Cry2Aa insecitcidal proteins in Helicoverpa armigera. [Methods] The binding affinity of aminopeptidase N4 (APN4) was assessed using ligand blot analysis and an ELISA binding assay, respectively. [Results] The results show that recombinant APN4 could bind to both Cry1Ac and Cry2A; their respective dissociation constants were 46.7 nmol/L and 26.5 nmol/L. [Conclusion] The results suggest that there was no significant difference in the binding affinity of APN4 to Cry1Ac and Cry2Aa in H. armigera.%【目的】 Bt 杀虫蛋白(Bacillus thuringiensis)具有高度的靶标特异性,已经被广泛用于农业害虫防治。Bt 杀虫蛋白要发挥杀虫活性,必须首先与其受体蛋白结合,氨肽酶 N(Aminopeptidase N)是一类重要的 Bt 受体蛋白。因此,分析该受体与 Bt 杀虫蛋白的结合能力,可为进一步明确不同 Bt 的分子作用机制、Bt 的抗性治理以及新 Bt 的开发应用等提供借鉴。【方法】本文利用 Ligand blot 和 Elisa 方法比较了棉铃虫 Helicoverpa armigera 中肠 APN4(Aminopeptidase N4,APN4)与 Cry1Ac、Cry2Aa 的结合能力。【结果】原核表达的 APN4片段与活化的 Cry1Ac、Cry2Aa 都可以结合,解离常数(Kd)分别是48.59 nmol/L和21.73 nmol/L。【结论】 APN4片段与 Cry1Ac、Cry2Aa 的结合能力

  17. Preparation of Monoclonal Antibody Against Bt Cry1Ac by Using Synthetic Peptide as Hapten%用人工合成多肽作为半抗原制备Bt Cry1Ac的单克隆抗体

    Institute of Scientific and Technical Information of China (English)

    胡小元; 张岐蜀; 段伟; 姜国华; 李玲

    2012-01-01

    为了制备Bt Cry1Ac特异性单克隆抗体(MAB),本试验从NCBI获得了Bt Cry1Ac蛋白的氨基酸序列,根据抗原性、亲水性和表位性分析选定Bt Cry1Ac特异性肽段进行人工合成,并将其偶联于匙孔血蓝蛋白(KLH)免疫动物,应用细胞融合技术制备了抗该肽段的杂交瘤细胞34株.通过ELISA和免疫印迹试验从中筛选出与Bt Cry1Ac天然蛋白产生特异性反应的单克隆抗体杂交瘤细胞株一株(6G9).ELISA和免疫印迹试验结果显示,该克隆株所分泌的MAB能对合成肽和Bt Cry1Ac产生特异性反应,而与同源的Bt Cry1Aa、Bt Cry1Ab天然蛋白均无交叉反应.通过对转基因棉花的ELISA检测结果表明,本试验所制备的Bt Cry1Ac单克隆抗体能够有效的区分常规棉和抗虫棉,并且能对其中的Bt Cry1Ac蛋白进行特异性的识别.%order to prepare monoclonal antibody Bt CrylAc, we got the amino acid sequence of Bt CrylAc protein from NCBI, and synthesized specific Bt CrylAc peptide, according to its antigenicity, hydro-philicity and accessibility on the basis of its structural features by computer assisted analysis. The peptide was linked with carrier keyhole limpet hemocyanin( KHL), and then used for immunized mouse as antigen. 34 strains of hybridoma, which can produce monoclonal antibodies to the peptide, have been obtained by cell fusion technique. One hybridoma strain (6G9), which was specific to natural Bt Cryl Ac was selected by indirect ELISA and Western blot. The result showed that the monoclonal antibody of hybridoma strain (6G9) can react specifically with the synthetic peptide and Bt CrylAc protein, but can not react with Bt CrylAa and Bt Cryl Ab proteins by ELISA and Western blot. This result of experiment showed that the monoclonal antibody of hybridoma strain(6C9)can distinguish transgenic Bt CrylAc cotton and general cotton by ELISA, and it can recognize specifically Bt CrylAc protein in cotton.

  18. Resistance of Trichoplusia ni to Bacillus thuringiensis Toxin Cry1Ac Is Independent of Alteration of the Cadherin-Like Receptor for Cry Toxins

    OpenAIRE

    Xin Zhang; Kasorn Tiewsiri; Wendy Kain; Lihua Huang; Ping Wang

    2012-01-01

    Alteration of binding sites for Bacillus thuringiensis (Bt) toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptida...

  19. 基因枪介导法获得转BtCry1Ac基因抗虫玉米植株的研究%Genetic Transformation of BtCry1Ac into Maize by Particle Bombardment

    Institute of Scientific and Technical Information of China (English)

    铁双贵; 柏松; 岳润清; 齐建双; 王延召; 孙静; 陈小洁; 田保明

    2012-01-01

    CrylA c gene was introduced into immature embryo callus using particle bombardment. After selection, transgenic plants were regenerated. Some of them were positive by PCR and immune test paper analysis, it was demonstrated that the Cry1 Ac gene had been intergraded into plants genome and expressed in transgenic plants. Bioassay results showed that T) generation transgenic plants had high resistance to the Asian corn borer.%利用基因枪介导法将含有Cry1Ac基因的质粒转入玉米愈伤组织,获得转Bt基因玉米植株,对所获得的转基因植株进行PCR分析和金标免疫试纸鉴定.结果表明,部分转化植株呈阳性,说明目的基因已经整合到玉米基因组中.将转基因植株自交获得T1代种子,对T1代植株进行田间抗虫鉴定,结果表明,与对照相比转基因玉米植株的抗虫活性明显强于非转基因植株.

  20. Increased long-flight activity triggered in beet armyworm by larval feeding on diet containing Cry1Ac protoxin.

    Directory of Open Access Journals (Sweden)

    Xing Fu Jiang

    Full Text Available Evaluating ecological safety and conducting pest risk analysis for transgenic crops are vitally important before their commercial planting. The beet armyworm, Spodoptera exigua, a long-distance migratory insect pest, is not a direct target of transgenic Cry1Ac-expressing cotton in China, but nevertheless it has recently become an important pest. Migrants leaving their natal field arrive in other appropriate habitat far away in a short time, often followed by larval outbreaks. S. exigua has low susceptibility to Cry1Ac. However, our results from laboratory experiments identified (i sublethal effects of Cry1Ac protoxin on larval development rate, larval and pupal weight, and adult lifetime fecundity, and (ii increased long-flight behavior triggered by Cry1Ac which may contribute to larval outbreaks elsewhere. No significant differences in larval mortality, pupation rate, adult emergence rate, longevity, pre-oviposition period, or oviposition period were observed between controls and larvae fed on artificial diet incorporating a low concentration of Cry1Ac protoxin. The negative sublethal effects on some developmental and reproductive traits and lack of effect on others suggest they do not contribute to the observed severity of S. exigua outbreaks after feeding on Cry1Ac cotton. Interestingly, the percentage of long fliers increased significantly when larvae were reared on diet containing either of two low-dose treatments of Cry1Ac, suggesting a possible increased propensity to disperse long distances triggered by Cry1Ac. We hypothesize that negative effects on development and reproduction caused by Cry1Ac in the diet are offset by increased flight propensity triggered by the poor food conditions, thereby improving the chances of escaping adverse local conditions before oviposition. Increased long-flight propensity in turn may amplify the area damaged by outbreak populations. This phenomenon might be common in other migratory insect pests receiving

  1. Downregulation and Mutation of a Cadherin Gene Associated with Cry1Ac Resistance in the Asian Corn Borer, Ostrinia furnacalis (Guenée

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    Tingting Jin

    2014-09-01

    Full Text Available Development of resistance in target pests is a major threat to long-term use of transgenic crops expressing Bacillus thuringiensis (Bt Cry toxins. To manage and/or delay the evolution of resistance in target insects through the implementation of effective strategies, it is essential to understand the basis of resistance. One of the most important mechanisms of insect resistance to Bt crops is the alteration of the interactions between Cry toxins and their receptors in the midgut. A Cry1Ac-selected strain of Asian corn borer (ACB, Ostrinia furnacalis, a key pest of maize in China, evolved three mutant alleles of a cadherin-like protein (OfCAD (MPR-r1, MPR-r2 and MPR-r3, which mapped within the toxin-binding region (TBR. Each of the three mutant alleles possessed two or three amino acid substitutions in this region, especially Thr1457→Ser. In highly resistant larvae (ACB-Ac200, MPR-r2 had a 26-amino acid residue deletion in the TBR, which resulted in reduced binding of Cry1Ac compared to the MPR from the susceptible strain, suggesting that the number of amino acid deletions influences the level of resistance. Furthermore, downregulation of OfCAD gene (ofcad transcription was observed in the Cry1Ac resistant strain, ACB-Ac24, suggesting that Cry1Ac resistance in ACB is associated with the downregulation of the transcript levels of the cadherin-like protein gene. The OfCAD identified from ACB exhibited a high degree of similarity to other members of the cadherin super-family in lepidopteran species.

  2. Expression of Cry1Ac in transgenic tobacco plants under the control of a wound-inducible promoter (AoPR1) isolated from Asparagus officinalis to control Heliothis virescens and Manduca sexta.

    Science.gov (United States)

    Gulbitti-Onarici, Selma; Zaidi, Mohsin Abbas; Taga, Ibrahim; Ozcan, Sebahattin; Altosaar, Illimar

    2009-07-01

    Expression of cry1Ac gene from Bacillus thuringiensis (Bt) was evaluated under the control of a wound-inducible AoPR1 promoter from Asparagus officinalis in transgenic tobacco plants. The leaves of transgenic plants were mechanically wounded to evaluate the activity of the AoPR1 promoter in driving the expression of Cry1Ac protein at the wound site. Our results indicate that mechanical wounding of transgenic plants was effective in inducing the expression of Cry1Ac protein. As a result of this induction, the accumulated levels of Cry1Ac protein increased during 6-72 h post-wounding period. The leaves of transgenic tobacco plants were evaluated for resistance against Heliothis virescens and Manduca sexta in insect bioassays in two different ways. The detached tobacco leaves were either fed directly to the insect larvae or they were first mechanically wounded followed by a 72 h post-wounding feeding period. Complete protection of mechanically wounded leaves of transgenic plants was observed within 24 h of the bioassay. The leaves of transgenic plants fed directly (without pre-wounding) to the larvae achieved the same level of protection between 24 and 72 h of the bioassay. PMID:19353306

  3. Binding and Oligomerization of Modified and Native Bt Toxins in Resistant and Susceptible Pink Bollworm.

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    Josue Ocelotl

    Full Text Available Insecticidal proteins from Bacillus thuringiensis (Bt are used extensively in sprays and transgenic crops for pest control, but their efficacy is reduced when pests evolve resistance. Better understanding of the mode of action of Bt toxins and the mechanisms of insect resistance is needed to enhance the durability of these important alternatives to conventional insecticides. Mode of action models agree that binding of Bt toxins to midgut proteins such as cadherin is essential for toxicity, but some details remain unresolved, such as the role of toxin oligomers. In this study, we evaluated how Bt toxin Cry1Ac and its genetically engineered counterpart Cry1AcMod interact with brush border membrane vesicles (BBMV from resistant and susceptible larvae of Pectinophora gossypiella (pink bollworm, a global pest of cotton. Compared with Cry1Ac, Cry1AcMod lacks 56 amino acids at the amino-terminus including helix α-1; previous work showed that Cry1AcMod formed oligomers in vitro without cadherin and killed P. gossypiella larvae harboring cadherin mutations linked with >1000-fold resistance to Cry1Ac. Here we found that resistance to Cry1Ac was associated with reduced oligomer formation and insertion. In contrast, Cry1AcMod formed oligomers in BBMV from resistant larvae. These results confirm the role of cadherin in oligomerization of Cry1Ac in susceptible larvae and imply that forming oligomers without cadherin promotes toxicity of Cry1AcMod against resistant P. gossypiella larvae that have cadherin mutations.

  4. Effects of transgenic Bt (Cry1Ab/Cry1Ac) rice on the population development of Plodia interpunctella%转Bt基因稻谷对印度谷螟生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    蒋海燕; 王振华; 华红霞; 高艮亮; 蔡万伦; 杨长举

    2011-01-01

    The effect of the transgenic Bt rice CrylAb/ CrylAc gene on the feeding of Plodia interpunctella ( Hlibner)on stored rice was investigated. Population parameters of P. Interpunctella were investigated after adding different ratios (70% , 50% , 30% , 10% ) of transgenic Bt rice flour into a conventional artificial diet at 30°C. And RH75%. The content of Bt protein in 3rd instar larva and the transgenic Bt rice grain was measured using the ELISA method. The results show that significant mortality of 1" instar larva was observed 72 h after feeding on Bt rice flour. Larval mortality rates and development time increased significantly as the content of transgenic Bt rice flour in the artificial diet increased. For research purposes, 2. 35 u.g/g was the optimal sub-lethal dose of Cryl Ab/Cryl Ac protein for P. Interpunctella.%为建立仓储阶段转Bt水稻安全性评价中靶标害虫抗性汰选研究体系,配制了含不同比例(70%,50%,30%,10%)转Bt基因(Cry1Ab/Cry IAbc)明辉63水稻谷粉(简称Bt谷粉)的人工饲料饲喂印度谷螟Plodiainterpunctella (Hübner),测定其对1~3龄幼虫在72 h内的急性毒力,及对印度谷螟种群生长发育的影响,并采用ELISA法检测转基因稻谷和末龄幼虫体内Bt蛋白含量.结果发现:4种比例人工饲料对幼虫的毒力作用均发生在取食48 h后,72 h后剂量效应明显.含Bt水稻较高比例的饲料对印度谷螟发育的负面效应明显:幼虫死亡率高,发育历期延长.Bt蛋白在幼虫体内含量与对应饲料中的含量基本成正比.综合考虑,将Bt杀虫蛋白含量2.35 μg/g作为转Bt基因稻谷对印度谷螟的亚致死剂量最为合适.

  5. Transgenic Cabbage Expressing Cry1Ac1 Does Not Affect the Survival and Growth of the Wolf Spider, Pardosa astrigera L. Koch (Araneae: Lycosidae)

    Science.gov (United States)

    Kim, Young-Joong; Lee, Joon-Ho; Harn, Chee Hark; Kim, Chang-Gi

    2016-01-01

    Both herbivores that consume transgenic crops and their predators can be exposed to insecticidal proteins expressed in those crops. We conducted a tritrophic bioassay to evaluate the ecotoxicological impacts that Bt cabbage (Brassica oleracea var. capitata) expressing Cry1Ac1 protein might have on the wolf spider (Pardosa astrigera), a non-target generalist predator. Enzyme-Linked Immunosorbent Assays indicated that protein levels were 4.61 ng g-1 dry weight in fruit flies (Drosophila melanogaster) fed with the transgenic cabbage and 1.86 ng g-1 dry weight in the wolf spiders that preyed upon them. We also compared the life history traits of spiders collected from Bt versus non-Bt cabbage and found no significant differences in their growth, survival, and developmental rates. Because Bt cabbage did not affect the growth of fruit flies, we conclude that any indirect effects that this crop had on the wolf spider were probably not mediated by prey quality. Therefore, exposure to Cry1Ac1 protein when feeding upon prey containing that substance from transgenic cabbage has only a negligible influence on those non-target predatory spiders. PMID:27055120

  6. Transgenic Cabbage Expressing Cry1Ac1 Does Not Affect the Survival and Growth of the Wolf Spider, Pardosa astrigera L. Koch (Araneae: Lycosidae).

    Science.gov (United States)

    Kim, Young-Joong; Lee, Joon-Ho; Harn, Chee Hark; Kim, Chang-Gi

    2016-01-01

    Both herbivores that consume transgenic crops and their predators can be exposed to insecticidal proteins expressed in those crops. We conducted a tritrophic bioassay to evaluate the ecotoxicological impacts that Bt cabbage (Brassica oleracea var. capitata) expressing Cry1Ac1 protein might have on the wolf spider (Pardosa astrigera), a non-target generalist predator. Enzyme-Linked Immunosorbent Assays indicated that protein levels were 4.61 ng g(-1) dry weight in fruit flies (Drosophila melanogaster) fed with the transgenic cabbage and 1.86 ng g(-1) dry weight in the wolf spiders that preyed upon them. We also compared the life history traits of spiders collected from Bt versus non-Bt cabbage and found no significant differences in their growth, survival, and developmental rates. Because Bt cabbage did not affect the growth of fruit flies, we conclude that any indirect effects that this crop had on the wolf spider were probably not mediated by prey quality. Therefore, exposure to Cry1Ac1 protein when feeding upon prey containing that substance from transgenic cabbage has only a negligible influence on those non-target predatory spiders.

  7. Characterization and functional analysis ofβ-1,3-galactosyltransferase involved in Cry1Ac resistance from Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-li; LIANG Ge-mei; GAO Xi-wu; CAO Guang-chun; GUO Yu-yuan

    2015-01-01

    Carbohydrate chains are the principal antigens by which Bacil us thuringiensis (Bt) identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cel s of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cel surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modiifcation of receptor proteins. It can indirectly inlfuence the function of Bt. The 1 950 bp ful-length cDNA encodingβ-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques (GAL-Harm, GenBank accession no.:GQ904195.1) with two potential N-glycosylation sites (157NNTI160 and 272NKTL275). Protein sequence alignments revealed that H. armigeraβ-1,3-galactosyltransferase shared high identity withβ-1,3-galactosyltransferase in other insect species. The expression level of theβ-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function ofβ-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1Ac enhanced the toxicity against the siRNA-treated larvae compared with non-siRNA-treated ones, which indicatedβ-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1Ac in H. armigera.

  8. Intranasal Coadministration of the Cry1Ac Protoxin with Amoebal Lysates Increases Protection against Naegleria fowleri Meningoencephalitis

    Science.gov (United States)

    Rojas-Hernández, Saúl; Rodríguez-Monroy, Marco A.; López-Revilla, Rubén; Reséndiz-Albor, Aldo A.; Moreno-Fierros, Leticia

    2004-01-01

    Cry1Ac protoxin has potent mucosal and systemic adjuvant effects on antibody responses to proteins or polysaccharides. In this work, we examined whether Cry1Ac increased protective immunity against fatal Naegleria fowleri infection in mice, which resembles human primary amoebic meningoencephalitis. Higher immunoglobulin G (IgG) than IgA anti-N. fowleri responses were elicited in the serum and tracheopulmonary fluids of mice immunized by the intranasal or intraperitoneal route with N. fowleri lysates either alone or with Cry1Ac or cholera toxin. Superior protection against a lethal challenge with 5 × 104 live N. fowleri trophozoites was achieved for immunization by the intranasal route. Intranasal immunization of N. fowleri lysates coadministered with Cry1Ac increased survival to 100%; interestingly, immunization with Cry1Ac alone conferred similar protection to that achieved with amoebal lysates alone (60%). When mice intranasally immunized with Cry1Ac plus lysates were challenged with amoebae, both IgG and IgA mucosal responses were rapidly increased, but only the increased IgG response persisted until day 60 in surviving mice. The brief rise in the level of specific mucosal IgA does not exclude the role that this isotype may play in the early defense against this parasite, since higher IgA responses were detected in nasal fluids of mice intranasally immunized with lysates plus either Cry1Ac or cholera toxin, which, indeed, were the treatments that provided the major protection levels. In contrast, serum antibody responses do not seem to be related to the protection level achieved. Both acquired and innate immune systems seem to play a role in host defense against N. fowleri infection, but further studies are required to elucidate the mechanisms involved in protective effects conferred by Cry1Ac, which may be a valuable tool to improve mucosal vaccines. PMID:15271892

  9. Domain III of the Bacillus thuringiensis delta-endotoxin Cry1Ac is involved in binding to Manduca sexta brush border membranes and to its purified aminopeptidase N

    NARCIS (Netherlands)

    Maagd, de R.A.; Bakker, P.L.; Masson, L.; Adang, M.J.; Sangadala, S.; Stiekema, W.; Bosch, D.

    1999-01-01

    Three types of binding assays were used to study the binding of Bacillus thuringiensis delta-endotoxin Cry1Ac to brush border membrane vesicle (BBMV) membranes and a purified putative receptor of the target insect Manduca sexta. Using hybrid proteins consisting of Cry1Ac and the related Cry1C protei

  10. The midgut cadherin-like gene is not associated with resistance to Bacillus thuringiensis toxin Cry1Ac in Plutella xylostella (L.).

    Science.gov (United States)

    Guo, Zhaojiang; Kang, Shi; Zhu, Xun; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhang, Youjun

    2015-03-01

    The Gram-positive bacterium Bacillus thuringiensis (Bt) produces Cry toxins that have been used to control important agricultural pests. Evolution of resistance in target pests threatens the effectiveness of these toxins when used either in sprayed biopesticides or in Bt transgenic crops. Although alterations of the midgut cadherin-like receptor can lead to Bt Cry toxin resistance in many insects, whether the cadherin gene is involved in Cry1Ac resistance of Plutella xylostella (L.) remains unclear. Here, we present experimental evidence that resistance to Cry1Ac or Bt var. kurstaki (Btk) in P. xylostella is not due to alterations of the cadherin gene. The bona fide P. xylostella cadherin cDNA sequence was cloned and analyzed, and comparisons of the cadherin cDNA sequence among susceptible and resistant P. xylostella strains confirmed that Cry1Ac resistance was independent of mutations in this gene. In addition, real-time quantitative PCR (qPCR) indicated that cadherin transcript levels did not significantly differ among susceptible and resistant P. xylostella strains. RNA interference (RNAi)-mediated suppression of cadherin gene expression did not affect larval susceptibility to Cry1Ac toxin. Furthermore, genetic linkage assays using four cadherin gDNA allelic biomarkers confirmed that the cadherin gene is not linked to resistance against Cry1Ac in P. xylostella. Taken together, our findings demonstrate that Cry1Ac resistance of P. xylostella is independent of the cadherin gene. PMID:25595643

  11. Effects of different brush border membrane vesicle isolation protocols on proteomic analysis of Cry1 Ac binding proteins from the midgut of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    Li-Zhen Chen; Ge-Mei Liang; Brian G.Rector; Jie Zhang; Kong-Ming Wu; Yu-Yuan Guo

    2008-01-01

    Brush border membrane vesicles(BBMV)isolated from insect midguts have been widely used to study CrylA binding proteins.Sample preparation is important in two-dimensional electrophoresis(2-DE),so to determine a suitable BBMV preparation method in Helicoverpa armigera for 2-DE,we compared three published BBMV preparation methods mostly used in sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).All mctllods yielded similar types and numbers of binding proteins,but in different quantifies.The Abdul.Rauf and Ellar protocol was the best of the three,but had limitations.Sufficient protein qu antity iS important for research involving limited numbers of insects,such as studies of insect resistance to Bacillus thuringiensis in the field.Consequently,we integrated the three BBMV isolation methods into a single protocol that yielded high quantities of BBMV proteins from H.armigera larval midguts.which proved suitable for 2-DE analysis.

  12. Potential factors impacting season-long expression of Cry1Ac in 13 commercial varieties of Bollgard® cotton

    Directory of Open Access Journals (Sweden)

    John J. Adamczyk, Jr.

    2001-11-01

    Full Text Available Thirteen commercial varieties of transgenic Cry1Ac Bacillus thuringiensis Berliner (Bt cotton were examined across two sites in 2000 for potential factors that impact endotoxin expression. In all cases, two varieties (NuCOTN 33B and DP 458B/RR, Delta and Pineland Co., Scott, MS expressed more Cry1Ac than the other 11 varieties in various plant structures. These two varieties share the same parental background (DP 5415. Furthermore, when the next generation of plants were tested in the greenhouse, the same varietal patterns were exhibited. These data strongly suggest that factors such as parental background had a stronger impact on the expression of Cry1Ac than the environment.

  13. Effects of transgenic Cry1Ac + CpTI cotton on non-target mealybug pest Ferrisia virgata and its predator Cryptolaemus montrouzieri.

    Directory of Open Access Journals (Sweden)

    Hongsheng Wu

    Full Text Available Recently, several invasive mealybugs (Hemiptera: Pseudococcidae have rapidly spread to Asia and have become a serious threat to the production of cotton including transgenic cotton. Thus far, studies have mainly focused on the effects of mealybugs on non-transgenic cotton, without fully considering their effects on transgenic cotton and trophic interactions. Therefore, investigating the potential effects of mealybugs on transgenic cotton and their key natural enemies is vitally important. A first study on the effects of transgenic cotton on a non-target mealybug, Ferrisia virgata (Cockerell (Hemiptera: Pseudococcidae was performed by comparing its development, survival and body weight on transgenic cotton leaves expressing Cry1Ac (Bt toxin + CpTI (Cowpea Trypsin Inhibitor with those on its near-isogenic non-transgenic line. Furthermore, the development, survival, body weight, fecundity, adult longevity and feeding preference of the mealybug predator Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae was assessed when fed F. virgata maintained on transgenic cotton. In order to investigate potential transfer of Cry1Ac and CpTI proteins via the food chain, protein levels in cotton leaves, mealybugs and ladybirds were quantified. Experimental results showed that F. virgata could infest this bivalent transgenic cotton. No significant differences were observed in the physiological parameters of the predator C. montrouzieri offered F. virgata reared on transgenic cotton or its near-isogenic line. Cry1Ac and CpTI proteins were detected in transgenic cotton leaves, but no detectable levels of both proteins were present in the mealybug or its predator when reared on transgenic cotton leaves. Our bioassays indicated that transgenic cotton poses a negligible risk to the predatory coccinellid C. montrouzieri via its prey, the mealybug F. virgata.

  14. Effects of Transgenic Cry1Ac + CpTI Cotton on Non-Target Mealybug Pest Ferrisia virgata and Its Predator Cryptolaemus montrouzieri

    Science.gov (United States)

    Wu, Hongsheng; Zhang, Yuhong; Liu, Ping; Xie, Jiaqin; He, Yunyu; Deng, Congshuang; De Clercq, Patrick; Pang, Hong

    2014-01-01

    Recently, several invasive mealybugs (Hemiptera: Pseudococcidae) have rapidly spread to Asia and have become a serious threat to the production of cotton including transgenic cotton. Thus far, studies have mainly focused on the effects of mealybugs on non-transgenic cotton, without fully considering their effects on transgenic cotton and trophic interactions. Therefore, investigating the potential effects of mealybugs on transgenic cotton and their key natural enemies is vitally important. A first study on the effects of transgenic cotton on a non-target mealybug, Ferrisia virgata (Cockerell) (Hemiptera: Pseudococcidae) was performed by comparing its development, survival and body weight on transgenic cotton leaves expressing Cry1Ac (Bt toxin) + CpTI (Cowpea Trypsin Inhibitor) with those on its near-isogenic non-transgenic line. Furthermore, the development, survival, body weight, fecundity, adult longevity and feeding preference of the mealybug predator Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) was assessed when fed F. virgata maintained on transgenic cotton. In order to investigate potential transfer of Cry1Ac and CpTI proteins via the food chain, protein levels in cotton leaves, mealybugs and ladybirds were quantified. Experimental results showed that F. virgata could infest this bivalent transgenic cotton. No significant differences were observed in the physiological parameters of the predator C. montrouzieri offered F. virgata reared on transgenic cotton or its near-isogenic line. Cry1Ac and CpTI proteins were detected in transgenic cotton leaves, but no detectable levels of both proteins were present in the mealybug or its predator when reared on transgenic cotton leaves. Our bioassays indicated that transgenic cotton poses a negligible risk to the predatory coccinellid C. montrouzieri via its prey, the mealybug F. virgata. PMID:24751821

  15. Genetic mapping of Bt-toxin binding proteins in a Cry1A-toxin resistant strain of diamondback moth Plutella xylostella.

    Science.gov (United States)

    Baxter, Simon W; Zhao, Jian-Zhou; Shelton, Anthony M; Vogel, Heiko; Heckel, David G

    2008-02-01

    A major mechanism of resistance to Bacillus thuringiensis (Bt) toxins in Lepidoptera is a reduction of toxin binding to sites in the midgut membrane. Genetic studies of three different species have shown that mutations in a candidate Bt receptor, a 12-cadherin-domain protein, confer Cry1A toxin resistance. Despite a similar resistance profile in a fourth lepidopteran species, Plutella xylostella, we have previously shown that the cadherin orthologue maps to a different linkage group (LG8) than Cry1Ac resistance (LG22). Here we tested the hypothesis that mutations in other genes encoding candidate Bt-binding targets could be responsible for Bt resistance, by mapping eight aminopeptidases, an alkaline phosphatase (ALP), an intestinal mucin, and a P252 glycoprotein with respect to the 29 AFLP marked linkage groups in a P. xylostella cross segregating for Cry1Ac resistance. A homologue of the Caenorhabditis elegans Bt resistance gene bre-2 was also mapped. None of the genes analysed were on the same chromosome containing the Cry1Ac resistance locus, eliminating them as candidate resistance genes in the parental resistant strain SC1. Although this finding excludes cis-acting mutations in these genes as causing resistance in this strain, one or more of the expressed proteins may still bind Cry1Ac toxin, and post-translational modifications could affect this binding and thereby exert a trans-acting effect on resistance. PMID:18207074

  16. Evaluation of Cytotoxic and Antimicrobial Effects of Two Bt Cry Proteins on a GMO Safety Perspective

    Directory of Open Access Journals (Sweden)

    Davi Felipe Farias

    2014-01-01

    Full Text Available Studies have contested the innocuousness of Bacillus thuringiensis (Bt Cry proteins to mammalian cells as well as to mammals microbiota. Thus, this study aimed to evaluate the cytotoxic and antimicrobial effects of two Cry proteins, Cry8Ka5 (a novel mutant protein and Cry1Ac (a widely distributed protein in GM crops. Evaluation of cyto- and genotoxicity in human lymphocytes was performed as well as hemolytic activity coupled with cellular membrane topography analysis in mammal erythrocytes. Effects of Cry8Ka5 and Cry1Ac upon Artemia sp. nauplii and upon bacteria and yeast growth were assessed. The toxins caused no significant effects on the viability (IC50>1,000 µg/mL or to the cellular DNA integrity of lymphocytes (no effects at 1,000 µg/mL. The Cry8Ka5 and Cry1Ac proteins did not cause severe damage to erythrocytes, neither with hemolysis (IC50>1,000 µg/mL nor with alterations in the membrane. Likewise, the Cry8Ka5 and Cry1Ac proteins presented high LC50 (755.11 and >1,000 µg/mL, resp. on the brine shrimp lethality assay and showed no growth inhibition of the microorganisms tested (MIC>1,000 µg/mL. This study contributed with valuable information on the effects of Cry8Ka5 and Cry1Ac proteins on nontarget organisms, which reinforce their potential for safe biotechnological applications.

  17. Acquirement and Molecular Identification of Transgenic Insect-resistant Corn Expressing Cry1Ac-w Gene%转Cry1Ac-w基因抗虫玉米的获得及分子鉴定

    Institute of Scientific and Technical Information of China (English)

    燕树锋; 铁双贵; 岳润清; 韩小花; 齐建双; 卢彩霞

    2015-01-01

    为将改造合成的抗虫基因(Cry1Ac-w)导入玉米基因组,以玉米杂交组合PA× PB的胚性愈伤组织为外植体,用双丙氨磷作为抗性愈伤组织的筛选剂,通过农杆菌介导法获得了82个再生植株.经标记基因(bar)和目的基因(Cry1 Ac-w)的PCR检测,其中19株为阳性,即为推断的转Cry1Ac-w基因抗虫玉米.对其中2株(w1和W2)进行目的基因单酶切的Southern杂交分析,发现w1和w2分别为单位点和双位点插入,这也进一步证实目的基因已经整合入玉米基因组中.用Bt-Cry1 Ab/Ac金标免疫试纸条进行蛋白质表达的检测,初步证实目标Cry1Ac-w蛋白在玉米中得到表达.

  18. Inheritance Patterns, Dominance and Cross-Resistance of Cry1Ab- and Cry1Ac-Selected Ostrinia furnacalis (Guenée

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    Tiantao Zhang

    2014-09-01

    Full Text Available Two colonies of Asian corn borer, Ostrinia furnacalis (Guenée, artificially selected from a Bt-susceptible colony (ACB-BtS for resistance to Cry1Ab (ACB-AbR and Cry1Ac (ACB-AcR toxins, were used to analyze inheritance patterns of resistance to Cry1 toxins. ACB-AbR and ACB-AcR evolved significant levels of resistance, with resistance ratios (RR of 39-fold and 78.8-fold to Cry1Ab and Cry1Ac, respectively. The susceptibility of ACB-AbR larvae to Cry1Ac and Cry1F toxins, which had not previously been exposed, were significantly reduced, being >113-fold and 48-fold, respectively. Similarly, susceptibility of ACB-AcR larvae to Cry1Ab and Cry1F were also significantly reduced (RR > nine-fold, RR > 18-fold, respectively, indicating cross-resistance among Cry1Ab, Cry1Ac, and Cry1F toxins. However, ACB-AbR and ACB-AcR larvae were equally susceptible to Cry1Ie as were ACB-BtS larvae, indicating no cross-resistance between Cry1Ie and Cry1Ab or Cry1Ac toxins; this may provide considerable benefits in preventing or delaying the evolution of resistance in ACB to Cry1Ab and Cry1Ac toxins. Backcrossing studies indicated that resistance to Cry1Ab toxin was polygenic in ACB-AbR, but monogenic in ACB-AcR, whilst resistance to Cry1Ac toxin was primarily monogenic in both ACB-AbR and ACB-AcR, but polygenic as resistance increased.

  19. Enhancement of Bacillus thuringiensis insecticidal activity by combining Cry1Ac and bi-functional toxin HWTX-XI from spider.

    Science.gov (United States)

    Sun, Yunjun; Fu, Zujiao; He, Xiaohong; Yuan, Chunhua; Ding, Xuezhi; Xia, Liqiu

    2016-03-01

    In order to assess the potency of bi-functional HWTX-XI toxin from spider Ornithoctonus huwena in improving the insecticidal activity of Bacillus thuringiensis, a fusion gene of cry1Ac and hwtx-XI was constructed and expressed in an acrystalliferous B. thuringiensis strain Cry(-)B. Western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kDa Cry1Ac-HWTX-XI fusion protein and produce parasporal inclusions during sporulation. Bioassay using the larvae of Helicoverpa armigera and Spodoptera exigua showed that the Cry1Ac-HWTX-XI fusion was more toxic than the control Cry1Ac protoxin, as revealed by 95% lethal concentration. Our study indicated that the HWTX-XI from spider might be a candidate for enhancing the toxicity of B. thuringiensis products.

  20. Enhancement of Bacillus thuringiensis insecticidal activity by combining Cry1Ac and bi-functional toxin HWTX-XI from spider.

    Science.gov (United States)

    Sun, Yunjun; Fu, Zujiao; He, Xiaohong; Yuan, Chunhua; Ding, Xuezhi; Xia, Liqiu

    2016-03-01

    In order to assess the potency of bi-functional HWTX-XI toxin from spider Ornithoctonus huwena in improving the insecticidal activity of Bacillus thuringiensis, a fusion gene of cry1Ac and hwtx-XI was constructed and expressed in an acrystalliferous B. thuringiensis strain Cry(-)B. Western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kDa Cry1Ac-HWTX-XI fusion protein and produce parasporal inclusions during sporulation. Bioassay using the larvae of Helicoverpa armigera and Spodoptera exigua showed that the Cry1Ac-HWTX-XI fusion was more toxic than the control Cry1Ac protoxin, as revealed by 95% lethal concentration. Our study indicated that the HWTX-XI from spider might be a candidate for enhancing the toxicity of B. thuringiensis products. PMID:25721170

  1. The role of β18-β19 loop structure in insecticidal activity of Cry1Ac toxin from Bacillus thuringiensis

    Institute of Scientific and Technical Information of China (English)

    XIA LiQiu; WANG FaXiang; DING XueZhi; ZHAO XinMin; FU ZuJiao; QUAN MeiFang; YU ZiNiu

    2008-01-01

    The β18-β19 loop in domain Ⅲ of Cry1Ac toxin is unique among Bacillus thuringiensis Cry proteins. In this study, the role of the loop structure in insecticidal activity of Cry1Ac toxin was investigated. Alanine scanning mutations within the loop were initially generated and most mutants were over-expressed and reduced toxicity at different degrees, except mutant N546A that showed almost 2 times enhanced toxicity against Helicoverpa armigera larvae. Further mutagenic analysis of N546 re-vealed that a charged amino acid in this position would cause very unfavorable influence on insecti-cidal activity. In addition, the deletion of N546 led to protein instability because of destruction of the loop integrity. Besides, mutant W544F was much more toxic than W544Y, indicating that hydrophobic nature of the position was important for maintaining the stability and activity of Cry1Ac protein. These findings are the first biological evidence for a structural function of β18-β19 loop in insecticidal activity of the Cry1Ac toxin.

  2. Non-recessive Bt toxin resistance conferred by an intracellular cadherin mutation in field-selected populations of cotton bollworm.

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    Haonan Zhang

    Full Text Available Transgenic crops producing Bacillus thuringiensis (Bt toxins have been planted widely to control insect pests, yet evolution of resistance by the pests can reduce the benefits of this approach. Recessive mutations in the extracellular domain of toxin-binding cadherin proteins that confer resistance to Bt toxin Cry1Ac by disrupting toxin binding have been reported previously in three major lepidopteran pests, including the cotton bollworm, Helicoverpa armigera. Here we report a novel allele from cotton bollworm with a deletion in the intracellular domain of cadherin that is genetically linked with non-recessive resistance to Cry1Ac. We discovered this allele in each of three field-selected populations we screened from northern China where Bt cotton producing Cry1Ac has been grown intensively. We expressed four types of cadherin alleles in heterologous cell cultures: susceptible, resistant with the intracellular domain mutation, and two complementary chimeric alleles with and without the mutation. Cells transfected with each of the four cadherin alleles bound Cry1Ac and were killed by Cry1Ac. However, relative to cells transfected with either the susceptible allele or the chimeric allele lacking the intracellular domain mutation, cells transfected with the resistant allele or the chimeric allele containing the intracellular domain mutation were less susceptible to Cry1Ac. These results suggest that the intracellular domain of cadherin is involved in post-binding events that affect toxicity of Cry1Ac. This evidence is consistent with the vital role of the intracellular region of cadherin proposed by the cell signaling model of the mode of action of Bt toxins. Considered together with previously reported data, the results suggest that both pore formation and cell signaling pathways contribute to the efficacy of Bt toxins.

  3. MAPK Signaling Pathway Alters Expression of Midgut ALP and ABCC Genes and Causes Resistance to Bacillus thuringiensis Cry1Ac Toxin in Diamondback Moth

    OpenAIRE

    Zhaojiang Guo; Shi Kang; Defeng Chen; Qingjun Wu; Shaoli Wang; Wen Xie; Xun Zhu; Baxter, Simon W.; Xuguo Zhou; Juan Luis Jurat-Fuentes; Youjun Zhang

    2015-01-01

    Insecticidal crystal toxins derived from the soil bacterium Bacillus thuringiensis (Bt) are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. However, large-scale use of Bt has led to field-evolved resistance in several lepidopteran pests. Resistance to Bt Cry1Ac toxin in the diamondback moth, Plutella xylostella (L.), was previously mapped to a multigenic resistance locus (BtR-1). Here, we assembled the 3.15 Mb BtR-1 locus and found high-level resis...

  4. Resistance of Trichoplusia ni Populations Selected by Bacillus thuringiensis Sprays to Cotton Plants Expressing Pyramided Bacillus thuringiensis Toxins Cry1Ac and Cry2Ab

    Science.gov (United States)

    Kain, Wendy; Song, Xiaozhao; Janmaat, Alida F.; Zhao, Jian-Zhou; Myers, Judith; Shelton, Anthony M.

    2014-01-01

    Two populations of Trichoplusia ni that had developed resistance to Bacillus thuringiensis sprays (Bt sprays) in commercial greenhouse vegetable production were tested for resistance to Bt cotton (BollGard II) plants expressing pyramided Cry1Ac and Cry2Ab. The T. ni colonies resistant to Bacillus thuringiensis serovar kurstaki formulations were not only resistant to the Bt toxin Cry1Ac, as previously reported, but also had a high frequency of Cry2Ab-resistant alleles, exhibiting ca. 20% survival on BollGard II foliage. BollGard II-resistant T. ni strains were established by selection with BollGard II foliage to further remove Cry2Ab-sensitive alleles in the T. ni populations. The BollGard II-resistant strains showed incomplete resistance to BollGard II, with adjusted survival values of 0.50 to 0.78 after 7 days. The resistance to the dual-toxin cotton plants was conferred by two genetically independent resistance mechanisms: one to Cry1Ac and one to Cry2Ab. The 50% lethal concentration of Cry2Ab for the resistant strain was at least 1,467-fold that for the susceptible T. ni strain. The resistance to Cry2Ab in resistant T. ni was an autosomally inherited, incompletely recessive monogenic trait. Results from this study indicate that insect populations under selection by Bt sprays in agriculture can be resistant to multiple Bt toxins and may potentially confer resistance to multitoxin Bt crops. PMID:25480752

  5. Transformation and evaluation of Cry1Ac+Cry2A and GTGene in Gossypium hirsutum L.

    Directory of Open Access Journals (Sweden)

    Agung Nugroho Puspito

    2015-11-01

    Full Text Available More than 50 countries around the globe cultivate cotton on a large scale. It is a major cash crop of Pakistan and is considered white gold because it is highly important to the economy of Pakistan. In addition to its importance, cotton cultivation faces several problems, such as insect pests, weeds, and viruses. In the past, insects have been controlled by insecticides, but this method caused a severe loss to the economy. However, conventional breeding methods have provided considerable breakthroughs in the improvement of cotton, but it also has several limitations. In comparison with conventional methods, biotechnology has the potential to create genetically modified plants that are environmentally safe and economically viable. In this study, a local cotton variety VH 289 was transformed with two Bt genes (Cry1Ac and Cry2A and a herbicide resistant gene (cp4 EPSPS using the Agrobacterium mediated transformation method. The constitutive CaMV 35S promoter was attached to the genes taken from Bacillus thuringiensis (Bt and to an herbicide resistant gene during cloning, and this promoter was used for the expression of the genes in cotton plants. This construct was used to develop the Glyphosate Tolerance Gene (GTGene for herbicide tolerance and insecticidal gene (Cry1Ac and Cry2A for insect tolerance in the cotton variety VH 289. The transgenic cotton variety performed 85% better compared with the non-transgenic variety. The study results suggest that farmers should use the transgenic cotton variety for general cultivation to improve the production of cotton.

  6. Toxicological Evaluation of a Potential Immunosensitizer for Use as a Mucosal Adjuvant—Bacillus thuringiensis Cry1Ac Spore-Crystals: A Possible Inverse Agonist that Deserves Further Investigation

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    Bélin Poletto Mezzomo

    2015-12-01

    Full Text Available In addition to their applicability as biopesticides, Bacillus thuringiensis (Bt Cry1Ac spore-crystals are being researched in the immunology field for their potential as adjuvants in mucosal and parenteral immunizations. We aimed to investigate the hematotoxicity and genotoxicity of Bt spore-crystals genetically modified to express Cry1Ac individually, administered orally (p.o. or with a single intraperitoneal (i.p. injection 24 h before euthanasia, to simulate the routes of mucosal and parenteral immunizations in Swiss mice. Blood samples were used to perform hemogram, and bone marrow was used for the micronucleus test. Cry1Ac presented cytotoxic effects on erythroid lineage in both routes, being more severe in the i.p. route, which also showed genotoxic effects. The greater severity noted in this route, mainly at 6.75 mg/kg, as well as the intermediate effects at 13.5 mg/kg, and the very low hematotoxicity at 27 mg/kg, suggested a possible inverse agonism. The higher immunogenicity for the p.o. route, particularly at 27 mg/kg, suggested that at this dose, Cry 1Ac could potentially be used as a mucosal adjuvant (but not in parenteral immunizations, due to the genotoxic effects observed. This potential should be investigated further, including making an evaluation of the proposed inverse agonism and carrying out cytokine profiling.

  7. Toxicological Evaluation of a Potential Immunosensitizer for Use as a Mucosal Adjuvant--Bacillus thuringiensis Cry1Ac Spore-Crystals: A Possible Inverse Agonist that Deserves Further Investigation.

    Science.gov (United States)

    Mezzomo, Bélin Poletto; Miranda-Vilela, Ana Luisa; Grisolia, Cesar Koppe

    2015-12-01

    In addition to their applicability as biopesticides, Bacillus thuringiensis (Bt) Cry1Ac spore-crystals are being researched in the immunology field for their potential as adjuvants in mucosal and parenteral immunizations. We aimed to investigate the hematotoxicity and genotoxicity of Bt spore-crystals genetically modified to express Cry1Ac individually, administered orally (p.o.) or with a single intraperitoneal (i.p.) injection 24 h before euthanasia, to simulate the routes of mucosal and parenteral immunizations in Swiss mice. Blood samples were used to perform hemogram, and bone marrow was used for the micronucleus test. Cry1Ac presented cytotoxic effects on erythroid lineage in both routes, being more severe in the i.p. route, which also showed genotoxic effects. The greater severity noted in this route, mainly at 6.75 mg/kg, as well as the intermediate effects at 13.5 mg/kg, and the very low hematotoxicity at 27 mg/kg, suggested a possible inverse agonism. The higher immunogenicity for the p.o. route, particularly at 27 mg/kg, suggested that at this dose, Cry 1Ac could potentially be used as a mucosal adjuvant (but not in parenteral immunizations, due to the genotoxic effects observed). This potential should be investigated further, including making an evaluation of the proposed inverse agonism and carrying out cytokine profiling. PMID:26690217

  8. Effect of crop plants on fitness costs associated with resistance to Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in cabbage loopers

    Science.gov (United States)

    Wang, Ran; Tetreau, Guillaume; Wang, Ping

    2016-01-01

    Fitness costs associated with resistance to Bacillus thuringiensis (Bt) toxins critically impact the development of resistance in insect populations. In this study, the fitness costs in Trichoplusia ni strains associated with two genetically independent resistance mechanisms to Bt toxins Cry1Ac and Cry2Ab, individually and in combination, on four crop plants (cabbage, cotton, tobacco and tomato) were analyzed, in comparison with their near-isogenic susceptible strain. The net reproductive rate (R0) and intrinsic rate of increase (r) of the T. ni strains, regardless of their resistance traits, were strongly affected by the host plants. The ABCC2 gene-linked mechanism of Cry1Ac resistance was associated with relatively low fitness costs, while the Cry2Ab resistance mechanism was associated with higher fitness costs. The fitness costs in the presence of both resistance mechanisms in T. ni appeared to be non-additive. The relative fitness of Bt-resistant T. ni depended on the specific resistance mechanisms as well as host plants. In addition to difference in survivorship and fecundity, an asynchrony of adult emergence was observed among T. ni with different resistance mechanisms and on different host plants. Therefore, mechanisms of resistance and host plants available in the field are both important factors affecting development of Bt resistance in insects. PMID:26868936

  9. Pretreatment with Cry1Ac Protoxin Modulates the Immune Response, and Increases the Survival of Plasmodium-Infected CBA/Ca Mice

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    Martha Legorreta-Herrera

    2010-01-01

    Full Text Available Malaria is a major global health problem that kills 1-2 million people each year. Despite exhaustive research, naturally acquired immunity is poorly understood. Cry1A proteins are potent immunogens with adjuvant properties and are able to induce strong cellular and humoral responses. In fact, it has been shown that administration of Cry1Ac protoxin alone or with amoebic lysates induces protection against the lethal infection caused by the protozoa Naegleria fowleri. In this work, we studied whether Cry1Ac is able to activate the innate immune response to induce protection against Plasmodium berghei ANKA (lethal and P. chabaudi AS (nonlethal parasites in CBA/Ca mice. Treatment with Cry1Ac induced protection against both Plasmodium species in terms of reduced parasitaemia, longer survival time, modulation of pro- and anti-inflammatory cytokines, and increased levels of specific antibodies against Plasmodium. Understanding how to boost innate immunity to Plasmodium infection should lead to immunologically based intervention strategies.

  10. Pretreatment with Cry1Ac Protoxin Modulates the Immune Response, and Increases the Survival of Plasmodium-Infected CBA/Ca Mice

    Science.gov (United States)

    Legorreta-Herrera, Martha; Oviedo Meza, Rodrigo; Moreno-Fierros, Leticia

    2010-01-01

    Malaria is a major global health problem that kills 1-2 million people each year. Despite exhaustive research, naturally acquired immunity is poorly understood. Cry1A proteins are potent immunogens with adjuvant properties and are able to induce strong cellular and humoral responses. In fact, it has been shown that administration of Cry1Ac protoxin alone or with amoebic lysates induces protection against the lethal infection caused by the protozoa Naegleria fowleri. In this work, we studied whether Cry1Ac is able to activate the innate immune response to induce protection against Plasmodium berghei ANKA (lethal) and P. chabaudi AS (nonlethal) parasites in CBA/Ca mice. Treatment with Cry1Ac induced protection against both Plasmodium species in terms of reduced parasitaemia, longer survival time, modulation of pro- and anti-inflammatory cytokines, and increased levels of specific antibodies against Plasmodium. Understanding how to boost innate immunity to Plasmodium infection should lead to immunologically based intervention strategies. PMID:20300584

  11. Biosafety assessment of transgenic Bt cotton on model animals

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    Sadia Bano

    2016-05-01

    Full Text Available Abstract Background: To know the effects of transgenic crops on soil microorganisms, animals and other expected hazards due to the introduction of GM crops into the environment is critical both scientifically and environmentally. The work was conducted to study the effect of insecticidal Bt protein on Rats and Earthworms. Methods: For this purpose, animals like rat and soil organisms like Earthworm were selected. Rats were selected on the basis of its 95% homology on genomic, cellular and enzymatic level with human while earthworm were preferred on the basis of their direct contact with soil to evaluate the impact of Bt (Cry1AC crop field soil on earthworm, secreted by root exudates of Bt cotton. Several physical, molecular, biochemical and histological analyses were performed on both Rats/Earthworms fed on standard diet (control group as well containing Bt protein (experimental group. Results: Molecular analyses such as immune Dot blot, SDS-PAGE, ELISA and PCR, confirmed the absence of Cry1Ac protein in blood and urine samples of rats, which were fed with Bt protein in their diet. Furthermore, histological studies showed that there was no difference in cellular architecture in liver, heart, kidney and intestine of Bt and non-Bt diet fed rats. To see the effect of Bt on earthworm two different groups were studied, one with transgenic plant field soil supplemented with grinded leaves of cotton and second group with non-Bt field soil. Conclusions: No lethal effects of transgenic Bt protein on the survival of earthworm and rats were observed. Bradford assay, Dipstick assay ELISA demonstrated the absence of Cry1Ac protein in the mid-gut epithelial tissue of earthworm. The results of present study will be helpful in successful deployment and commercial release of genetically modified crop in Pakistan.

  12. Arthropods biodiversity index in Bollgard (R) cotton (CRy1Ac) in Brazil

    OpenAIRE

    Thomazoni, D.; Ferreira Soria, M.; Degrande, P.E.; Faccenda, O.; Silvie, Pierre

    2013-01-01

    Shannon-Wiener's diversity index (SWI) was used under untreated conditions of a cotton field during the 2006/2007 crop season in the Cerrado region, Brazil. Comparison was carried out between the transgenic NuOpal (R) (BollgarD (R))(Cry1Ac) and the non-transgenic isogenic variety DeltaOpal (R). SWI was calculated for target pests, non-target herbivores and predators groups. Two sampling methods were used: whole plant observation and beat sheet. As expected, the mean number of target pests, es...

  13. Uptake and transfer of a Bt toxin by a Lepidoptera to its eggs and effects on its offspring.

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    Débora Pires Paula

    Full Text Available Research on non-target effects of transgenic crop plants has focused primarily on bitrophic, tritrophic and indirect effects of entomotoxins from Bacillus thuringiensis, but little work has considered intergenerational transfer of Cry proteins. This work reports a lepidopteran (Chlosyne lacinia taking up a Bt entomotoxin when exposed to sublethal or low concentrations, transferring the entomotoxin to eggs, and having adverse effects on the first filial generation (F1 offspring. Two bioassays were conducted using a sublethal concentration of toxin (100.0 ng/µl Cry1Ac for adults and a concentration equal to the LC10 (2.0 ng/µl Cry1Ac for larvae. Cry1Ac is the most common entomotoxin expressed in Bt cotton in Brazil. In the adult diet bioassay there was no adverse effect on the parental generation (P0 adults, but the F1 larvae had higher mortality and longer development time compared to F1 larvae of parents that did not ingest Cry1Ac. For the 3rd instar larvae, there was no measurable effect on the P0 larvae, pupae and adults, but the F1 larvae had higher mortality and longer development time. Using chemiluminescent Western Blot, Cry1Ac was detected in F1 eggs laid by P0 butterflies from both bioassays. Our study indicates that, at least for this species and these experimental conditions, a ∼65 kDa insecticidal protein can be taken up and transferred to descendants where it can increase mortality and development time.

  14. Resistance to Anticarsia gemmatalis Hübner (Lepidoptera, Noctuidae in transgenic soybean (Glycine max (L. Merrill Fabales, Fabaceae cultivar IAS5 expressing a modified Cry1Ac endotoxin

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    Milena Schenkel Homrich

    2008-01-01

    Full Text Available Somatic embryos of the commercial soybean (Glycine max cultivar IAS5 were co-transformed using particle bombardment with a synthetic form of the Bacillus thuringiensis delta-endotoxin crystal protein gene cry1Ac, the beta-glucuronidase reporter gene gusA and the hygromycin resistance gene hpt. Hygromycin-resistant tissues were proliferated individually to give rise to nine sets of clones corresponding to independent transformation events. The co-bombardment resulted in a co-transformation efficiency of 44%. Many histodifferentiated embryos and 30 well-developed plants were obtained. Twenty of these plants flowered and fourteen set seeds. The integration and expression of the cry1Ac, gusA and hpt transgenes into the genomes of a sample of transformed embryos and all T0, T1, T2 and T3 plants were confirmed by Gus activity, PCR, Southern and western blot, and ELISA techniques. Two T0 plants out of the seven co-transformed plants produced seeds and were analyzed for patterns of integration and inheritance until the T3 generation. Bioassays indicated that the transgenic plants were highly toxic to the velvetbean caterpillar Anticarsia gemmatalis, thus offering a potential for effective insect resistance in soybean.

  15. Cross-resistance and inheritance of resistance to Bacillus thuringiensis toxin Cry1Ac in diamondback moth (Plutella xylostella L) from lowland Malaysia.

    Science.gov (United States)

    Sayyed, A H; Wright, D J

    2001-05-01

    A field population of Plutella xylostella from Malaysia (SERD4) was divided into five sub-populations and four were selected (G2-G5) with the Bacillus thuringiensis insecticidal crystal (Cry) toxins Cry1Ac, Cry1Ab, Cry1Ca and Cry1Da. Bioassay at G6 gave resistance ratios of 88, 5, 2 and 3 for Cry1Ac, Cry1Ab, Cry1Ca and Cry1Da respectively compared with the unselected sub-population (UNSEL-SERD4). The Cry1Ac-selected population showed little cross-resistance to Cry1Ab, Cry1Ca and Cry1Da, (3-, 2- and 3-fold compared with UNSEL-SERD4), whereas the Cry1Ab-SEL sub-population showed marked cross-resistance to Cry1Ac (40-fold), much greater than Cry1Ab itself. In contrast, the Cry1Ca- and Cry1Da-SEL sub-population showed little if any cross-resistance to Cry1Ac and Cry1Ab. The mode of inheritance of resistance to Cry1Ac was examined in Cry1Ac-selected SERD4 by standard reciprocal crosses and back-crosses using a laboratory insecticide-susceptible population (ROTH). Logit regression analysis of F1 reciprocal crosses indicated that resistance to Cry1Ac was inherited as an incompletely dominant trait. At the highest dose of Cry1Ac tested, resistance was recessive, while at the lowest dose it was almost completely dominant. The F2 progeny from a back-cross of F1 progeny with ROTH were tested with a concentration of Cry1Ac that would kill 100% of ROTH. The mortality ranged between 50 and 95% in seven families of back-cross progeny, which indicated that more than one allele on separate loci were responsible for resistance to Cry1Ac. PMID:11374157

  16. Susceptibility of legume pod borer (LPB), Maruca vitrata to delta-endotoxins of Bacillus thuringiensis (Bt) in Taiwan.

    Science.gov (United States)

    Srinivasan, R

    2008-01-01

    Baseline susceptibility of legume pod borer (LPB) to the insecticidal crystal proteins (ICPs) from Bacillus thuringiensis, viz, Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ca and Cry2Aa was assessed in Taiwan. Insect bioassays were performed by incorporating the Bt delta-endotoxins into the LPB artificial diet. The efficacy of different Bt delta-endotoxins against second instar larvae of LPB showed that the toxin Cry1Ab was the most potent toxin (LC(50) 0.207ppm), followed by Cry1Ca, Cry1Aa, Cry2Aa and Cry1Ac in descending order, with LC(50)s 0.477ppm, 0.812ppm, 1.058ppm and 1.666ppm, respectively. Hence, Cry1Ab and/or Cry1Ca toxins would provide effective control of early larval stages of LPB.

  17. Single amino acid insertions in extracellular loop 2 of Bombyx mori ABCC2 disrupt its receptor function for Bacillus thuringiensis Cry1Ab and Cry1Ac but not Cry1Aa toxins.

    Science.gov (United States)

    Tanaka, Shiho; Miyamoto, Kazuhisa; Noda, Hiroaki; Endo, Haruka; Kikuta, Shingo; Sato, Ryoichi

    2016-04-01

    In a previous report, seven Cry1Ab-resistant strains were identified in the silkworm, Bombyx mori; these strains were shown to have a tyrosine insertion at position 234 in extracellular loop 2 of the ABC transporter C2 (BmABCC2). This insertion was confirmed to destroy the receptor function of BmABCC2 and confer the strains resistance against Cry1Ab and Cry1Ac. However, these strains were susceptible to Cry1Aa. In this report, we examined the mechanisms of the loss of receptor function of the transporter by expressing mutations in Sf9 cells. After replacement of one or two of the five amino acid residues in loop 2 of the susceptible BmABCC2 gene [BmABCC2_S] with alanine, cells still showed susceptibility, retaining the receptor function. Five mutants with single amino acid insertions at position 234 in BmABCC2 were also generated, resulting in loop 2 having six amino acids, which corresponds to replacing the tyrosine insertion in the resistant BmABCC2 gene [BmABCC2_R(+(234)Y)] with another amino acid. All five mutants exhibited loss of function against Cry1Ab and Cry1Ac. These results suggest that the amino acid sequence in loop 2 is less important than the loop size (five vs. six amino acids) or loop structure for Cry1Ab and Cry1Ac activity. Several domain-swapped mutant toxins were then generated among Cry1Aa, Cry1Ab, and Cry1Ac, which are composed of three domains. Swapped mutants containing domain II of Cry1Ab or Cry1Ac did not kill Sf9 cells expressing BmABCC2_R(+(234)Y), suggesting that domain II of the Cry toxin is related to the interaction with the receptor function of BmABCC2. This also suggests that different reactions against Bt-toxins in some B. mori strains, that is, Cry1Ab resistance or Cry1Aa susceptibility, are attributable to structural differences in domain II of Cry1A toxins.

  18. Single amino acid insertions in extracellular loop 2 of Bombyx mori ABCC2 disrupt its receptor function for Bacillus thuringiensis Cry1Ab and Cry1Ac but not Cry1Aa toxins.

    Science.gov (United States)

    Tanaka, Shiho; Miyamoto, Kazuhisa; Noda, Hiroaki; Endo, Haruka; Kikuta, Shingo; Sato, Ryoichi

    2016-04-01

    In a previous report, seven Cry1Ab-resistant strains were identified in the silkworm, Bombyx mori; these strains were shown to have a tyrosine insertion at position 234 in extracellular loop 2 of the ABC transporter C2 (BmABCC2). This insertion was confirmed to destroy the receptor function of BmABCC2 and confer the strains resistance against Cry1Ab and Cry1Ac. However, these strains were susceptible to Cry1Aa. In this report, we examined the mechanisms of the loss of receptor function of the transporter by expressing mutations in Sf9 cells. After replacement of one or two of the five amino acid residues in loop 2 of the susceptible BmABCC2 gene [BmABCC2_S] with alanine, cells still showed susceptibility, retaining the receptor function. Five mutants with single amino acid insertions at position 234 in BmABCC2 were also generated, resulting in loop 2 having six amino acids, which corresponds to replacing the tyrosine insertion in the resistant BmABCC2 gene [BmABCC2_R(+(234)Y)] with another amino acid. All five mutants exhibited loss of function against Cry1Ab and Cry1Ac. These results suggest that the amino acid sequence in loop 2 is less important than the loop size (five vs. six amino acids) or loop structure for Cry1Ab and Cry1Ac activity. Several domain-swapped mutant toxins were then generated among Cry1Aa, Cry1Ab, and Cry1Ac, which are composed of three domains. Swapped mutants containing domain II of Cry1Ab or Cry1Ac did not kill Sf9 cells expressing BmABCC2_R(+(234)Y), suggesting that domain II of the Cry toxin is related to the interaction with the receptor function of BmABCC2. This also suggests that different reactions against Bt-toxins in some B. mori strains, that is, Cry1Ab resistance or Cry1Aa susceptibility, are attributable to structural differences in domain II of Cry1A toxins. PMID:26928903

  19. Susceptibility of field populations of sugarcane borer from non-Bt and Bt maize plants to five individual Cry toxins

    Institute of Scientific and Technical Information of China (English)

    Fangneng Huang; Mukti N.Ghimire; B.Rogers Leonard; Yu-Cheng Zhu; Graham P.Head

    2012-01-01

    Sugarcane borer,Diatraea saccharalis (F.),is a major target of transgenic maize expressing Bacillus thuringiensis (Bt) proteins in South America and the US midsouth region.Resistance development in targct pest populations is a major threat to the sustainable use of Bt crops.In our field trials in 2009,a significant number of live borers and plant injury from D.saccharalis were observed in an experimental SmartStaxTM maize line.The objective of this study was to assess the relative susceptibility of two field populations ofD.saccharalis collected from non-Bt and Bt maize plants containing SmartStaxTM traits to five individual Cry proteins.The five Bt proteins included two proteins (Cry1A.105 and Cry2Ab2) that were expressed in SmartStaxTM maize plants and three other common Bt proteins (Cry1Aa,Cry1Ab and Cry1Ac) that were not produced in SmartStaxTM.Larval mortality and growth inhibition on Bt diet of the fourth gcneration after field collections were evaluated 7 days after release of neonates on the diet surface.The laboratory bioassays showed that 50% lethal concentration (LC50) values for Cry1 A.105 and Cry2Ab2 for the population originated from Bt plants were 3.55-and 1.34-fold greater,respectively,than those of the population collected from non-Bt plants.In contrast,relative to the population from non-Bt plants,the LC50 of the population sampled from Bt plants were 3.85-,2.5-and 1.64-fold more sensitive to Cry1Aa,Cry1Ab and Cry1Ac,respectively.The resuits did not provide clear evidence to conclude that the observed field survival of D.saccharalis on Bt plants was associated with increased levels of resistance.

  20. Construction of occluded recombinant baculoviruses containing the full-length cry1Ab and cry1Ac genes from Bacillus thuringiensis

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    B.M. Ribeiro

    1998-06-01

    Full Text Available The administration of baculoviruses to insects for bioassay purposes is carried out, in most cases, by contamination of food surfaces with a known amount of occlusion bodies (OBs. Since per os infection is the natural route of infection, occluded recombinant viruses containing crystal protein genes (cry1Ab and cry1Ac from Bacillus thuringiensis were constructed for comparison with the baculovirus prototype Autographa californica nucleopolyhedrovirus (AcNPV. The transfer vector pAcUW2B was used for construction of occluded recombinant viruses. The transfer vector containing the crystal protein genes was cotransfected with linearized DNA from a non-occluded recombinant virus. The isolation of recombinant viruses was greatly facilitated by the reduction of background "wild type" virus and the increased proportion of recombinant viruses. Since the recombinant viruses containing full-length and truncated forms of the crystal protein genes did not seem to improve the pathogenicity of the recombinant viruses when compared with the wild type AcNPV, and in order to compare expression levels of the full-length crystal proteins produced by non-occluded and occluded recombinant viruses the full-length cry1Ab and cry1Ac genes were chosen for construction of occluded recombinant viruses. The recombinant viruses containing full-length and truncated forms of the crystal protein genes did not seem to improve its pathogenicity but the size of the larvae infected with the recombinant viruses was significantly smaller than that of larvae infected with the wild type virus.

  1. Evaluation of two cotton varieties CRSP1 and CRSP2 for genetic transformation efficiency, expression of transgenes Cry1Ac + Cry2A, GT gene and insect mortality

    Directory of Open Access Journals (Sweden)

    Arfan Ali

    2016-03-01

    Full Text Available Expression of the transgene with a desirable character in crop plant is the ultimate goal of transgenic research. Transformation of two Bt genes namely Cry1Ac and Cry2A cloned as separate cassette under 35S promoter in pKHG4 plant expression vector was done by using shoot apex cut method of Agrobacterium. Molecular confirmation of putative transgenic cotton plants for Cry1Ac, Cry2A and GT gene was done through PCR and ELISA. Transformation efficiency of CRSP-1 and CRSP-2 was calculated to be 1.2 and 0.8% for Cry1Ac while 0.9 and 0.6% for Cry2A and 1.5 and 0.7% for GTG respectively. CRSP-1 was found to adopt natural environment (acclimatized earlier than CRSP-2 when exposed to sunlight for one month. Expression of Cry1Ac, Cry2A and GTG was found to be 1.2, 1 and 1.3 ng/μl respectively for CRSP-1 as compared to CRSP-2 where expression was recorded to be 0.9, 0.5 and 0.9 ng/μl respectively. FISH analysis of the transgenic CRSP-1 and CRSP-2 demonstrated the presence of one and two copy numbers respectively. Similarly, the response of CRSP-1 against Glyphosate @1900 ml/acre was far better with almost negligible necrotic spot and efficient growth after spray as compared to CRSP-2 where some plants were found to have necrosis and negative control where the complete decay of plant was observed after seven days of spray assay. Similarly, almost 100% mortality of 2nd instar larvae of Heliothis armigera was recorded after three days in CRSP-1 as compared CRSP-2 where insect mortality was found to be less than 90%. Quantitatively speaking non transgenic plants were found with 23–90% leaf damage by insect, while CRSP-1 was with less than 5% and CRSP-2 with 17%. Taken together CRSP1 was found to have better insect control and weedicide resistance along with its natural ability of genetic modification and can be employed by the valuable farmers for better insect control and simultaneously for better production.

  2. Cry1Ac/Sck基因大米的免疫毒理学评价%IMMUNOTOXICOLOGIC ASSESSMENT OF RICE GENETICALLY MODIFIED WITH Cry1ac/Sck GENE

    Institute of Scientific and Technical Information of China (English)

    邢福国; 刘阳; 秦海峰; 崔莉

    2012-01-01

    In order to observe the immunotoxicologic effects of rice genetically modified with Cry1Ac/Sck gene on mice.The Balb/c mice were divided into four groups,transgenic rice group(T group),non-transgenic rice control group(N group),AIN93G control group(C group) and positive control group(C+ group).The mice were fed with corresponding food for 30 days.The immunity indicators of mice were compared.The results showed that the platelet counts of T group were significantly lower than that of N group.But,no significant difference of platelet counts was found between T group and C group.The platelet counts of T,N and C group were all at the normal background level.No significant difference of other observing indexes was found between T group and N group.Most observing indexes of C+ group were significantly lower than that of T,N and C group.The immunotoxicologic effects of rice genetically modified with Cry1Ac/Sck gene on mice were very similar to that of non-transgenic rice,and there was no harmful effect on immune function of mice.All the results suggested that the immunotoxicologic effects of rice genetically modified with Cry1Ac/Sck gene on mice were safe.%为观察转Cry1Ac/Sck基因大米对小鼠免疫功能的影响,将BALB/c小鼠按体重分为4组,即转基因大米组、非转基因大米对照组、AIN93G饲料正常对照组和阳性对照组,相应饲料喂养30d,比较各组小鼠免疫功能改变情况。结果显示,转基因大米组血小板数量显著低于非转基因大米对照组,但是与正常对照组无显著性差异,并且这3组血小板数量均在正常变化范围内;其他观察指标转基因大米组与非转基因大米组相比均无显著性差异;阳性对照组的各项指标,绝大多数均显著低于其他3组。表明转Cry1Ac/Sck基因大米对小鼠免疫功能的影响与非转基因亲本大米基本相同,未对小鼠免疫功能产生不良影响,因此转Cry1Ac/Sck基因大米在小鼠免疫毒理学方面的评价是安全的。

  3. Influence of Dual-Bt Protein Corn on Bollworm, Helicoverpa zea (Boddie), Survivorship on Bollgard II Cotton.

    Science.gov (United States)

    Von Kanel, M B; Gore, J; Catchot, A; Cook, D; Musser, F; Caprio, M

    2016-04-01

    Similar Cry proteins are expressed in both Bt corn, Zea mays L., and cotton, Gossypium hirsutum (L.), commercial production systems. At least one generation of corn earworm, Helicoverpa zea (Boddie), completes development on field corn in the Mid-South before dispersing across the landscape into other crop hosts like cotton. A concern is that Bt corn hybrids may result in selection for H. zea populations with a higher probability of causing damage to Bt cotton. The objective of this study was to determine the susceptibility of H. zea offspring from moths that developed on non-Bt and VT Triple Pro (VT3 PRO) field corn to lyophilized Bollgard II cotton tissue expressing Cry1Ac and Cry2Ab. Offspring of individuals reared on VT3 PRO expressing Cry1A.105 and Cry2Ab had a significantly higher LC50 two out of the three years this study was conducted. Excess larvae were placed on artificial diet and allowed to pupate to determine if there were any inheritable fitness costs associated with parental development on VT3 PRO corn. Offspring resulting from males collected from VT3 PRO had significantly lower pupal weight and longer pupal duration compared with offspring of individuals collected from non-Bt corn. However, offspring from females collected from VT3 PRO were not different from non-Bt offspring. Paternal influence on offspring in insects is not commonly observed, but illustrates the side effects of development on a transgenic plant expressing less than a high dose, 25 times the concentration needed to kill susceptible larvae.

  4. Qualitative and event-specific real-time PCR detection methods for Bt brinjal event EE-1.

    Science.gov (United States)

    Randhawa, Gurinder Jit; Sharma, Ruchi; Singh, Monika

    2012-01-01

    Bt brinjal event EE-1 with cry1Ac gene, expressing insecticidal protein against fruit and shoot borer, is the first genetically modified food crop in the pipeline for commercialization in India. Qualitative polymerase chain reaction (PCR) along with event-specific conventional as well as real-time PCR methods to characterize the event EE-1 is reported. A multiplex (pentaplex) PCR system simultaneously amplifying cry1Ac transgene, Cauliflower Mosaic Virus (CaMV) 35S promoter, nopaline synthase (nos) terminator, aminoglycoside adenyltransferase (aadA) marker gene, and a taxon-specific beta-fructosidase gene in event EE-1 has been developed. Furthermore, construct-specific PCR, targeting the approximate 1.8 kb region of inserted gene construct comprising the region of CaMV 35S promoter and cry1Ac gene has also been developed. The LOD of developed EE-1 specific conventional PCR assay is 0.01%. The method performance of the reported real-time PCR assay was consistent with the acceptance criteria of Codex Alimentarius Commission ALINORM 10/33/23, with the LOD and LOQ values of 0.05%. The developed detection methods would not only facilitate effective regulatory compliance for identification of genetic traits, risk assessment, management, and postrelease monitoring, but also address consumer concerns and resolution of legal disputes.

  5. Qualitative and event-specific real-time PCR detection methods for Bt brinjal event EE-1.

    Science.gov (United States)

    Randhawa, Gurinder Jit; Sharma, Ruchi; Singh, Monika

    2012-01-01

    Bt brinjal event EE-1 with cry1Ac gene, expressing insecticidal protein against fruit and shoot borer, is the first genetically modified food crop in the pipeline for commercialization in India. Qualitative polymerase chain reaction (PCR) along with event-specific conventional as well as real-time PCR methods to characterize the event EE-1 is reported. A multiplex (pentaplex) PCR system simultaneously amplifying cry1Ac transgene, Cauliflower Mosaic Virus (CaMV) 35S promoter, nopaline synthase (nos) terminator, aminoglycoside adenyltransferase (aadA) marker gene, and a taxon-specific beta-fructosidase gene in event EE-1 has been developed. Furthermore, construct-specific PCR, targeting the approximate 1.8 kb region of inserted gene construct comprising the region of CaMV 35S promoter and cry1Ac gene has also been developed. The LOD of developed EE-1 specific conventional PCR assay is 0.01%. The method performance of the reported real-time PCR assay was consistent with the acceptance criteria of Codex Alimentarius Commission ALINORM 10/33/23, with the LOD and LOQ values of 0.05%. The developed detection methods would not only facilitate effective regulatory compliance for identification of genetic traits, risk assessment, management, and postrelease monitoring, but also address consumer concerns and resolution of legal disputes. PMID:23451391

  6. Chloroplast-targeted expression of recombinant crystal-protein gene in cotton: an unconventional combat with resistant pests.

    Science.gov (United States)

    Kiani, Sarfraz; Mohamed, Bahaeldeen Babiker; Shehzad, Kamran; Jamal, Adil; Shahid, Muhammad Naveed; Shahid, Ahmad Ali; Husnain, Tayyab

    2013-07-10

    Plants transformed with single Bt gene are liable to develop insect resistance and this has already been reported in a number of studies carried out around the world where Bt cotton was cultivated on commercial scale. Later, it was envisaged to transform plants with more than one Bt genes in order to combat with resistant larvae. This approach seems valid as various Bt genes possess different binding domains which could delay the likely hazards of insect resistance against a particular Bt toxin. But it is difficult under field conditions to develop homozygous plants expressing all Bt genes equally after many generations without undergoing recombination effects. A number of researches claiming to transform plants from three to seven transgenes in a single plant were reported during the last decade but none has yet applied for patent of homozygous transgenic lines. A better strategy might be to use hybrid-Bt gene(s) modified for improved lectin-binding domains to boost Bt receptor sites in insect midgut. These recombinant-Bt gene(s) would express different lectin domains in a single polypeptide and it is relatively easy to develop homozygous transgenic lines under field conditions. Enhanced chloroplast-localized expression of hybrid-Bt gene would leave no room for insects to develop resistance. We devised and successfully applied this strategy in cotton (Gossypium hirsutum) and data up to T3 generation showed that our transgenic cotton plants were displaying enhanced chloroplast-targeted Cry1Ac-RB expression. Laboratory and field bioassays gave promising results against American bollworm (Heliothis armigera), pink bollworm (Pictinophora scutigera) and fall armyworm (Spodoptera frugiperda) that otherwise, were reported to have evolved resistance against Cry1Ac toxin. Elevated levels of hybrid-Bt toxin were confirmed by ELISA of chloroplast-enriched protein samples extracted from leaves of transgenic cotton lines. While, localization of recombinant Cry1Ac-RB protein in

  7. Effects of feeding transgenic corn with mCry1Ac or maroACC gene to laying hens for 12 weeks on growth, egg quality and organ health.

    Science.gov (United States)

    Zhong, R Q; Chen, L; Gao, L X; Zhang, L L; Yao, B; Yang, X G; Zhang, H F

    2016-08-01

    The objective of the present study was to investigate the effect of feeding two transgenic corn lines containing the mCry1Ac gene from Bacillus thuringiensis strain (BT-799) and the maroACC gene from Agrobacterium tumefaciens strain (CC-2), respectively, on growth, egg quality and organ health indicators. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Healthy hens (n=96 placed in cages; 3 hens/cage) were randomly assigned to one of four corn-soybean meal dietary treatments (8 cages/treatment) formulated with the following corn: non-transgenic near-isoline control corn (control), BT-799 corn, CC-2 corn and commercially available non-transgenic reference corn (reference). The experiment was divided into three 4-week phases (week 1 to 4, week 5 to 8 and week 9 to 12), during which hens were fed mash diets. Performance (BW, feed intake and egg production) and egg quality were determined. Following slaughter at the end of 12 weeks of feeding (n=8/treatment), carcass yield and organ weights (heart, liver, spleen, lung, kidneys, stomach and ovary) were recorded; organs and intestines were sampled for histological analysis. Analysis of serum biochemistry parameters to assess the liver and kidney function were performed. No differences in BW, egg production and production efficiency were observed between hens consuming the control diet and hens consuming the BT-799 or CC-2 diet. Haugh unit measures and egg component weights were similar between the control and test groups. Carcass yield was not affected by the diet treatment. Similar organosomatic indices and serum parameters did not indicate the characteristics of organ dysfunction. All observed values of the BT-799 and CC-2 groups were within the calculated tolerance intervals. This research indicates that the performance, egg quality, organ health and carcass yield of laying hens fed diets containing the BT-799 or CC-2 corn line were similar

  8. New insight to structure-function relationship of GalNAc mediated primary interaction between insecticidal Cry1Ac toxin and HaALP receptor of Helicoverpa armigera.

    Science.gov (United States)

    Sengupta, Anindita; Sarkar, Anindya; Priya, Prerna; Ghosh Dastidar, Shubhra; Das, Sampa

    2013-01-01

    Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns.

  9. Effects of 90-Day Feeding of Transgenic Maize BT799 on the Reproductive System in Male Wistar Rats

    Directory of Open Access Journals (Sweden)

    Qian-ying Guo

    2015-12-01

    Full Text Available BT799 is a genetically modified (GM maize plant that expresses the Cry1Ac gene from Bacillus thuringiensis (Bt. The Cry1Ac gene was introduced into maize line Zhen58 to encode the Bt crystal protein and thus produce insect-resistant maize BT799. Expression of Bt protein in planta confers resistance to Lepidopteran pests and corn rootworms. The present study was designed to investigate any potential effects of BT799 on the reproductive system of male rats and evaluate the nutritional value of diets containing BT799 maize grain in a 90-day subchronic rodent feeding study. Male Wistar rats were fed with diets containing BT799 maize flours or made from its near isogenic control (Zhen58 at a concentration of 84.7%, nutritionally equal to the standard AIN-93G diet. Another blank control group of male rats were treated with commercial AIN-93G diet. No significant differences in body weight, hematology and serum chemistry results were observed between rats fed with the diets containing transgenic BT799, Zhen58 and the control in this 13-week feeding study. Results of serum hormone levels, sperm parameters and relative organ/body weights indicated no treatment-related side effects on the reproductive system of male rats. In addition, no diet-related changes were found in necropsy and histopathology examinations. Based on results of the current study, we did not find any differences in the parameters tested in our study of the reproductive system of male rats between BT799 and Zhen58 or the control.

  10. Effects of 90-Day Feeding of Transgenic Maize BT799 on the Reproductive System in Male Wistar Rats.

    Science.gov (United States)

    Guo, Qian-ying; He, Li-xia; Zhu, Han; Shang, Jun-li; Zhu, Ling-yan; Wang, Jun-bo; Li, Yong

    2015-12-01

    BT799 is a genetically modified (GM) maize plant that expresses the Cry1Ac gene from Bacillus thuringiensis (Bt). The Cry1Ac gene was introduced into maize line Zhen58 to encode the Bt crystal protein and thus produce insect-resistant maize BT799. Expression of Bt protein in planta confers resistance to Lepidopteran pests and corn rootworms. The present study was designed to investigate any potential effects of BT799 on the reproductive system of male rats and evaluate the nutritional value of diets containing BT799 maize grain in a 90-day subchronic rodent feeding study. Male Wistar rats were fed with diets containing BT799 maize flours or made from its near isogenic control (Zhen58) at a concentration of 84.7%, nutritionally equal to the standard AIN-93G diet. Another blank control group of male rats were treated with commercial AIN-93G diet. No significant differences in body weight, hematology and serum chemistry results were observed between rats fed with the diets containing transgenic BT799, Zhen58 and the control in this 13-week feeding study. Results of serum hormone levels, sperm parameters and relative organ/body weights indicated no treatment-related side effects on the reproductive system of male rats. In addition, no diet-related changes were found in necropsy and histopathology examinations. Based on results of the current study, we did not find any differences in the parameters tested in our study of the reproductive system of male rats between BT799 and Zhen58 or the control. PMID:26633453

  11. Degradation and detection of transgenic Bacillus thuringiensis DNA and proteins in flour of three genetically modified rice events submitted to a set of thermal processes.

    Science.gov (United States)

    Wang, Xiaofu; Chen, Xiaoyun; Xu, Junfeng; Dai, Chen; Shen, Wenbiao

    2015-10-01

    This study aimed to investigate the degradation of three transgenic Bacillus thuringiensis (Bt) genes (Cry1Ab, Cry1Ac, and Cry1Ab/Ac) and the corresponding encoded Bt proteins in KMD1, KF6, and TT51-1 rice powder, respectively, following autoclaving, cooking, baking, or microwaving. Exogenous Bt genes were more stable than the endogenous sucrose phosphate synthase (SPS) gene, and short DNA fragments were detected more frequently than long DNA fragments in both the Bt and SPS genes. Autoclaving, cooking (boiling in water, 30 min), and baking (200 °C, 30 min) induced the most severe Bt protein degradation effects, and Cry1Ab protein was more stable than Cry1Ac and Cry1Ab/Ac protein, which was further confirmed by baking samples at 180 °C for different periods of time. Microwaving induced mild degradation of the Bt and SPS genes, and Bt proteins, whereas baking (180 °C, 15 min), cooking and autoclaving led to further degradation, and baking (200 °C, 30 min) induced the most severe degradation. The findings of the study indicated that degradation of the Bt genes and proteins somewhat correlated with the treatment intensity. Polymerase chain reaction, enzyme-linked immunosorbent assay, and lateral flow tests were used to detect the corresponding transgenic components. Strategies for detecting transgenic ingredients in highly processed foods are discussed.

  12. Degradation and detection of transgenic Bacillus thuringiensis DNA and proteins in flour of three genetically modified rice events submitted to a set of thermal processes.

    Science.gov (United States)

    Wang, Xiaofu; Chen, Xiaoyun; Xu, Junfeng; Dai, Chen; Shen, Wenbiao

    2015-10-01

    This study aimed to investigate the degradation of three transgenic Bacillus thuringiensis (Bt) genes (Cry1Ab, Cry1Ac, and Cry1Ab/Ac) and the corresponding encoded Bt proteins in KMD1, KF6, and TT51-1 rice powder, respectively, following autoclaving, cooking, baking, or microwaving. Exogenous Bt genes were more stable than the endogenous sucrose phosphate synthase (SPS) gene, and short DNA fragments were detected more frequently than long DNA fragments in both the Bt and SPS genes. Autoclaving, cooking (boiling in water, 30 min), and baking (200 °C, 30 min) induced the most severe Bt protein degradation effects, and Cry1Ab protein was more stable than Cry1Ac and Cry1Ab/Ac protein, which was further confirmed by baking samples at 180 °C for different periods of time. Microwaving induced mild degradation of the Bt and SPS genes, and Bt proteins, whereas baking (180 °C, 15 min), cooking and autoclaving led to further degradation, and baking (200 °C, 30 min) induced the most severe degradation. The findings of the study indicated that degradation of the Bt genes and proteins somewhat correlated with the treatment intensity. Polymerase chain reaction, enzyme-linked immunosorbent assay, and lateral flow tests were used to detect the corresponding transgenic components. Strategies for detecting transgenic ingredients in highly processed foods are discussed. PMID:26277627

  13. Monarch larvae sensitivity to Bacillus thuringiensis- purified proteins and pollen.

    Science.gov (United States)

    Hellmich, R L; Siegfried, B D; Sears, M K; Stanley-Horn, D E; Daniels, M J; Mattila, H R; Spencer, T; Bidne, K G; Lewis, L C

    2001-10-01

    Laboratory tests were conducted to establish the relative toxicity of Bacillus thuringiensis (Bt) toxins and pollen from Bt corn to monarch larvae. Toxins tested included Cry1Ab, Cry1Ac, Cry9C, and Cry1F. Three methods were used: (i) purified toxins incorporated into artificial diet, (ii) pollen collected from Bt corn hybrids applied directly to milkweed leaf discs, and (iii) Bt pollen contaminated with corn tassel material applied directly to milkweed leaf discs. Bioassays of purified Bt toxins indicate that Cry9C and Cry1F proteins are relatively nontoxic to monarch first instars, whereas first instars are sensitive to Cry1Ab and Cry1Ac proteins. Older instars were 12 to 23 times less susceptible to Cry1Ab toxin compared with first instars. Pollen bioassays suggest that pollen contaminants, an artifact of pollen processing, can dramatically influence larval survival and weight gains and produce spurious results. The only transgenic corn pollen that consistently affected monarch larvae was from Cry1Ab event 176 hybrids, currently corn planted and for which re-registration has not been applied. Results from the other types of Bt corn suggest that pollen from the Cry1Ab (events Bt11 and Mon810) and Cry1F, and experimental Cry9C hybrids, will have no acute effects on monarch butterfly larvae in field settings. PMID:11559841

  14. New insight to structure-function relationship of GalNAc mediated primary interaction between insecticidal Cry1Ac toxin and HaALP receptor of Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Anindita Sengupta

    Full Text Available Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns.

  15. Protection against Naegleria fowleri infection in mice immunized with Cry1Ac plus amoebic lysates is dependent on the STAT6 Th2 response.

    Science.gov (United States)

    Carrasco-Yepez, M; Rojas-Hernandez, S; Rodriguez-Monroy, M A; Terrazas, L I; Moreno-Fierros, L

    2010-01-01

    We previously reported that intranasal administration of Cry1Ac protoxin alone or in combination with amoebic lysates increases protection against Naegleria fowleri meningoencephalitis in mice. Those results suggested that both antibody responses and innate immune mechanisms may be participating in the protective effects observed. The present study was aimed to investigate whether the STAT6-induced Th2 immune response is essential for the resistance to N. fowleri infection, conferred by immunization with amoebic lysates plus Cry1Ac. STAT6-deficient (STAT6-/-) and wild-type (STAT6+/+) BALB/c mice were immunized by the intranasal route with a combination of N. fowleri lysates plus Cry1Ac, and subsequently challenged with lethal doses of N. fowleri trophozoites. STAT6+/+ mice displayed 100% protection, while no protection was observed in STAT6-/- mice. Significantly higher titres of Th2-associated IgG1 as well as interleukin-4 (IL-4) were found in STAT6+/+ mice, whereas in STAT6-/- mice significantly more IL-12 and IFN-gamma as well as significantly higher titres of Th1-associated IgG2a were detected. Thus, whereas protected STAT6+/+-immunized mice elicited a Th-2 type inclined immune response that produced predominantly humoral immunity, unprotected STAT6-/- mice exhibited a polarized Th1 type cellular response. These findings suggest that the STAT6-signalling pathway is critical for defence against N. fowleri infection.

  16. Agronomic performance, chromosomal stability and resistance to velvetbean caterpillar of transgenic soybean expressing cry1Ac gene Performance agronômica, estabilidade cromossômica e resistência à lagarta-da-soja em soja transgênica que expressa o gene cry1Ac

    Directory of Open Access Journals (Sweden)

    Milena Schenkel Homrich

    2008-07-01

    Full Text Available The objective of this work was to analyze the agronomic performance and chromosomal stability of transgenic homozygous progenies of soybean [Glycine max (L. Merrill.], and to confirm the resistance of these plants against Anticarsia gemmatalis. Eleven progenies expressing cry1Ac, hpt and gusA genes were evaluated for agronomic characteristics in relation to the nontransformed parent IAS 5 cultivar. Cytogenetical analysis was carried out on transgenic and nontransgenic plants. Two out of the 11 transgenic progenies were also evaluated, in vitro and in vivo, for resistance to A. gemmatalis. Two negative controls were used in resistance bioassays: a transgenic homozygous line, containing only the gusA reporter gene, and nontransgenic 'IAS 5' plants. The presence of cry1Ac transgene affected neither the development nor the yield of plants. Cytogenetical analysis showed that transgenic plants presented normal karyotype. In detached-leaf bioassay, cry1Ac plants exhibited complete efficacy against A. gemmatalis, whereas negative controls were significantly damaged. Whole-plant feeding assay confirmed a very high protection of cry1Ac against velvetbean caterpillar, while nontransgenic 'IAS 5' plants and homozygous gusA line exhibited 56.5 and 71.5% defoliation, respectively. The presence of cry1Ac transgene doesn't affect the majority of agronomic traits (including yield of soybean and grants high protection against A. gemmatalis.O objetivo deste trabalho foi analisar a performance agronômica e a estabilidade cromossômica de progênies transgênicas homozigotas de soja [Glycine max (L. Merrill.], e confirmar a resistência dessas plantas a Anticarsia gemmatalis. Onze progênies com expressão dos genes cry1Ac, hpt e gusA foram avaliadas quanto às características agronômicas, em relação à cultivar parental IAS 5 não transformada. Análises citogenéticas foram realizadas em plantas transgênicas e não transgênicas. Duas das 11 prog

  17. Introgression of Bt Genes in Novel Germplasm and Contribution to Indian Cotton Economy

    Institute of Scientific and Technical Information of China (English)

    VIDYASAGAR; Parchuri

    2008-01-01

    Emergence of transgenic Bt-cotton technology has opened up a new chapter in Indian cotton production in 21st century.The cry1Ac gene of Monsanto derived from American Upland Coker-312 background was not directly suitable for varied cotton growing situations in India.Delivery of Bt-gene

  18. Comparison of susceptibility of Chilo suppressalis and Bombyx mori to five Bacillus thuringiensis proteins.

    Science.gov (United States)

    Jiao, Yaoyu; Yang, Yan; Meissle, Michael; Peng, Yufa; Li, Yunhe

    2016-05-01

    Transformation of rice with genes encoding insecticidal Cry proteins from Bacillus thuringiensis (Bt) should confer high resistance to target lepidopteran pests, such as Chilo suppressalis, and low toxicity to non-target organisms, such as silkworm Bombyx mori. Five purified Cry proteins that have been used for plant transformation were tested using dietary exposure assays. The susceptibility of C. suppressalis larvae to the five insecticidal proteins in the decreasing order was: Cry1Ca>Cry1Ab>Cry1Ac>Cry2Aa>Cry1Fa. However, the toxicities of the Cry proteins to B. mori were in the order: Cry1Fa>Cry1Ca>Cry2Aa>Cry1Ab>Cry1Ac. The Cry1Ca, Cry1Ab and Cry1Ac proteins exhibited relatively high toxicity to C. suppressalis larvae, with EC50 values of 16.4, 45.8 and 89.6ng/g, respectively. The toxicities of the three Cry proteins to B. mori larvae were 8, 14, and 22times lower, with EC50 values of 138.3, 628.4 and 1939.2ng/g, respectively. The Cry1Fa and Cry2Aa proteins showed high toxicity to B. mori larvae, with EC50 values of 135.7 and 373.9ng/g, respectively, but low toxicity to C. suppressalis larvae, with EC50 values of 6092.1 and 1208.5ng/g, respectively. We thus conclude that Cry1Ab, Cry1Ac and Cry1Ca are appropriate for transforming rice to control lepidopteran rice pests. In contrast, Cry1Fa and Cry2Aa are not appropriate due to their high toxicity to silkworm larvae and low activity against the target pest.

  19. Early warning of cotton bollworm resistance associated with intensive planting of Bt cotton in China.

    Directory of Open Access Journals (Sweden)

    Haonan Zhang

    Full Text Available Transgenic crops producing Bacillus thuringiensis (Bt toxins kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to promote survival of susceptible pests. To delay pest resistance to transgenic cotton producing Bt toxin Cry1Ac, farmers in the United States and Australia planted refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. Here we report data from a 2010 survey showing field-evolved resistance to Cry1Ac of the major target pest, cotton bollworm (Helicoverpa armigera, in northern China. Laboratory bioassay results show that susceptibility to Cry1Ac was significantly lower in 13 field populations from northern China, where Bt cotton has been planted intensively, than in two populations from sites in northwestern China where exposure to Bt cotton has been limited. Susceptibility to Bt toxin Cry2Ab did not differ between northern and northwestern China, demonstrating that resistance to Cry1Ac did not cause cross-resistance to Cry2Ab, and implying that resistance to Cry1Ac in northern China is a specific adaptation caused by exposure to this toxin in Bt cotton. Despite the resistance detected in laboratory bioassays, control failures of Bt cotton have not been reported in China. This early warning may spur proactive countermeasures, including a switch to transgenic cotton producing two or more toxins distinct from Cry1A toxins.

  20. Sustained susceptibility of pink bollworm to Bt cotton in the United States.

    Science.gov (United States)

    Tabashnik, Bruce E; Morin, Shai; Unnithan, Gopalan C; Yelich, Alex J; Ellers-Kirk, Christa; Harpold, Virginia S; Sisterson, Mark S; Ellsworth, Peter C; Dennehy, Timothy J; Antilla, Larry; Liesner, Leighton; Whitlow, Mike; Staten, Robert T; Fabrick, Jeffrey A; Li, Xianchun; Carrière, Yves

    2012-01-01

    Evolution of resistance by pests can reduce the benefits of transgenic crops that produce toxins from Bacillus thuringiensis (Bt) for insect control. One of the world's most important cotton pests, pink bollworm (Pectinophora gossypiella), has been targeted for control by transgenic cotton producing Bt toxin Cry1Ac in several countries for more than a decade. In China, the frequency of resistance to Cry1Ac has increased, but control failures have not been reported. In western India, pink bollworm resistance to Cry1Ac has caused widespread control failures of Bt cotton. By contrast, in the state of Arizona in the southwestern United States, monitoring data from bioassays and DNA screening demonstrate sustained susceptibility to Cry1Ac for 16 y. From 1996-2005, the main factors that delayed resistance in Arizona appear to be abundant refuges of non-Bt cotton, recessive inheritance of resistance, fitness costs associated with resistance and incomplete resistance. From 2006-2011, refuge abundance was greatly reduced in Arizona, while mass releases of sterile pink bollworm moths were made to delay resistance as part of a multi-tactic eradication program. Sustained susceptibility of pink bollworm to Bt cotton in Arizona has provided a cornerstone for the pink bollworm eradication program and for integrated pest management in cotton. Reduced insecticide use against pink bollworm and other cotton pests has yielded economic benefits for growers, as well as broad environmental and health benefits. We encourage increased efforts to combine Bt crops with other tactics in integrated pest management programs.

  1. Effects of transgenic Cry1A+CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae (Hymenoptera:Ichneumonidae)

    Institute of Scientific and Technical Information of China (English)

    XIAO-XIALIU; CHANG-GUISUN; QING-WENZHANG

    2005-01-01

    The effect oftransgenic double genes, Cry1A + CpTlcotton and Cry1Ac toxin on the parasitoid, Carnpoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Hübner), was investigated in the laboratory. Helicoverpa armigera larvae when in the first,second and third instar could not survive if fed on transgenic cotton leaves. Consequently,C. chlorideae larvae could not complete their development if parasitizing on such hosts.After H. armigera larvae were reared on transgenic or traditional cotton leaves for 12-48 hours, they were parasitized by C. chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for 12-48 h. The present results showed that the body weight of larvae of the parasitoids were significantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fed on traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal and adult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaves longer than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgenic cotton leaves in each treatment was not significantly different from those of controls. The longevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was not significantly different with that of the control.

  2. Cry1Fa对Cry1Ac抗性棉铃虫的毒力评价%Evaluation of the toxicity of Cry1Fa to the Cry1Ac-resistant cotton bollworm,Helicoverpa armigera(Lepidoptera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    魏纪珍; 郭予元; 高希武; 张涛; 梁革梅

    2012-01-01

    为了防治多种鳞翅日害虫,表达Cry1 Fa的转基因玉米和棉花已在美国商业化种植.明确棉铃虫Helicoverpa armigera对Cry1Fa与Cry1 Ac的交互抗性及这两种杀虫蛋白之间的协同作用,可以为表达Cry1 Fa+Cry1 Ac的转双价抗虫棉花的合理应用提供依据.本实验测定了Cry1 Fa对棉铃虫敏感品系(96S)及用Cry1Ac筛选的抗性品系(BtR,抗性倍数2194.15倍)的毒力,发现Cry1 Fa对敏感棉铃虫的毒力远低于Cry1 Ac,LC50值是Cry1 Ac的504.80倍;而且抗性品系BtR对Cry1Fa存在19.98倍的交互抗性.Cry1 Fa与Cry1 Ac混用可以提高Cry1 Fa毒杀敏感棉铃虫的效果,尤其是Cry1 Fa浓度较低时,加入Cry1Ac,可以显著增加Cry1 Fa的毒力;但只有加入较高浓度的Cry1 Fa时才能增加Cry1 Ac的毒力.由于BtR品系已经对Cry1 Ac产生抗性,Cry1Ac对抗性棉铃虫的毒力明最降低;在较高浓度的Cry1Ac中加入Cry1 Fa可以显著增加棉铃虫的死亡率(P=0.0015,F=6.88,df=6),但最高死亡率仅为58.33%.D-饱和最优试验的结果证实,Cry1 Ac对于敏感棉铃虫的死亡率的影响达到显著水平(t1=13.76>t0.os),Cry1Ac 与 Cry1Fa的交互作用对毒力的影响也达到显著水平(t22=2.42>t0.05;t11=6.95>t0.05;t12=3.43>t0.05).Cry1Ac和Cry1Fa对抗性棉铃虫死亡率的影响都达到显著水平(t1=3.03>t0.05;t2=2.59>t0.05),但Cry1 Ac是决定抗、感棉铃虫死亡率的关键因素;Cry1Ac与Cry1 Fa最佳浓度配比范围都是1.41~2.10 μg/cm2;在抗性品系中,Cry1 Ac和Cry1 Fa的交互作用不显著.所以,尽管Cry1F+Cry1A作物扩大了杀虫谱,但棉铃虫对这两种蛋白存在交互抗性,而且这两种蛋白混用对治理抗Cry1 Ac棉铃虫的效果不理想,因此不建议在中国种植表达Cry1F+Cry1A的棉花.%Cry 1 Fa-expressing corn and cotton have been commercially planted in U. S in order to effectively control several Lepidoptera pests. Making clear the cross-resistance of cotton bollworms (Helicoverpa armigera

  3. Expresión de la proteína Cry1Ac en tejidos de líneas transgénicas de papa (Solanum tuberosum spp. Andígena Var. Diacol capiro.

    Directory of Open Access Journals (Sweden)

    Blanco Martinez Jennifer Teresa

    2010-08-01

    ="ES-TRAD">y no mostraron diferencias significativas entre las líneas analizadas, ni entre las tres etapas del desarrollo. No se evidenciaron diferencias significativas entre las líneas transgénicas con respecto al control al hacer un análisis de algunas características fenotípicas relevantes. Los resultados encontrados sugieren la realización de seguimientos y ensayos de bioseguridad sobre este material, ya que los altos niveles de expresión en todos los tejidos analizados, pueden afectar a organismos no blanco.

     

    ABSTRACT

    Potato is the fourth of the most important crop and foodstuff in the world, in Colombia around 2.8 millions of tons are produced annually supporting economically 90000 families. In the country, the major economic impact in the crop is caused by Tecia solanivora that originates loses up to 100% in the tuber production. The genetic plant breeding related to the introduction of Cry genes which codify insecticidal crystal proteins is an alternative for reducing the insect attack in commercial crops. In this work, the insertion, transcription and expression of Cry1Ac gen was characterized in different tissues and three development stages of two

  4. FROM Qutn TO Bt COTTON: DEVELOPMENT, ADOPTION AND PROSPECTS. A REVIEW.

    Science.gov (United States)

    Maik, W; Abid, M A; Cheema, H M N; Khan, A A; Iqbal, M Z; Qayyum, A; Hanif, M; Bibi, N; Yuan, S N; Yasmeen, A; Mahmood, A; Ashraf, J

    2015-01-01

    Cotton has unique history of domestication, diversification, and utilization. Globally it is an important cash crop that provides raw material for textile industry. The story of cotton started from human civilization and the climax arrived with the efforts of developing transgenic cotton for various traits. Though conventional breeding brought steady improvement in developing resistance against biotic stresses but recent success story of gene transferfrom Bacillus thuringiensis into cotton showed game changing effects on cotton cultivation. Amongst various families of insecticidal proteins Bt Cry-toxins received more attention because of specificity against receptors on the cell membranes of insect midgut epithelial cells. Rapid Bt cotton adoption by farmers due to its economic and environmental benefits has changed the landscape of cotton cultivation in many countries. But the variable expression of Bt transgene in the newly developed Bt cotton genotypes in tropical environment is questionable. Variability of toxin level in different plant parts at various life stage of plant is an outcome of genotypic interaction with environmental factors. Temporal gene expression of Cry1Ac is also blamed for the epigenetic background in which transgene has been inserted. The presence of genotypes with sub-lethal level of Bt toxin might create resistance in Lepidopteron insects, limiting the use of Bt cotton in future, with the opportunityfor other resistance development strategies to get more attention like gene stacking. Until the farmers get access to more recent technology, best option is to delay the development of resistance by applying Insect Resistance Management (IRM) strategies. PMID:26841496

  5. A comparison of spider communities in Bt and non-Bt rice fields.

    Science.gov (United States)

    Lee, Sue Yeon; Kim, Seung Tae; Jung, Jong Kook; Lee, Joon-Ho

    2014-06-01

    To assess the potential adverse effects of a Bt rice line (Japonica rice cultivar, Nakdong) expressing a synthetic cry1Ac1 gene, C7-1-9-1-B, which was highly active against all larval stages of Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Crambidae), we investigated the community structure of spiders in Bt and non-Bt rice fields during the rice-growing season in 2007 and 2008 in Chungcheongnam-do, Korea. Spiders were surveyed with a sweep net and suction device. Suction sampling captured more spiders, measured in terms of species level and abundance, than sweeping. Araneidae and Thomisidae were captured more by sweeping, and certain species were captured only by sweeping. These findings show that both suction and sweep sampling methods should be used because these methods are most likely complementary. In total, 29 species in 23 genera and nine families were identified from the 4,937 spiders collected, and both Bt and non-Bt rice fields showed a typical Korean spider assemblage. The temporal patterns of spider species richness and spider abundance were very similar between Bt and non-Bt rice, although significant differences in species richness were observed on a few occasions. Overall, spider community structure, including diversity, the dominant species, and abundance did not differ between Bt and non-Bt rice. The results of the study indicated that the transgenic Cry1Ac rice lines tested in this study had no adverse effects on the spider community structure of the rice fields.

  6. BT799玉米对亚洲玉米螟抗性研究%Resistance of transgenic Bt corn variety BT799 to the Asian corn borer

    Institute of Scientific and Technical Information of China (English)

    王月琴; 何康来; 江帆; 王依冬; 张天涛; 王振营; 白树雄

    2014-01-01

    Objectives] To review the resistance of transgenic Bt corn to target pests which is one of the primarily steps for research and development of insect-resistant, transgenic corn. This review mainly evaluates the resistance of transgenic Cry1Ac gene corn variety BT799 to the Asian corn borer (ACB), Ostrinia furnacalis (Guenée), and measured the quantity of Cry1Ac protein expressed in corn plant tissues. [Methods] Enzyme-linked immunosorbent assays, laboratory bioassay and field studies with artificial infestation were employed in this study. [Results] The expression levels of Cry1Ac protein were 768.0 ng/g (protein/fresh leaves), 1452.8-2978.5 ng/g (protein/dry mass of silk, husk and young kernels). Leaf-feeding rates in field trials indicated that BT799 and CC-2XBT799 were highly resistant to ACB. The survival of ACB larvae feeding on Zhengdan 958K, a single cross hybrid containing BT799, was significantly lower (0-37.5%) than that of larvae that fed on non-Bt Zhengdan 958 (89.9%-100.0%). In addition, larval survival of Cry1Ac-, Cry1Ie-, and Cry1F-selected ACB strains (ACB-AcR, ACB-IeR and ACB-FR) were significantly different when fed on Zhengdan 958K. ACB-IeR had the lowest survival followed by ACB-FR, both of them had significantly lower survival than those that fed on the control Zhengdan 958. However, the survival of ACB-AcR was not significantly different from larvae feeding on the control Zhengdan 958. [Conclusion] These results suggests that the transgenic Bt corn variety BT799 is highly toxic to the ACB and can provide effective control for ACB in the field.%【目的】抗螟性鉴定是转基因抗虫玉米研发的重要一环。本文主要就转基因玉米BT799对亚洲玉米螟的抗性展开评价,同时测定了BT799植株组织中Cry1Ac蛋白的表达量。【方法】采用了酶联免疫吸附测定法(ELISA)、室内生测和田间人工接虫鉴定3种方法。【结果】转基因抗虫玉米BT799组织中Cry1Ac蛋白含量分别为768

  7. Large-scale test of the natural refuge strategy for delaying insect resistance to transgenic Bt crops.

    Science.gov (United States)

    Jin, Lin; Zhang, Haonan; Lu, Yanhui; Yang, Yihua; Wu, Kongming; Tabashnik, Bruce E; Wu, Yidong

    2015-02-01

    The 'natural refuge strategy" for delaying insect resistance to transgenic cotton that produces insecticidal proteins from Bacillus thuringiensis (Bt) relies on refuges of host plants other than cotton that do not make Bt toxins. We tested this widely adopted strategy by comparing predictions from modeling with data from a four-year field study of cotton bollworm (Helicoverpa armigera) resistance to transgenic cotton producing Bt toxin Cry1Ac in six provinces of northern China. Bioassay data revealed that the percentage of resistant insects increased from 0.93% in 2010 to 5.5% in 2013. Modeling predicted that the percentage of resistant insects would exceed 98% in 2013 without natural refuges, but would increase to only 1.1% if natural refuges were as effective as non-Bt cotton refuges. Therefore, the results imply that natural refuges delayed resistance, but were not as effective as an equivalent area of non-Bt cotton refuges. The percentage of resistant insects with nonrecessive inheritance of resistance increased from 37% in 2010 to 84% in 2013. Switching to Bt cotton producing two or more toxins and integrating other control tactics could slow further increases in resistance.

  8. Development and reproduction of Spodoptera eridania (Lepidoptera: Noctuidae) and its egg parasitoid Telenomus remus (Hymenoptera: Platygastridae) on the genetically modified soybean (Bt) MON 87701×MON 89788.

    Science.gov (United States)

    Bortolotto, O C; Silva, G V; de Freitas Bueno, A; Pomari, A F; Martinelli, S; Head, G P; Carvalho, R A; Barbosa, G C

    2014-12-01

    Genetically modified crops with insect resistance genes from Bacillus thuringiensis Berliner (Bt-plants) are increasingly being cultivated worldwide. Therefore, it is critical to improve our knowledge of their direct or indirect impact not only on target pests but also on non-target arthropods. Hence, this study evaluates comparative leaf consumption and performance of Spodoptera eridania (Cramer), a species that is tolerant of the Cry1Ac protein, fed with Bt soybean, MON 87701×MON 89788 or its near [corrected] non-Bt isoline. Using this species as a model, we assessed [corrected] the comparative performance of the egg parasitoid Telenomus remus Nixon on eggs of S. eridania produced from individuals that fed on these two soybean genotypes [corrected] as larvae. Results showed that Bt soybean did not affect pest foliage consumption, but did reduce larvel duration by two days despite larvae in both treatments having six instars. Nevertheless, survival of S. eridania larvae, pupal weight, sex ratio, fecundity and longevity of female moths, and egg viability did not differ between Bt and non-Bt soybeans. Adult longevity of S. eridania males was increased when caterpillars were fed with Bt soybean versus the near isoline. No adverse effects of this technology were observed for the egg parasitoid T. remus. [corrected]. PMID:25248849

  9. Effects of Rice Genetically Modified With Cry1Ac/sck on Intestinal Microflor of Broiler Chicken%转Cry1Ac/sck基因糙米作为肉仔鸡日粮原料对肠道群的影响研究

    Institute of Scientific and Technical Information of China (English)

    秦海峰; 刘阳; 邢福国; 王会娟

    2012-01-01

    To assess whether the transgenic brown rice used in broiler's diet had any deleterious effects on intestinal micoflor of broiler chicken, a 42- day feeding trial was employed. Three hunder sixty one- day old broilers were divided into three groups. One group was fed a diet containing transgenic brown rice and the other group was fed a diet containing corresponding nontransgenic brown rice. Three groups were fed a diet containing corn. Entericmicroorganisms at the 21 and 42 day of age were determined. No histopathological damages were detected. From this study, it was concluded that there were no adverse effects of the transgenic brown rice on the broiler chicken's entericmicroorganisms. The transgenic brown rice used in broiler's diet was safe on entericmicroorganisms of brolier chicken.%为评价转Cry1Ac/sck基因糙米作为肉仔鸡日粮原料对肠道微生态的影响.将360只1日龄肉仔鸡随机分成3组,第一组饲喂含转基因糙米日粮;第二组饲喂含非转基因糙米日粮;第三组饲喂非转基因玉米日粮,试验期42天.在21、42天时测定肉仔鸡肠道菌群情况.结果表明:在实验期内,转基因糙米对肉仔鸡肠道菌群未产生明显影响.转Cry1Ac/sck基因糙米作为肉仔鸡日粮原料对肉仔鸡肠道微生态是安全的.

  10. Orientation behavior, development and survival of Trichoplusia ni (Lepidoptera: Noctuidae) larvae on cotton expressing Cry1Ac and Cry2Ab and conventional cotton.

    Science.gov (United States)

    This study was conducted to determine the effects of Bt cotton (Bollgard II) or a mixture of Bt+non-Bt cotton leaves on larval orientation behavior, survival and development of Trichoplusia ni in the laboratory. Results indicate that in a no-choice test, more first and fifth instars remained on Bt...

  11. Effect of pyramiding Bt and CpTI genes on resistance of cotton to Helicoverpa armigera (Lepidoptera: Noctuidae) under laboratory and field conditions

    NARCIS (Netherlands)

    Cui, J.J.; Luo, J.Y.; Werf, van der W.; Ma, Y.; Xia, J.Y.

    2011-01-01

    Transgenic cotton (Gossypium hirsutum L.) varieties, adapted to China, have been bred that express two genes for resistance to insects. the Cry1Ac gene from Bacillus thuringiensis (Berliner) (Bt), and a trypsin inhibitor gene from cowpea (CpTI). Effectiveness of the double gene modification in confe

  12. The recovery of Bt toxin content after temperature stress termination in transgenic cotton

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.; Wen, Y.; Zhang, X.; Wang, Y.; Chen, D.

    2013-06-01

    The insecticidal efficacy of Bt cotton under different environments has generated controversy in recent years. The objective of this study was to investigate possible reasons of the conflicting results caused by temperature stress. Two different types of Bt transgenic cotton cultivars (a Bt cultivar, Sikang1, and an hybrid Bt cultivar, Sikang3) were selected. The plants of the two Bt cultivars were exposed to high temperature (37 degree centigrade), low temperature (18 degree centigrade), and the control (27 degree centigrade) for short (24 h) and long (48 h) periods of stress at peak boll stage, and then moved to the glasshouse where the control plants were maintained. The results showed that the leaf insecticidal toxin content fully recovered within 24 h to the level of control after the end of short duration high-temperature treatment, and recovered mostly within 48 h of the termination of 24 h low-temperature stress. Under long duration high temperature treatment the Bt toxin content required longer recovery periods (48 and 72 h for Sikang3 and Sikang1, respectively) to reach the control level. The Bt protein content only recovered partially at 96 h after the end of the long-duration low-temperature stress, and the concentrations of the Cry1Ac protein were 74% and 77% of the corresponding control for Sikang1 and Sikang3, respectively. The different recovery and increase slowly of the leaf nitrogen metabolic rates after ceasing the heat and cold stress may be possible reason for the above difference. In summary, the duration and type of temperature (cold or heat) stress may cause different Bt insecticidal protein recovery rate due to different recovery rate of enzymes. (Author) 31 refs.

  13. Pyramids of QTLs enhance host–plant resistance and Bt-mediated resistance to leaf-chewing insects in soybean

    OpenAIRE

    Ortega, María A.; All, John N.; Boerma, H. Roger; Parrott, Wayne A.

    2016-01-01

    Key message QTL-M and QTL-E enhance soybean resistance to insects. Pyramiding these QTLs with cry1Ac increases protection against Bt-tolerant pests, presenting an opportunity to effectively deploy Bt with host–plant resistance genes. Abstract Plant resistance to leaf-chewing insects minimizes the need for insecticide applications, reducing crop production costs and pesticide concerns. In soybean [Glycine max (L.) Merr.], resistance to a broad range of leaf-chewing insects is found in PI 22935...

  14. Monarch larvae sensitivity to Bacillus thuringiensis- purified proteins and pollen

    OpenAIRE

    Hellmich, Richard L; Blair D Siegfried; Sears, Mark K.; Stanley-Horn, Diane E.; Daniels, Michael J.; Mattila, Heather R.; Spencer, Terrence; Bidne, Keith G.; Lewis, Leslie C.

    2001-01-01

    Laboratory tests were conducted to establish the relative toxicity of Bacillus thuringiensis (Bt) toxins and pollen from Bt corn to monarch larvae. Toxins tested included Cry1Ab, Cry1Ac, Cry9C, and Cry1F. Three methods were used: (i) purified toxins incorporated into artificial diet, (ii) pollen collected from Bt corn hybrids applied directly to milkweed leaf discs, and (iii) Bt pollen contaminated with corn tassel material applied directly to milkweed leaf discs. Bioassays of purified Bt tox...

  15. The effects of high temperature level on square Bt protein concentration of Bt cotton

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; CHEN Yuan; YAO Meng-hao; LI Yuan; WEN Yu-jin; ZHANG Xiang; CHEN De-hua

    2015-01-01

    Higher bol worm survival rates were detected after high temperature presented during square period in Bt cotton. The objective of this study was to investigate the effects of high temperature level on the Bt efifcacy of two different types of Bt cotton cultivars at squaring stage. During the 2011 to 2013 cotton growth seasons, high temperature treatments ranged from 34 to 44°C in climate chambers, and ifeld experiments under high temperature weather with various temperature levels were conducted to investigate the effects of the high temperature level on square Bt protein concentration and nitrogen metabolism. The climate chamber experiments showed that the square insecticidal protein contents reduced after 24 h elevated temperature treatments for both cultivars, whereas signiifcant declines of the square insecticidal protein contents were detected at temperature >38°C, and only slightly numerical reductions were observed when temperature below 38°C. Similar high temperature responses were also observed at the two ifeld experimental sites in 2013. Correspondingly, high temperature below 38°C seems have little effect on the square amino acid concentrations, soluble protein contents, glutam-ic-pyruvic transaminase (GPT) and glutamic-oxalacetic transaminase (GOT) activities as wel as protease and peptidase activities; however, when the temperature was above 38°C, reduced soluble protein contents, enhanced amino acid con-centrations, decreased GPT and GOT activities, bolstered protease and peptidase activities in square were detected. In general, the higher the temperature is (>38°C), the larger the changes for the above compound contents and key enzymes activities of the square protein cycle. The ifndings indicated that the unstable insect resistance of the square was related to high temperature level during square stage.

  16. Persistence of detectable insecticidal proteins from Bacillus thuringiensis (Cry) and toxicity after adsorption on contrasting soils.

    Science.gov (United States)

    Hung, T P; Truong, L V; Binh, N D; Frutos, R; Quiquampoix, H; Staunton, S

    2016-01-01

    Insecticidal Cry, or Bt, proteins are produced by the soil-endemic bacterium, Bacillus thuringiensis and some genetically modified crops. Their environmental fate depends on interactions with soil. Little is known about the toxicity of adsorbed proteins and the change in toxicity over time. We incubated Cry1Ac and Cry2A in contrasting soils subjected to different treatments to inhibit microbial activity. The toxin was chemically extracted and immunoassayed. Manduca sexta was the target insect for biotests. Extractable toxin decreased during incubation for up to four weeks. Toxicity of Cry1Ac was maintained in the adsorbed state, but lost after 2 weeks incubation at 25 °C. The decline in extractable protein and toxicity were much slower at 4 °C with no significant effect of soil sterilization. The major driving force for decline may be time-dependent fixation of adsorbed protein, leading to a decrease in the extraction yield in vitro, paralleled by decreasing solubilisation in the larval gut. PMID:26549751

  17. Effect of dual Bt-expression transformation vectors on transgene expression in tobacco.

    Science.gov (United States)

    Xu, L N; Dong, Y; Zhang, J; Wang, R X; Liu, H M; Yang, Q; Yang, M S

    2016-01-01

    This study aimed to determine the influence of vector structure on dual Bt gene expression and establish an efficient expression vector using Cry1Ac and Cry3A genes. Four vectors (N4, N5, N10, and S23) were developed and used for genetic transformation of tobacco to obtain insect-resistant transgenic lines. The vectors were constructed using the MAR structure, applying different promoter and enhancer sequences, and changing the transgene open-reading frame sequence. The average Cry1Ac toxalbumin expression quantity was 67 times higher in N5 than in N4 transgenic lines (8.77 and 0.13 μg/g, respectively). In contrast, the average Cry3A toxalbumin expression quantity was 1.5 times higher in N4 than in N5 lines (12.70 and 8.21 μg/g, respectively). The sequences of both Bt genes significantly influenced toxalbumin expression, although upstream Bt genes presented lower expression levels. The average Cry1Ac toxalbumin content was 13 times higher in the transgenic lines of AtADH 5'-non-translated sequence N5 (8.77 mg/g) than in the omega N10 lines (0.67 mg/g). Furthermore, the average Cry1Ac toxalbumin content was 5 times higher in MAR N5 than in non-MAR S23 lines (8.77 and 1.63 mg/g, respectively). The average Cry3A toxalbumin content was 1.3 times higher in N5 than in S23 lines (8.21 and 6.48 mg/g, respectively). Moreover, toxalbumin expression levels differed significantly among the S23-transformed lines. The MAR structure applied on both ends of the genes increased both the level and stability of exogenous gene expression. In conclusion, N5 was the most optimal of the four tested vectors. PMID:27525887

  18. Toxicity of Bacillus thuringiensis crystal proteins against eri silkworm, Samia cynthia ricini (Lepidoptera: Saturniidae).

    Science.gov (United States)

    Sandeep Kumar, Donthula; Tarakeswari, Muddanuru; Lakshminarayana, Maddukuri; Sujatha, Mulpuri

    2016-07-01

    Ten purified crystal proteins of Bacillus thuringiensis (Bt) were tested at concentrations ranging from 2.93 to 3000ng/cm(2) for their toxicity to eri silkworm through protein paint bioassays using castor leaves. Based on LC50 values, Cry1Aa (2.6ng/cm(2)) was highly toxic followed by Cry1Ac (29.3ng/cm(2)) and Cry1Ab (68.7ng/cm(2)). The Cry1Ca and Cry1Ea proteins were moderately toxic to eri silkworm larvae and resulted in 23% and 28% mortality, respectively at the highest concentration tested (3000ng/cm(2)). Only reduction in larval weight was observed with Cry2Aa, Cry1Da and Cry9Aa proteins while Cry3Aa and Cry1Ba proteins were found to be nontoxic. PMID:27377590

  19. Toxicity of Bacillus thuringiensis crystal proteins against eri silkworm, Samia cynthia ricini (Lepidoptera: Saturniidae).

    Science.gov (United States)

    Sandeep Kumar, Donthula; Tarakeswari, Muddanuru; Lakshminarayana, Maddukuri; Sujatha, Mulpuri

    2016-07-01

    Ten purified crystal proteins of Bacillus thuringiensis (Bt) were tested at concentrations ranging from 2.93 to 3000ng/cm(2) for their toxicity to eri silkworm through protein paint bioassays using castor leaves. Based on LC50 values, Cry1Aa (2.6ng/cm(2)) was highly toxic followed by Cry1Ac (29.3ng/cm(2)) and Cry1Ab (68.7ng/cm(2)). The Cry1Ca and Cry1Ea proteins were moderately toxic to eri silkworm larvae and resulted in 23% and 28% mortality, respectively at the highest concentration tested (3000ng/cm(2)). Only reduction in larval weight was observed with Cry2Aa, Cry1Da and Cry9Aa proteins while Cry3Aa and Cry1Ba proteins were found to be nontoxic.

  20. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein.

    Directory of Open Access Journals (Sweden)

    Wee Tek Tay

    2015-11-01

    Full Text Available The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the

  1. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein.

    Science.gov (United States)

    Tay, Wee Tek; Mahon, Rod J; Heckel, David G; Walsh, Thomas K; Downes, Sharon; James, William J; Lee, Sui-Fai; Reineke, Annette; Williams, Adam K; Gordon, Karl H J

    2015-11-01

    The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton) expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests) to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC) marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC) transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the detailed mode

  2. [Advances in effects of insecticidal crystal proteins released from transgenic Bt crops on soil ecology].

    Science.gov (United States)

    Zhou, Xue-Yong; Liu, Ning; Zhao, Man; Li, He; Zhou, Lang; Tang, Zong-Wen; Cao, Fei; Li, Wei

    2011-05-01

    With the large scale cultivation of transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal crystal proteins in the world, the problem of environmental safety caused by these Bt crops has received extensive attention. These insecticidal crystal proteins can be released into the soil continuously in the growing period of Bt plants. If their accumulation of the insecticidal crystal proteins exceeds consumption by insect larvae and degradation by the environmental factors, these insecticidal crystal proteins could constitute a hazard to non-target insects and soil microbiota. There are three main ways to release insecticidal crystal proteins into soil for Bt plants: root exudates, pollen falling, and crop reside returning. The Bt insecticidal crystal proteins released into soil can be adsorbed rapidly by active soil particles and the absorption equilibrium attained within 1-3 h. The adsorption protects Bt insecticidal crystal proteins against soil microbial degradation or enzyme degradation, which leads to remarkable prolong of the persistence of insecticidal activity. The change of soil microorganism species is an important index for evaluating the effect of Bt plants on soil ecology. The research showed that these insecticidal crystal proteins released by the Bt plant root exudates or Bt organism had no toxicity to the soil earthworms, nematodes, protozoa, bacteria and fungi; however, it could reduce the mycelium length of the arbuscular mycorrhizal fungi (AMF) and restrain AMF to form invasion unit. The influencing degree of Bt protein on soil enzyme activity varied with the releasing modes or growth period of Bt crops. Bt Cry1Ab protein can be taken up from soil by parts of following crops; however, different results were obtained with different commercial kits. To better understand the soil ecological evaluation about the insecticidal crystal proteins released from transgenic Bt crops, this review provides a comprehensive overview about the release

  3. 用合成多肽为半抗原制备Bt Cry1Ab的单克隆抗体%Preparation of the Monoclonal Antibody Against Bt Cry1Ab by Using Synthetic Peptide as Hapten

    Institute of Scientific and Technical Information of China (English)

    胡小元; 张岐蜀; 段伟; 姜国华; 李玲

    2013-01-01

    由于Bt Cry1Aa、Cry1Ab和Cry1Ac晶体蛋白之间具有很高的同源性(82%~90%),采用常规的单抗制备方法很难制取特异性强的Bt Cry1Ab单抗,为了制备抗Bt Cry1Ab蛋白的特异性单克隆抗体(MAB),本研究从NCBI获得了Bt Cry1Ab蛋白的氨基酸序列,根据ANTHEPORT和DNAStar软件对其抗原性、亲水性和表位性分析结果选定Bt Cry1Ab特异性肽段进行人工合成,并将其偶联于匙孔血蓝蛋白(KLH)免疫动物,应用细胞融合技术制备了抗该肽段的杂交瘤细胞22株.通过ELISA试验从中筛选出与Bt Cry1Ab天然蛋白产生特异性反应的单克隆抗体杂交瘤细胞株一株(3A10).经检测,其分泌的抗体亚类为IgG1型;轻链属κ型;杂交瘤细胞株染色体数目为89~108条;用其制作的腹水对Bt Cry1Ab合成肽的反应效价为1∶1×107;对Bt Cry1Ab天然蛋白的反应效价为1∶1×104;纯化后的抗体对Bt Cry1Ab合成肽的效价为1∶1×108;对Bt Cry1Ab天然蛋白的效价为1∶2×104.抗体的相对亲和力为0.5 μg/mL,对Bt Cry 1Ab蛋白的最低可检测值为10 ng/mL.ELISA结果显示,3A10杂交瘤细胞株所分泌的MAB能特异性识别合成肽和Bt Cry1Ab蛋白,而对同源的Cry1Ac和Cry1Aa蛋白无交叉反应;本研究所制备的Bt Cry1Ab单克隆抗体能够对常规棉和抗虫棉(Gossypium hirsutum L.)进行有效的区分,并且能特异性的识别其中的Bt Cry1Ab蛋白.%Because Bt Cry 1Aa, Cry 1Ab and Cry 1Ac share high sequence identity(82%~90%), it is difficult to prepare Bt Cry1 Ab monoclonal antibody that has highly specific by using conventional method. In order to prepare monoclonal antibody against Bt Cry1Ab, we acquired the amino acid sequence of Bt Cry1Ab protein from NCBI. According to the antigenicity, hydrophilicity and accessibility analyzed results by ANTHEPORT and DNAStar computer software, the specific peptide of Bt Cry1Ab was synthesized by a chemical process. The Bt Cry1Ab peptide was linked with carrier

  4. Cry1Ac毒蛋白质对亚洲玉米螟幼虫几种酶活性的影响%Effects of Cry1Ac toxin on activities of some enzymes in larvae of the Asian corn borer, Ostrinia furnacalis (Güenée) (Lepidoptera :Pyralidae)

    Institute of Scientific and Technical Information of China (English)

    周琼; 黄东林; 祁静霞; 吴海燕; 杨丽芬; 施敏娟; 杨益众

    2013-01-01

    为探索Cry1Ac毒蛋白质与亚洲玉米螟[Ostrinia furnacalis (Güenée)]体内解毒酶间的关系及Cry1Ac作用下保护酶间的平衡关系,室内配制不同Cry1Ac毒蛋白质含量(200 ng/g、500 ng/g、800 ng/g、1 100 ng/g)的人工饲料饲喂亚洲玉米螟幼虫,用分光光度法测定了3龄和5龄幼虫体内乙酰胆碱酯酶、α-乙酸萘酯酶、羧酸酯酶、谷胱甘肽-S-转移酶、超氧化物歧化酶和过氧化氢酶的活性.结果表明:1 100 ng/g毒蛋白质处理的3龄幼虫乙酰胆碱酯酶活性显著高于对照和其他处理,800 ng/g处理的该酶活性显著高于200 ng/g处理,1 100 ng/g毒蛋白质处理的5龄幼虫的该酶活性显著高于200 ng/g处理.1 100 ng/g处理3、5龄幼虫的α-乙酸萘酯酶活性均显著低于对照和其他处理,800 ng/g处理的3龄幼虫该酶活性显著低于对照和200 ng/g处理,500 ng/g处理的该酶活性显著低于200 ng/g处理.1100 ng/g、800 ng/g、500 ng/g处理的3龄幼虫羧酸酯酶活性显著低于对照,1 100 ng/g处理的5龄幼虫该酶活性显著低于对照和200 ng/g处理.1100 ng/g、800 ng/g、500 ng/g处理的3龄幼虫谷胱甘肽转移酶活性显著低于200 ng/g处理,1 100 ng/g处理的5龄幼虫该酶活性显著低于对照.500 ng/g、800 ng/g处理3龄幼虫的超氧化物歧化酶活性显著高于对照.500 ng/g、800 ng/g、1 100 ng/g处理的3龄幼虫过氧化氢酶活性显著低于对照,800 ng/g、1100 ng/g处理的该酶活性显著低于200 ng/g处理,1100 ng/g处理的5龄幼虫该酶活性显著低于对照和200 ng/g处理.可见,不同含量Cry1Ac毒蛋白质处理的亚洲玉米螟体内,除5龄幼虫超氧化物歧化酶外,其他酶的活性在处理间均有显著变化.%In order to discuss the relationship between Cry1Ac toxin and detoxification enzymes,and the balance of protective enzymes affected by Cry1Ac in Asian corn borer,Ostrinia furnacalis (Guenée),the activities of acetylcholinesterase,α-naphthyl acetate

  5. Hematotoxicity and genotoxicity evaluations in Swiss mice intraperitoneally exposed to Bacillus thuringiensis (var kurstaki) spore crystals genetically modified to express individually Cry1Aa, Cry1Ab, Cry1Ac, or Cry2Aa.

    Science.gov (United States)

    Mezzomo, Bélin Poletto; Miranda-Vilela, Ana Luisa; Barbosa, Lilian Carla Pereira; Albernaz, Vanessa Lima; Grisolia, Cesar Koppe

    2016-08-01

    Bacillus thuringiensis (Bt) has been widely used in foliar sprays as part of integrated pest management strategies against insect pests of agricultural crops. Since the advent of genetically modified plants expressing Bt δ-endotoxins, the bioavailability of Cry proteins has increased, and therefore for biosafety reasons their adverse effects should be studied, mainly for nontarget organisms. We evaluated, in Swiss mice, the hematotoxicity and genotoxicity of the genetically modified strains of Bt spore crystals Cry1Aa, 1Ab, 1Ac, or 2Aa at 27 mg/kg, and Cry1Aa, 1Ab and 2Aa also at 136 and 270 mg/kg, administered with a single intraperitoneal injection 24 h before euthanasia. Controls received filtered water or cyclophosphamide. Blood samples collected by cardiac puncture were used to perform hemogram, and bone marrow was extracted for the micronucleus test. Bt spore crystals presented toxicity for lymphocytes when in higher doses, which varied according to the type of spore crystal studied, besides promoting cytotoxic and genotoxic effects for the erythroid lineage of bone marrow, mainly at highest doses. Although the profile of such adverse side effects can be related to their high level of exposure, which is not commonly found in the environment, results indicated that these Bt spore crystals were not harmless to mice. This suggests that a more specific approach should be taken to increase knowledge about their toxicological properties and to establish the toxicological risks to nontarget organisms. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 970-978, 2016.

  6. [Advances in safety studies of soil Bt toxin proteins released from transgenic Bt crops].

    Science.gov (United States)

    Bai, Yaoyu; Jiang, Mingxing; Cheng, Jia; Jiang, Yonghou

    2003-11-01

    Commercialized transgenic Bt (Bacillus thuringiensis) crops are permitted for field growth in a large scale, which leads to significant issues of ecological risk assessment in soil ecosystem. In this paper, some general safety problems involving in the soil Bt active toxins released from insect-resistant transgenic Bt crops in the forms of plant residues, root exudates and pollens were reviewed, including their adsorption by soil active-particles, their insecticidal activity, persistence, and biodegradation by soil microbes, and their effects on soil organisms.

  7. Binding site alteration is responsible for field-isolated resistance to Bacillus thuringiensis Cry2A insecticidal proteins in two Helicoverpa species.

    Directory of Open Access Journals (Sweden)

    Silvia Caccia

    Full Text Available BACKGROUND: Evolution of resistance by target pests is the main threat to the long-term efficacy of crops expressing Bacillus thuringiensis (Bt insecticidal proteins. Cry2 proteins play a pivotal role in current Bt spray formulations and transgenic crops and they complement Cry1A proteins because of their different mode of action. Their presence is critical in the control of those lepidopteran species, such as Helicoverpa spp., which are not highly susceptible to Cry1A proteins. In Australia, a transgenic variety of cotton expressing Cry1Ac and Cry2Ab (Bollgard II comprises at least 80% of the total cotton area. Prior to the widespread adoption of Bollgard II, the frequency of alleles conferring resistance to Cry2Ab in field populations of Helicoverpa armigera and Helicoverpa punctigera was significantly higher than anticipated. Colonies established from survivors of F(2 screens against Cry2Ab are highly resistant to this toxin, but susceptible to Cry1Ac. METHODOLOGY/PRINCIPAL FINDINGS: Bioassays performed with surface-treated artificial diet on neonates of H. armigera and H. punctigera showed that Cry2Ab resistant insects were cross-resistant to Cry2Ae while susceptible to Cry1Ab. Binding analyses with (125I-labeled Cry2Ab were performed with brush border membrane vesicles from midguts of Cry2Ab susceptible and resistant insects. The results of the binding analyses correlated with bioassay data and demonstrated that resistant insects exhibited greatly reduced binding of Cry2Ab toxin to midgut receptors, whereas no change in (125I-labeled-Cry1Ac binding was detected. As previously demonstrated for H. armigera, Cry2Ab binding sites in H. punctigera were shown to be shared by Cry2Ae, which explains why an alteration of the shared binding site would lead to cross-resistance between the two Cry2A toxins. CONCLUSION/SIGNIFICANCE: This is the first time that a mechanism of resistance to the Cry2 class of insecticidal proteins has been reported

  8. 转苏云金杆菌毒蛋白基因玉米植株的获得及其抗虫性分析%Maize Transformation of cry1Ac3 Gene and Insect Resistance of Their Transgenic Plants

    Institute of Scientific and Technical Information of China (English)

    李慧芬; 李旭刚; 刘翔; 常团结; 肖桂芳; 朱祯

    2002-01-01

    The success for genetic transformation of maize (Zea mays L.) is highly related to genotype of target material.A few model varieties can be induced into type Ⅱ callus,which can be easily transformed with high regeneration frequency.However,most of cultivars could be only induced into type Ⅰ callus,which is difficult to be transformed with low regeneration.Thus,studying on the conditions of induction and transformation for type Ⅰ callus will show great importance for improving elite of maize directly with genetic engineering.Bacillus thuringiensis toxin protein (cry1Ac3) gene was successfully delivered into type Ⅰ calli of two elite inbred lines of maize,340 and E28,via particle bombardment in this work.Fertile transgenic corn plants were obtained through phosphinothricin (PPT) or hygromycin B (HygB) selection,and the results of PCR,Southern blot assay and ELISA showed that foreign genes had been integrated into maize genome and expressed.In the meantime,strong resistance of some transgenic plants to corn borer was showed through bioassay.In addition,the comparison of selective effect between PPT and HygB showed that PPT,as a selective agent,was better than HygB for the growth and regeneration of resistant calli.%玉米( Zea mays L.)转化成功与否与基因型密切相关.在转化过程中,除少数模式品种能够形成再生频率较高且易转化的Ⅱ型愈伤组织外,大多数栽培品种往往只能够形成再生频率较低且不易转化的Ⅰ型愈伤组织.因此探索Ⅰ型愈伤组织的诱导及其转化条件,提高转化效率,对直接改良玉米优良自交系具有重要意义.应用基因枪转化技术将苏云金杆菌( Bacillus thuringiensis ) cry1Ac3基因导入玉米优良自交系E28及340的Ⅰ型胚性愈伤组织中,经过膦丝菌素(PPT)或潮霉素(HygB)筛选,获得了再生植株.经PCR检测、Southern blot分析及Bt毒蛋白ELISA检测证实,外源基因已整合到玉米基因组中,并已获得表达.抗虫性

  9. Hematotoxicity and genotoxicity evaluations in Swiss mice intraperitoneally exposed to Bacillus thuringiensis (var kurstaki) spore crystals genetically modified to express individually Cry1Aa, Cry1Ab, Cry1Ac, or Cry2Aa.

    Science.gov (United States)

    Mezzomo, Bélin Poletto; Miranda-Vilela, Ana Luisa; Barbosa, Lilian Carla Pereira; Albernaz, Vanessa Lima; Grisolia, Cesar Koppe

    2016-08-01

    Bacillus thuringiensis (Bt) has been widely used in foliar sprays as part of integrated pest management strategies against insect pests of agricultural crops. Since the advent of genetically modified plants expressing Bt δ-endotoxins, the bioavailability of Cry proteins has increased, and therefore for biosafety reasons their adverse effects should be studied, mainly for nontarget organisms. We evaluated, in Swiss mice, the hematotoxicity and genotoxicity of the genetically modified strains of Bt spore crystals Cry1Aa, 1Ab, 1Ac, or 2Aa at 27 mg/kg, and Cry1Aa, 1Ab and 2Aa also at 136 and 270 mg/kg, administered with a single intraperitoneal injection 24 h before euthanasia. Controls received filtered water or cyclophosphamide. Blood samples collected by cardiac puncture were used to perform hemogram, and bone marrow was extracted for the micronucleus test. Bt spore crystals presented toxicity for lymphocytes when in higher doses, which varied according to the type of spore crystal studied, besides promoting cytotoxic and genotoxic effects for the erythroid lineage of bone marrow, mainly at highest doses. Although the profile of such adverse side effects can be related to their high level of exposure, which is not commonly found in the environment, results indicated that these Bt spore crystals were not harmless to mice. This suggests that a more specific approach should be taken to increase knowledge about their toxicological properties and to establish the toxicological risks to nontarget organisms. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 970-978, 2016. PMID:25899034

  10. The presence of Bt-transgenic oilseed rape in wild mustard populations affects plant growth.

    Science.gov (United States)

    Liu, Yongbo; Stewart, C Neal; Li, Junsheng; Huang, Hai; Zhang, Xitao

    2015-12-01

    The adventitious presence of transgenic plants in wild plant populations is of ecological and regulatory concern, but the consequences of adventitious presence are not well understood. Here, we introduced Bacillus thuringiensis Cry1Ac (Bt)-transgenic oilseed rape (Bt OSR, Brassica napus) with various frequencies into wild mustard (Brassica juncea) populations. We sought to better understand the adventitious presence of this transgenic insecticidal crop in a wild-relative plant population. We assessed the factors of competition, resource availability and diamondback moth (Plutella xylostella) infestation on plant population dynamics. As expected, Bt OSR performed better than wild mustard in mixed populations under herbivore attack in habitats with enough resources, whereas wild mustard had higher fitness when Bt OSR was rarer in habitats with limited resources. Results suggest that the presence of insect-resistant transgenic plants could decrease the growth of wild mustard and Bt OSR plants and their populations, especially under high herbivore pressure. PMID:26338267

  11. The natural refuge policy for Bt cotton (Gossypium L. in Pakistan – a situation analysis

    Directory of Open Access Journals (Sweden)

    Muhammad Sajjad Ali

    2013-07-01

    Full Text Available Bt cotton (event Cry1Ac was formally commercialized in Pakistan in 2010. However, there has been an increasing trend of planting unauthorized Bt cotton germplasm in farmers' fields since 2003 with a high rate of adoption in the core cotton areas especially in the province Punjab. The transgenic cotton technology has provided the growers with substantial economic benefits and has reduced their dependence on pesticides for pest control, especially against Helicoverpa armigera (Hubner. However, keeping in view the capacity of this insect to develop resistance against novel chemical formulations, it is easily speculated that Bt toxin, too, is no exception. Refuge crop policy for mono transgenic crop events has helped in delaying the rate of resistance evolution in the target pests. Thus, in Pakistan, where planting of structured refuge crops along Bt cotton fields is not mandatory, the effectiveness and durability of Bt cotton technology may decrease due to a number of factors which are discussed in this review.

  12. Synergism and Antagonism between Bacillus thuringiensis Vip3A and Cry1 Proteins in Heliothis virescens, Diatraea saccharalis and Spodoptera frugiperda

    Science.gov (United States)

    Lemes, Ana Rita Nunes; Davolos, Camila Chiaradia; Legori, Paula Cristina Brunini Crialesi; Fernandes, Odair Aparecido; Ferré, Juan; Lemos, Manoel Victor Franco; Desiderio, Janete Apparecida

    2014-01-01

    Second generation Bt crops (insect resistant crops carrying Bacillus thuringiensis genes) combine more than one gene that codes for insecticidal proteins in the same plant to provide better control of agricultural pests. Some of the new combinations involve co-expression of cry and vip genes. Because Cry and Vip proteins have different midgut targets and possibly different mechanisms of toxicity, it is important to evaluate possible synergistic or antagonistic interactions between these two classes of toxins. Three members of the Cry1 class of proteins and three from the Vip3A class were tested against Heliothis virescens for possible interactions. At the level of LC50, Cry1Ac was the most active protein, whereas the rest of proteins tested were similarly active. However, at the level of LC90, Cry1Aa and Cry1Ca were the least active proteins, and Cry1Ac and Vip3A proteins were not significantly different. Under the experimental conditions used in this study, we found an antagonistic effect of Cry1Ca with the three Vip3A proteins. The interaction between Cry1Ca and Vip3Aa was also tested on two other species of Lepidoptera. Whereas antagonism was observed in Spodoptera frugiperda, synergism was found in Diatraea saccharalis. In all cases, the interaction between Vip3A and Cry1 proteins was more evident at the LC90 level than at the LC50 level. The fact that the same combination of proteins may result in a synergistic or an antagonistic interaction may be an indication that there are different types of interactions within the host, depending on the insect species tested. PMID:25275646

  13. Caracterización de la expresión de la proteína Cry1Ac en diferentes tejidos de cuatro clones transgénicos de dos variedades en papa / Characterization of Cry1Ac protein expresión in different tissues of four transgenic clones in two potato varieties

    OpenAIRE

    Vanegas Araújo, Pablo Andrés

    2009-01-01

    La papa (Solanum sp.) es el cuarto producto alimenticio más importante a nivel mundial, en Colombia anualmente se producen alrededor de 2,8 millones de toneladas sirviendo como sustento económico a 90000 familias. En el país, Tecia solanivora genera el mayor impacto económico en el cultivo con pérdidas de hasta el 100% en la producción de tubérculos. El fitomejoramiento genético vía introducción de genes Cry, que codifican para cristales proteicos insecticidas, constituye una alternativa para...

  14. Effects of Transgenic Brown Rice on Nutritional of Broiler Chicken%转Cry1Ac/sck基因糙米作为肉仔鸡日粮原料的营养安全性评价

    Institute of Scientific and Technical Information of China (English)

    秦海峰; 刘阳; 邢福国

    2011-01-01

    A 42-day feeding trial was employed to evaluate whether the transgenic brown rice used in broiler' s diet had any deleterious effects on gowth performance, on organ index, on carcass trait, on composition of muscle of broiler chicken. Three hunder sixty one-day old broilers were divided into three groups. One group was fed a diet containing transgenic brown rice and the other group was fed a diet containing corresponding nontransgenic brown rice. Three group was fed a diet containing corn. Growth Performance and organ index at the 21 and 42 day of age were determined, carcass trait and composition of muscle were measured at the end of the experiment. The results showed that no significant difference were observed(P>0.05) in the growth performance, in organ index and carcass trait and composition of muscle in two phases between the two groups. No histopathological damages were detected. From this study, it was concluded that there were no adverse effects of the transgenic brown rice on the broiler chicken' s health.%为了研究转Cry1Ac/sck基因糙米作为肉仔鸡日粮原料的营养安全性,将360只1日龄肉仔鸡随机分成3组.一组饲喂含转基因糙米日粮,另一组饲喂含非转基因糙米日粮,第三组饲喂非转基因玉米日粮.试验期42 d.测定肉仔鸡的生产性能,器官指数,屠体性状,肌肉成分,21,42 d测定生产性能,器官指数.42 d测定屠体性状和肌肉成分.结果显示,转基因糙米对肉仔鸡的生产性能、器官指数、屠体性状、肌肉成分和健康状况在试验期内未产生明显的有害影响(P>0.05).

  15. Insecticidal activity of residual Bt protein at the second trophic level

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Measurements were taken of Bt protein expressed in the leaves of transgenic cotton (Gossypium hirsutum) transformed with a synthesized Bt (Bacillus thuringiensis) cry1A gene and its persistent level in larval bodies and faeces of a non-targeted insect pest, beet armyworm (Spodoptera exigua). We performed enzyme linked immunosorbent assays (ELISA) and bioassays using neonate larvae of cotton bollworm (Helicoverpa armigera) to detect the insecticidal activity of residual Bt protein at the second trophic level. The results showed that Bt protein content in functional leaves was different at various developmental stages and was different among plants at the same stage. Even though Bt protein concentration in the larval bodies and faeces decreased 97.5%-99% compared to that found in cotton leaves subsequently fed to beet armyworm larvae, it still had a lethal effect on neonate cotton bollworm larvae. Therefore, Bt protein present at the second trophic level had insecticidal activity. This result is important in understanding and predicting the effect of transgenic plants on nontarget organisms.

  16. Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.

    Directory of Open Access Journals (Sweden)

    Rose Monnerat

    Full Text Available Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab. Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.

  17. Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.

    Science.gov (United States)

    Monnerat, Rose; Martins, Erica; Macedo, Cristina; Queiroz, Paulo; Praça, Lilian; Soares, Carlos Marcelo; Moreira, Helio; Grisi, Isabella; Silva, Joseane; Soberon, Mario; Bravo, Alejandra

    2015-01-01

    Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda. PMID:25830928

  18. Estudio de libertad de operación de la línea transgénica de papa Cry1Ac desarrollada por Corporación de Investigaciones Biológicas y la Universidad Nacional de Colombia Sede Medellín

    OpenAIRE

    Hincapié Rojas, Viviana Patricia

    2012-01-01

    El ámbito de esta investigación de tipo descriptivo, está relacionada con la búsqueda de los documentos técnicos, de propiedad intelectual y reglamentarios, que existen alrededor del desarrollo de una línea transgénica de papa Cry 1Ac generada por la Corporación de Ciencias Biológicas (CIB) y la Universidad Nacional de Colombia Sede Medellín (UNCSM), para que una vez culminen los estudios de bioseguridad, y se obtenga un producto, este pueda ser comercializado sin infringir derechos de tercer...

  19. Bt resistance in Australian insect pest species.

    Science.gov (United States)

    Downes, Sharon; Walsh, Tom; Tay, Wee Tek

    2016-06-01

    Bt cotton was initially deployed in Australia in the mid-1990s to control the polyphagous pest Helicoverpa armigera (Hübner) which was intractably resistant to synthetic chemistries. A conservative strategy was enforced and resistance to first generation single toxin technology was managed. A decade later, shortly after the release of dual toxin cotton, high baseline frequencies of alleles conferring resistance to one of its components prompted a reassessment of the thinking behind the potential risks to this technology. Several reviews detail the characteristics of this resistance and the nuances of deploying first and second generation Bt cotton in Australia. Here we explore recent advances and future possibilities to estimate Bt resistance in Australian pest species and define what we see as the critical data for enabling effective pre-emptive strategies. We also foreshadow the imminent deployment of three toxin (Cry1Ac, Cry2Ab, Vip3A) Bollgard 3 cotton, and examine aspects of resistance to its novel component, Vip3A, that we believe may impact on its stewardship. PMID:27436735

  20. Characterization of a Chitin-Binding Protein from Bacillus thuringiensis HD-1.

    Directory of Open Access Journals (Sweden)

    Naresh Arora

    Full Text Available Strains of Bacillus thuringiensis produce insecticidal proteins. These strains have been isolated from diverse ecological niches, such as soil, phylloplane, insect cadavers and grain dust. To effectively propagate, these strains produce a range of molecules that facilitate its multiplication in a competing environment. In this report, we have examined synthesis of a chitin-binding protein and evaluated its effect on fungi encountered in environment and its interaction with insecticidal proteins synthesized by B. thuringiensis. The gene encoding chitin-binding protein has been cloned and expressed. The purified protein has been demonstrated to interact with Cry insecticidal protein, Cry1Ac by Circular Dichrosim spectroscopy (CD and in vitro pull down assays. The chitin-binding protein potentiates insecticidal activity of bacillar insecticidal protein, Cry1Ac. Further, chitin-binding protein was fungistatic against several soil fungi. The chitin binding protein is expressed in spore mother cell and deposited along with insecticidal protein, Cry1Ac. It interacts with Cry1Ac to potentiate its insecticidal activity and facilitate propagation of Bacillus strain in environment by inhibiting growth of certain fungi.

  1. A high-throughput liquid bead array-based screening technology for Bt presence in GMO manipulation.

    Science.gov (United States)

    Fu, Wei; Wang, Huiyu; Wang, Chenguang; Mei, Lin; Lin, Xiangmei; Han, Xueqing; Zhu, Shuifang

    2016-03-15

    The number of species and planting areas of genetically modified organisms (GMOs) has been rapidly developed during the past ten years. For the purpose of GMO inspection, quarantine and manipulation, we have now devised a high-throughput Bt-based GMOs screening method based on the liquid bead array. This novel method is based on the direct competitive recognition between biotinylated antibodies and beads-coupled antigens, searching for Bt presence in samples if it contains Bt Cry1 Aa, Bt Cry1 Ab, Bt Cry1 Ac, Bt Cry1 Ah, Bt Cry1 B, Bt Cry1 C, Bt Cry1 F, Bt Cry2 A, Bt Cry3 or Bt Cry9 C. Our method has a wide GMO species coverage so that more than 90% of the whole commercialized GMO species can be identified throughout the world. Under our optimization, specificity, sensitivity, repeatability and availability validation, the method shows a high specificity and 10-50 ng/mL sensitivity of quantification. We then assessed more than 1800 samples in the field and food market to prove capacity of our method in performing a high throughput screening work for GMO manipulation. Our method offers an applicant platform for further inspection and research on GMO plants.

  2. A high-throughput liquid bead array-based screening technology for Bt presence in GMO manipulation.

    Science.gov (United States)

    Fu, Wei; Wang, Huiyu; Wang, Chenguang; Mei, Lin; Lin, Xiangmei; Han, Xueqing; Zhu, Shuifang

    2016-03-15

    The number of species and planting areas of genetically modified organisms (GMOs) has been rapidly developed during the past ten years. For the purpose of GMO inspection, quarantine and manipulation, we have now devised a high-throughput Bt-based GMOs screening method based on the liquid bead array. This novel method is based on the direct competitive recognition between biotinylated antibodies and beads-coupled antigens, searching for Bt presence in samples if it contains Bt Cry1 Aa, Bt Cry1 Ab, Bt Cry1 Ac, Bt Cry1 Ah, Bt Cry1 B, Bt Cry1 C, Bt Cry1 F, Bt Cry2 A, Bt Cry3 or Bt Cry9 C. Our method has a wide GMO species coverage so that more than 90% of the whole commercialized GMO species can be identified throughout the world. Under our optimization, specificity, sensitivity, repeatability and availability validation, the method shows a high specificity and 10-50 ng/mL sensitivity of quantification. We then assessed more than 1800 samples in the field and food market to prove capacity of our method in performing a high throughput screening work for GMO manipulation. Our method offers an applicant platform for further inspection and research on GMO plants. PMID:26499065

  3. Biological activity of Bt proteins expressed in different structures of transgenic corn against Spodoptera frugiperda

    Directory of Open Access Journals (Sweden)

    Daniel Bernardi

    2016-06-01

    Full Text Available ABSTRACT: Spodoptera frugiperda (J. E. Smith is the main target pest of Bt corn technologies, such as YieldGard VT PRO(tm (Cry1A.105/Cry2Ab2 and PowerCore(tm (Cry1A.105/Cry2Ab2/Cry1F. In this study, it was evaluated the biological activity of Bt proteins expressed in different plant structures of YieldGard VT PRO(tm and PowerCore(tm corn against S. frugiperda . Complete mortality of S. frugiperda neonates was observed on leaf-disc of both Bt corn technologies. However, the mortality in silks and grains was lower than 50 and 6%, respectively. In addition, more than 49% of the surviving larvae in silks and grains completed the biological cycle. However, all life table parameters were negatively affected in insects that developed in silks and grains of both Bt corn events. In summary, the low biological activity of Bt proteins expressed on silks and grains of YieldGard VT PRO(tm and PowerCore(tm corn can contribute to the resistance evolution in S. frugiperda populations.

  4. Continuous evolution of Bacillus thuringiensis toxins overcomes insect resistance.

    Science.gov (United States)

    Badran, Ahmed H; Guzov, Victor M; Huai, Qing; Kemp, Melissa M; Vishwanath, Prashanth; Kain, Wendy; Nance, Autumn M; Evdokimov, Artem; Moshiri, Farhad; Turner, Keith H; Wang, Ping; Malvar, Thomas; Liu, David R

    2016-05-01

    The Bacillus thuringiensis δ-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. Here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest Trichoplusia ni (TnCAD) that is not natively bound by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (dissociation constant Kd = 11-41 nM), kill TnCAD-expressing insect cells that are not susceptible to wild-type Cry1Ac, and kill Cry1Ac-resistant T. ni insects up to 335-fold more potently than wild-type Cry1Ac. Our findings establish that the evolution of Bt toxins with novel insect cell receptor affinity can overcome insect Bt toxin resistance and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects. PMID:27120167

  5. Continuous evolution of Bacillus thuringiensis toxins overcomes insect resistance.

    Science.gov (United States)

    Badran, Ahmed H; Guzov, Victor M; Huai, Qing; Kemp, Melissa M; Vishwanath, Prashanth; Kain, Wendy; Nance, Autumn M; Evdokimov, Artem; Moshiri, Farhad; Turner, Keith H; Wang, Ping; Malvar, Thomas; Liu, David R

    2016-05-01

    The Bacillus thuringiensis δ-endotoxins (Bt toxins) are widely used insecticidal proteins in engineered crops that provide agricultural, economic, and environmental benefits. The development of insect resistance to Bt toxins endangers their long-term effectiveness. Here we have developed a phage-assisted continuous evolution selection that rapidly evolves high-affinity protein-protein interactions, and applied this system to evolve variants of the Bt toxin Cry1Ac that bind a cadherin-like receptor from the insect pest Trichoplusia ni (TnCAD) that is not natively bound by wild-type Cry1Ac. The resulting evolved Cry1Ac variants bind TnCAD with high affinity (dissociation constant Kd = 11-41 nM), kill TnCAD-expressing insect cells that are not susceptible to wild-type Cry1Ac, and kill Cry1Ac-resistant T. ni insects up to 335-fold more potently than wild-type Cry1Ac. Our findings establish that the evolution of Bt toxins with novel insect cell receptor affinity can overcome insect Bt toxin resistance and confer lethality approaching that of the wild-type Bt toxin against non-resistant insects.

  6. Degradation of Cry1Ab Protein Within Transgenic Bt Maize Tissue by Composite Microbial System of MC1

    Institute of Scientific and Technical Information of China (English)

    Meng Yao; Gu Wan-rong; Ye Le-fu; Chen Dong-sheng; Li Jing; Wei Shi

    2014-01-01

    Environmental safety issues involved in transgenic plants have become the concern of researchers, practitioners and policy makers in recent years. Potential differences between Bt maize (ND1324 and ND2353 expressing the insecticidal Cry1Ab protein) and near-isogenic non-Bt varieties (ND1392 and ND223) in their influence on the composite microbial system of MC1 during the fermentation process were studied during 2011-2012. Cry1Ab protein in Bt maize residues didn't affect characteristics of lignocellulose degradation by MC1, pH of fermentation broth decreasing at initial stage and increasing at later stage of degradation. The quality of various volatile products in fermentation broth showed that no significant difference of residues fermentation existed between Bt maize and non-Bt maize. During the fermentation MC1 efficiently degraded maize residues by 83%-88%, and cellulose, hemicelluloses and lignin content decreased by 70%-72%, 72%-75% and 30%-37%, respectively. Besides that, no consistent difference was found between Bt and non-Bt maize residues lignocellulose degradation by MC1 during the fermentation process. MC1 degraded 88%-89% Cry1Ab protein in Bt maize residues, and in the fermentation broth of MC1 and bacteria of MC1 Cry1Ab protein was not detected. DGGE profile analyses revealed that the microbial community drastically changed during 1-3 days and became stable until the 9th day. Though the dominant strains at different fermentation stages had significantly changed, no difference on the dominant strains was observed between Bt and non-Bt maize at different stages. Our study indicated that Cry1Ab protein did not influence the growth characteristic of MC1.

  7. Bt基因和Bt蛋白检测技术研究进展%Research on Progress of the Detection of BT Protein and BT Gene

    Institute of Scientific and Technical Information of China (English)

    汪倩; 向晓玲; 许耀心; 倪晓强; 姜佳燕; 龚云飞

    2012-01-01

    BT protein is a kind of specific insecticidal activity of protein crystallization produced by bacillus. Through the transgenic technology, we switch Bt gene into the crops such as rice and soybean to cultivate a good resistance to insects breed, then without using pesticides and some other harmful substances, the plant diseases and insect pests can be prevented and cured efficiently. However, animal experiment and clinical study found that Bt protein may damage mammalian immune organs and immune cells, and may also influence the genetic structure of the gene pool and genetic diversity of the popula- tion. It also has serious influence on the soil specific organisms function, soil biodiversity, and the soil enzyme activity and so on. What' s more, Bt protein in transgenic rice may enrich in human bodies along the food chain and do potential harm to humans. Therefore, the research on detecting of Bt genc or protein is necessary. So, the research status of Bt gene and pro- tein are briefly reviewed in this paper.%通过转基因技术将可表达杀虫特性蛋白的Bt基因转入大豆、水稻等农作物中,培育出优良的抗虫品种,从而在不使用农药等有害物质的前提下,对病虫害起到高效防治作用。然而动物试验及临床研究发现,Bt蛋白可能导致哺乳动物的免疫器官和免疫细胞损伤,也可能影响基因库的遗传结构及群体遗传多样性,对土壤特异生物类群功能、土壤生物多样性以及土壤酶活性等也有不同程度的影响,且Bt蛋白有可能沿着食物链在人体内富集,对人体形成潜在的危害。因此,开展对Bt基因和Bt蛋白的监控研究是必要的,该文对Bt的相关研究现状作一简要综述。

  8. DEGRADATION OF Bt PROTEIN IN GROUND LEAVES AND BUDS FROM TRANSGENIC Bt COTTON%转Bt基因棉粉碎叶、蕾样Bt蛋白降解

    Institute of Scientific and Technical Information of China (English)

    张美俊; 杨武德

    2011-01-01

    以转Bt基因棉Bt冀668为材料,室内采用ELISA法,测定粉碎叶、蕾样Bt蛋白在土壤、水中不同时间的残留量以及不同环境处理下的残留量,以研究转Bt基因棉粉碎叶、蕾样Bt蛋白在不同基质中的降解动态以及与环境影响因子的关系.结果显示,粉碎叶、蕾样Bt蛋白分别在熟土、生土和水中前40d、48d取样天数间的残留量差异显著,中后期相邻两取样间无显著差异.取样结束时,熟土、生土和水中粉碎叶Bt蛋白残留量分别为初始量的7.4%、2.24%和15.48%,蕾样为初始量的6.22%、4.72%和15.71%,表明Bt蛋白在熟土、生土和水中前期快速降解,中后期进入缓慢稳定降解阶段,水中降解速率最慢,熟土中前期降解快于生土,后期降解反而慢于生土,使得其取样结束时残留量高于生土.75%含水量土壤中,粉碎叶Bt蛋白的降解显著快于25%和50%处理;35℃和25℃下降解显著快于15℃,5℃降解最慢;在有茵土中Bt蛋白的降解显著快于无菌土.上述结果显示一定范围内,高温、高湿可加快Bt蛋白的降解,且土壤微生物是促进Bt蛋白降解的重要因子之一.%The degradation dynamics of Bt protein in ground leaves and buds from transgenic Bt cotton in different substrates and their relation with environmental factors were investigated. Ground powers of BtJi 668 leaves and buds were mixed with soil or water, and residue Bt protein contents during sampling days (0 ~ 88days) and under different environment were determined by using enzyme-linked immunosorbent essay (ELISA) in laboratory. Residue Bt protein contents in ground leaves and buds had significant difference among sampling days at early stages, however, no difference between adjoining sampling days at middle and later stages in three substrates ripened soil, unripened soil and water. At the end of treated time, residue Bt protein contents in ground leaves decreased to 7.4% ,2. 24% and 15.48%, and in buds to

  9. Cry1Ab protein from Bt transgenic rice does not residue in rhizosphere soil

    International Nuclear Information System (INIS)

    Expression of Cry1Ab protein in Bt transgenic rice (KMD) and its residue in the rhizosphere soil during the whole growth in field, as well as degradation of the protein from KMD straw in five soils under laboratory incubation were studied. The residue of Cry1Ab protein in KMD rhizosphere soil was undetectable (below the limit of 0.5 ng/g air-dried soil). The Cry1Ab protein contents in the shoot and root of KMD were 3.23-8.22 and 0.68-0.89 μg/g (fresh weight), respectively. The half-lives of the Cry1Ab protein in the soils amended with KMD straw (4%, w/w) ranged from 11.5 to 34.3 d. The residence time of the protein varied significantly in a Fluvio-marine yellow loamy soil amended with KMD straw at the rate of 3, 4 and 7%, with half-lives of 9.9, 13.8 and 18 d, respectively. In addition, an extraction method for Cry1Ab protein in soil was developed, with extraction efficiencies of 46.4-82.3%. - Cry1Ab protein was not detected in the rhizosphere soil of field-grown Bt transgenic rice

  10. Efeitos de plantas Bt de soja e milho sobre pragas não-alvo e seus inimigos naturais

    OpenAIRE

    Silva, Gabriela Vieira

    2013-01-01

    Resumo: As plantas geneticamente modificadas resistentes a insetos (plantas Bt) tem apresentado eficiência no manejo de pragas em diversas culturas no mundo, mas ainda pouco se conhece sobre seus efeitos em organismos não-alvo (pragas e inimigos naturais). No Brasil, cultiva-se o milho Bt, entre eles o Herculex, que expressa a proteína Cry1F e o PowerCore, que expressa as proteínas Cry1F, Cry1A.105 e Cry2Ab2. A soja transgênica, que expressa a proteína Cry1Ac já foi liberada e em breve deve s...

  11. Larval development of Spodoptera eridania (Cramer) fed on leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 proteins and its non-Bt isoline

    OpenAIRE

    2015-01-01

    This study aimed to evaluate, in controlled laboratory conditions (temperature of 25±2 °C, relative humidity of 60±10%, and 14/10 h L/D photoperiod), the larval development of Spodoptera eridania (Cramer, 1784) (Lepidoptera, Noctuidae) fed with leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 insecticide proteins and its non-Bt isoline. Maize leaves triggered 100% of mortality on S. eridania larvae independently of being Bt or non-Bt plants. However, it was observed that in...

  12. Impacts of Bt rice expressing Cry1C or Cry2A protein on the performance of nontarget leafhopper, Nephotettix cincticeps (Hemiptera: Cicadellidae), under laboratory and field conditions.

    Science.gov (United States)

    Lu, Z B; Tian, J C; Wang, W; Xu, H X; Hu, C; Guo, Y Y; Peng, Y F; Ye, G Y

    2014-02-01

    Transgenic rice expressing Bacillus thuringiensis Berliner (Bt) protein can effectively control target insects including stem borers and leaf folders. However, the potential effects of Bt rice on nontarget organisms including nontarget herbivores have not been fully evaluated. In the current study, ecological fitness parameters of the nontarget herbivore, Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae), fed on T1C-19 (Cry1C) or T2A-1 (Cry2A) rice were compared with non-Bt rice (MH63) under laboratory conditions. A 2-yr field trial was also conducted to monitor the population dynamics of N. cincticeps in the Bt and control rice plots using the vacuum-suction machine and yellow sticky card traps. Laboratory results showed that there were no significant differences in some of biological parameters including egg developmental duration, adult fresh weight, adult longevity, and oviposition period when N. cincticeps fed on Bt or non-Bt rice was compared. However, the survival rate of N. cincticeps nymphs fed on T2A-1 Bt rice plants was significantly higher than that on the control. When N. cincticeps fed on T1C-19 Bt rice plants, its nymphal duration was significantly longer and fecundity significantly lower compared with those fed on both T2A-1 Bt and non-Bt rice plants; the preoviposition period of N. cincticeps fed on T1C-19 and T2A-1 Bt rice was also significantly shorter than those on non-Bt rice. Nonetheless, both seasonal density and population dynamics of N. cincticeps adults and nymphs were similar between Bt (T1C-19 and T2A-1) and non-Bt rice plots under field conditions. In conclusion, our results indicate that our two tested Bt rice lines would not lead to higher population of N. cincticeps. Long-term experiments to monitor the population dynamics of N. cincticeps at large scale need to be carried out to confirm the current results.

  13. Prediction on Antigenic Epitope Characteristics of Bt Cry2Ab Protein in Transgenic Crops

    Institute of Scientific and Technical Information of China (English)

    Jierong GAO; Ying HE; Zehong ZOU; Ailin TAO; Yuncan AI

    2012-01-01

    Abstract [Objective] This study aimed to predict the structural characteristics of Bt Cry2Ab protein in transgenic crops with bioinformatic analysis to provide the theoreti- cal clues for design of antibody Cry2Ab. [Method] The amino acid sequence of Cry2Ab protein was searched from NCBI database. The B cell epitopes were pre- dicted with DNAStar. The binding affinity between Cry2Ab protein and MHC-II molecules was analyzed with NetMHCII 2.2 Server to predict the T cell epitopes. [Result] Prediction result suggested the potential B cell epitope of Cry2Ab locating in the region of 208-215. Analysis of the binding affinity between Cry2Ab and MHC-II molecules suggested the regions of 177-185, 299-307 and 255-263 were the po- tential T cell epitopes. Human with HLA-DRB10101 alleles and HLA-DRB10701 al- leles were more sensitive to Cry2Ab protein. [Conclusion] This study facilitates to un- derstand the structural characteristics of Cry2Ab protein and provides a new clue to improve the assessment method for potential allergenicity of genetically modified food.

  14. Larval development of Spodoptera eridania (Cramer fed on leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 proteins and its non-Bt isoline

    Directory of Open Access Journals (Sweden)

    Orcial Ceolin Bortolotto

    2015-03-01

    Full Text Available This study aimed to evaluate, in controlled laboratory conditions (temperature of 25±2 °C, relative humidity of 60±10%, and 14/10 h L/D photoperiod, the larval development of Spodoptera eridania (Cramer, 1784 (Lepidoptera, Noctuidae fed with leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 insecticide proteins and its non-Bt isoline. Maize leaves triggered 100% of mortality on S. eridania larvae independently of being Bt or non-Bt plants. However, it was observed that in overall Bt maize (expressing a single or pyramided protein slightly affects the larval development of S. eridania, even under reduced leaf consumption. Therefore, these results showed that Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 can affect the larval development of S. eridania, although it is not a target pest of this plant; however, more research is needed to better understand this evidence. Finally, this study confirms that non-Bt maize leaves are unsuitable food source to S. eridania larvae, suggesting that they are not a potential pest in maize fields.

  15. Studies on Rapid Quantitative Analysis of Bt Toxin by Using Envirologix Kits in Transgenic Rice

    Institute of Scientific and Technical Information of China (English)

    XIE Xiao-bo; SHU Qing-yao

    2002-01-01

    Investigations were done on the usefulness of Envirologix Cry1Ab/Cry1Ac Plate kits for quantitative analysis of Bt toxin content in transgenic rice grains. Two transgenic rice lines: Kemingdao 1 (KMD1) and Kemingdao 2 (KMD2), transformed with a cry1Ab gene, and their parental variety, cv.Xiushui 11, were used as positive and negative samples. Results showed that the correlation coefficients as high as 0. 985 - 0. 998, significant at probability level of 0.05 or 0.01, were obtained for linear regression equations by using the appended calibrators of the kits. No significant differences were detected for values of same rice sample obtained from different trials or by using different lots of the product (kit). The detectable Bt toxin content by this method could be as low as 0.5 ng/g. The Envirologix Kit could be useful for rapid quantitative detection of Bt toxin in rice grains because of its preciseness, simplicity and time saving.

  16. Bacillus thuringiensis (Bt)

    Science.gov (United States)

    2004-01-01

    Bacillus thuringiensis (Bt), a natural bacteria found all over the Earth, has a fairly novel way of getting rid of unwanted insects. Bt forms a protein substance (shown on the right) that is not harmful to humans, birds, fish or other vertebrates. When eaten by insect larvae the protein causes a fatal loss of appetite. For over 25 years agricultural chemical companies have relied heavily upon safe Bt pesticides. New space based research promises to give the insecticide a new dimension in effectiveness and applicability. Researchers from the Consortium for Materials Development in Space along with industrial affiliates such as Abott Labs and Pern State University flew Bt on a Space Shuttle mission in the fall of 1996. Researchers expect that the Shuttle's microgravity environment will reveal new information about the protein that will make it more effective against a wider variety of pests.

  17. Study on Spatial-temporal Dynamics of Bt Toxic Protein Expression in Insect-resistant Transgenic Cotton and Its Degradation in Soil

    Institute of Scientific and Technical Information of China (English)

    Yiwen ZHANG; Lianrong WANG; Liancheng ZHANG; Jun ZHANG; Xinbo JI; Jinmao WANG

    2012-01-01

    [Ob.jcctive] This study aimed to investigate the spatial-temporal dynamics of Bt toxic protein expression in insect-resistant transgenic cotton and its degradation in soil. [Meth~d] BtcrylAc toxic protein expression in roots, stems and leaves of trans- genic cotton Guoshen GK45 at different developmental stages and the annual aver- age content of BtCrylAc toxin protein in the topsoil, rhizosphere soil and following cotton-growing area were explored and analyzed by using enzyme linked immuno sorbed assay (ELISA). [Result] The content of exogenous BtCrylAc toxin protein de- creased during the growth process of insect-resistant transgenic cotton; to be specif- ic, the content of BtCrylAc toxin protein in cotton stems and leaves decreased more slowly and always maintained a high level, while that in roots decreased rapidly and reached a minimum level to the following plant growth and development stage. BtCrylAc toxin protein was detected in topsoil of both non-transgenic and transgenic cotton-growing areas, and the content of BtCrylAc toxin protein increased in topsoil of following cotton-growing area, which was very low in rhizosphere soil. [Conclusion] Determination of BtcrylAc toxic protein provides scientific basis for the risk assess- ment of the cultivation of genetically modified crops and the safety evaluation of soil ecosystem.

  18. Toxicity of Bacillus thuringiensis (L.) Cry proteins against summer fruit tortrix (Adoxophyes orana - Fischer von Rösslerstamm).

    Science.gov (United States)

    Radosavljevic, Jelena; Naimov, Samir

    2016-07-01

    The activity of seven Cry1, one Cry9 and one hybrid Cry1 protoxins against neonate larvae of summer fruit tortrix (Adoxophyes orana - Fischer von Rösslerstamm) has been investigated. Cry1Ia is identified as the most toxic protein, followed by Cry1Aa and Cry1Ac. Cry1Ca, Cry1Cb, Cry1Da and Cry1Fa were less active, while SN19 (Cry1 hybrid protein with domain composition 1Ba/1Ia/1Ba) and Cry9Aa exhibited negligible toxicity against A. orana. In vitro trypsin-activated Cry1Ac is still less active than Cry1Ia protoxin, suggesting that toxicity of Cry1Ia is most probably due to more complex differences in further downstream processing, toxin-receptor interactions and pore formation in A. orana's midgut epithelium.

  19. Toxicity of Bacillus thuringiensis (L.) Cry proteins against summer fruit tortrix (Adoxophyes orana - Fischer von Rösslerstamm).

    Science.gov (United States)

    Radosavljevic, Jelena; Naimov, Samir

    2016-07-01

    The activity of seven Cry1, one Cry9 and one hybrid Cry1 protoxins against neonate larvae of summer fruit tortrix (Adoxophyes orana - Fischer von Rösslerstamm) has been investigated. Cry1Ia is identified as the most toxic protein, followed by Cry1Aa and Cry1Ac. Cry1Ca, Cry1Cb, Cry1Da and Cry1Fa were less active, while SN19 (Cry1 hybrid protein with domain composition 1Ba/1Ia/1Ba) and Cry9Aa exhibited negligible toxicity against A. orana. In vitro trypsin-activated Cry1Ac is still less active than Cry1Ia protoxin, suggesting that toxicity of Cry1Ia is most probably due to more complex differences in further downstream processing, toxin-receptor interactions and pore formation in A. orana's midgut epithelium. PMID:27311897

  20. Generation of insect-resistant and glyphosate-tolerant rice by introduction of a T-DNA containing two Bt insecticidal genes and an EPSPS gene.

    Science.gov (United States)

    Zhao, Qi-chao; Liu, Ming-hong; Zhang, Xian-wen; Lin, Chao-yang; Zhang, Qing; Shen, Zhi-cheng

    2015-10-01

    Insect resistance and glyphosate tolerance have been two of the most important traits in the genetic improvement of various crops. In this study, two Bacillus thuringiensis (Bt) insecticidal genes, Cry1Ac and Cry1Ig, and a modified glyphosate-tolerant 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene (G10) were combined into a single transferred DNA (T-DNA) fragment and introduced into rice by Agrobacterium-mediated transformation. A transgenic line with single-copy T-DNA insertion named GAI-14 was found to be highly resistant to striped stem borer and rice leaf roller, and tolerant to glyphosate. Analysis of T-DNA border sequence suggested that the transgenes were inserted at the chromosome 3 and appeared to have not interrupted any known or putative genes. A field trial observed no significant difference in the basic agronomic traits between GAI-14 and the recipient rice.

  1. The Cry1Ab Protein Has Minor Effects on the Arbuscular Mycorrhizal Fungal Communities after Five Seasons of Continuous Bt Maize Cultivation

    Science.gov (United States)

    Shu, Yinghua; Zhang, Yanyan; Feng, Yuanjiao; Wang, Jianwu

    2015-01-01

    The cultivation of genetically modified plants (GMP) has raised concerns regarding the plants’ ecological safety. A greenhouse experiment was conducted to assess the impact of five seasons of continuous Bt (Bacillus thuringiensis) maize cultivation on the colonisation and community structure of the non-target organisms arbuscular mycorrhizal fungi (AMF) in the maize roots, bulk soils and rhizospheric soils using the terminal restriction fragment length polymorphism (T-RFLP) analysis of the 28S ribosomal DNA and sequencing methods. AMF colonisation was significantly higher in the two Bt maize lines that express Cry1Ab, 5422Bt1 (event Bt11) and 5422CBCL (MON810) than in the non-Bt isoline 5422. No significant differences were observed in the diversity of the AMF community between the roots, bulk soils and rhizospheric soils of the Bt and non-Bt maize cultivars. The AMF genus Glomus was dominant in most of the samples, as detected by DNA sequencing. A clustering analysis based on the DNA sequence data suggested that the sample types (i.e., the samples from the roots, bulk soils or rhizospheric soils) might have greater influence on the AMF community phylotypes than the maize cultivars. This study indicated that the Cry1Ab protein has minor effects on the AMF communities after five seasons of continuous Bt maize cultivation. PMID:26717324

  2. The Cry1Ab Protein Has Minor Effects on the Arbuscular Mycorrhizal Fungal Communities after Five Seasons of Continuous Bt Maize Cultivation.

    Science.gov (United States)

    Zeng, Huilan; Tan, Fengxiao; Shu, Yinghua; Zhang, Yanyan; Feng, Yuanjiao; Wang, Jianwu

    2015-01-01

    The cultivation of genetically modified plants (GMP) has raised concerns regarding the plants' ecological safety. A greenhouse experiment was conducted to assess the impact of five seasons of continuous Bt (Bacillus thuringiensis) maize cultivation on the colonisation and community structure of the non-target organisms arbuscular mycorrhizal fungi (AMF) in the maize roots, bulk soils and rhizospheric soils using the terminal restriction fragment length polymorphism (T-RFLP) analysis of the 28S ribosomal DNA and sequencing methods. AMF colonisation was significantly higher in the two Bt maize lines that express Cry1Ab, 5422Bt1 (event Bt11) and 5422CBCL (MON810) than in the non-Bt isoline 5422. No significant differences were observed in the diversity of the AMF community between the roots, bulk soils and rhizospheric soils of the Bt and non-Bt maize cultivars. The AMF genus Glomus was dominant in most of the samples, as detected by DNA sequencing. A clustering analysis based on the DNA sequence data suggested that the sample types (i.e., the samples from the roots, bulk soils or rhizospheric soils) might have greater influence on the AMF community phylotypes than the maize cultivars. This study indicated that the Cry1Ab protein has minor effects on the AMF communities after five seasons of continuous Bt maize cultivation. PMID:26717324

  3. Isolation and Identification of Bacillus thuringensis (Bt) from Coalfields%煤矿中苏云金芽胞杆菌(Bt)菌株的分离及其鉴定

    Institute of Scientific and Technical Information of China (English)

    林白容; 章秋萍; 王毅斌; 关雄

    2014-01-01

    (2-DE/MS) showed that isolated Bt strain encoded approximately 130 kD crystal protein, which was then identified as insecticidal protein Cry1Ac by mass spectrometry (MALDI-TOF/TOF-MS). Molecular chaperone GroEL, ATP F0F1 synthase subunit beta, elongation factor Tu and pyruvate dehydrogenase were identified by MALDI-TOF/TOF-MS, respectively. Further understanding of protein functions were conducted through bioinformatics analysis, leading to correct folding of nascent peptides, energy production and conversion, as well as improving the ability of cells to withstand adverse external stimuli. This work provides basic data for discovering new Bt resources, new insecticidal protein and using microbial to control heavy metal pollution.

  4. Relationship Between Leaf C/N Ratio and Insecticidal Protein Expression in Bt Cotton as Affected by High Temperature and N Rate

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiang; LÜ Chun-hua; CHEN Yuan; WANG Gui-xia; CHEN Yuan; CHEN De-hua

    2014-01-01

    Expression of insecticidal protein for transgenic Bacillus thuringiensis (Bt) cotton is unstable and related to nitrogen metabolism. The objective of this study was to investigate the relationship between leaf carbon nitrogen ratio (C/N) and insecticidal efifcacy of two Bt cotton cultivars. C/N ratio and Bt protein content were both measured at peak square period and peak boll period respectively under 5-7 d high temperature and different nitrogen fertilizer rates on the Yangzhou University Farm and the Ludong Cotton Farm, China. All plants were grown in ifeld. The results showed that the C/N ratio enhanced slightly and the Bt protein content remained stable at peak square period, but significant increases for the C/N ratio and decreases markedly for the leaf Bt protein concentration were detected at the peak boll period. The similar patterns at the two growth periods were found for the leaf C/N ratio and Bt protein content by different N fertilizer treatments. When nitrogen rate was from 0 to 600 kg ha-1, the C/N ratio was reduced by 0.017 and 0.006 for Sikang 1 and Sikang 3 at peak square period, compared to the 1.350 to 1.143 reduction for Sikang 1 and Sikang 3 at peak boll period, respectively. Correspondingly, the leaf Bt protein contents were bolstered by 2.6-11.8 and 26.9-36.9% at the two different growth periods, respectively. The results suggested that enhanced C/N ratio by high temperature and nitrogen application may result in the reduction of insectiocidal efifcacy in Bt cotton, especially in peak boll period.

  5. Transfer of Bt-toxin protein gene into maize by high-velocity microprojectile bombardments and regeneration of transgenic plants

    Institute of Scientific and Technical Information of China (English)

    王国英; 杜天兵; 张宏; 谢友菊; 戴景瑞; 米景九; 李太源; 田颖川; 乔利亚; 莽克强

    1995-01-01

    Bt-toxin protein gene was successfully transferred into maize by the microprojectile bombard-ments of cell suspension,embryogenic calli and immature embryos with a Chinese-made particle gun(JQ-700).Although the bombarded embryogenic calli and immature embryos produced less mean transformants per dishthan the cell suspensions,they were the suitable materials for maize transformation because their culture andregeneration have been achieved in most maize cultivars.The evaluation on the resistance of transgenic plantsto corn borer shows the significant difference between them,from highly resistant to susceptible.

  6. Resistance to Bacillus thuringiensis Mediated by an ABC Transporter Mutation Increases Susceptibility to Toxins from Other Bacteria in an Invasive Insect

    Science.gov (United States)

    Zhang, Dandan; Gong, Lingling; He, Fei; Soberón, Mario; Bravo, Alejandra; Tabashnik, Bruce E.; Wu, Kongming

    2016-01-01

    Evolution of pest resistance reduces the efficacy of insecticidal proteins from the gram-positive bacterium Bacillus thuringiensis (Bt) used widely in sprays and transgenic crops. Recent efforts to delay pest adaptation to Bt crops focus primarily on combinations of two or more Bt toxins that kill the same pest, but this approach is often compromised because resistance to one Bt toxin causes cross-resistance to others. Thus, integration of Bt toxins with alternative controls that do not exhibit such cross-resistance is urgently needed. The ideal scenario of negative cross-resistance, where selection for resistance to a Bt toxin increases susceptibility to alternative controls, has been elusive. Here we discovered that selection of the global crop pest, Helicoverpa armigera, for >1000-fold resistance to Bt toxin Cry1Ac increased susceptibility to abamectin and spineotram, insecticides derived from the soil bacteria Streptomyces avermitilis and Saccharopolyspora spinosa, respectively. Resistance to Cry1Ac did not affect susceptibility to the cyclodiene, organophospate, or pyrethroid insecticides tested. Whereas previous work demonstrated that the resistance to Cry1Ac in the strain analyzed here is conferred by a mutation disrupting an ATP-binding cassette protein named ABCC2, the new results show that increased susceptibility to abamectin is genetically linked with the same mutation. Moreover, RNAi silencing of HaABCC2 not only decreased susceptibility to Cry1Ac, it also increased susceptibility to abamectin. The mutation disrupting ABCC2 reduced removal of abamectin in live larvae and in transfected Hi5 cells. The results imply that negative cross-resistance occurs because the wild type ABCC2 protein plays a key role in conferring susceptibility to Cry1Ac and in decreasing susceptibility to abamectin. The negative cross-resistance between a Bt toxin and other bacterial insecticides reported here may facilitate more sustainable pest control. PMID:26872031

  7. Bt proteins Cry1Ah and Cry2Ab do not affect cotton aphid Aphis gossypii and ladybeetle Propylea japonica.

    Science.gov (United States)

    Zhao, Yao; Zhang, Shuai; Luo, Jun-Yu; Wang, Chun-Yi; Lv, Li-Min; Wang, Xiao-Ping; Cui, Jin-Jie; Lei, Chao-Liang

    2016-01-01

    Plant varieties expressing the Bt (Bacillus thuringiensis) insecticidal proteins Cry1Ah and Cry2Ab have potential commercialization prospects in China. However, their potential effects on non-target arthropods (NTAs) remain uncharacterized. The cotton aphid Aphis gossypii is a worldwide pest that damages various important crops. The ladybeetle Propylea japonica is a common and abundant natural enemy in many cropping systems in East Asia. In the present study, the effects of Cry1Ah and Cry2Ab proteins on A. gossypii and P. japonica were assessed from three aspects. First, neither of the Cry proteins affected the growth or developmental characteristics of the two test insects. Second, the expression levels of the detoxification-related genes of the two test insects did not change significantly in either Cry protein treatment. Third, neither of the Cry proteins had a favourable effect on the expression of genes associated with the amino acid metabolism of A. gossypii and the nutrition utilization of P. japonica. In conclusion, the Cry1Ah and Cry2Ab proteins do not appear to affect the cotton aphid A. gossypii or the ladybeetle P. japonica. PMID:26829252

  8. Construction of a new plant expression vector containing two insect resistant genes and its expression in transgenic tobacco plants

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new plant expression vector (pBS29K-BA) containing two insect resistant genes, a synthetic chimeric gene BtS29K encoding the activated insecticidal protein Cry1Ac and a gene API-BA encoding the arrowhead (Sagittaria sagittifolia L.) proteinase inhibitor (API) A and B, is constructed. Transgenic tobacco plants expressing these two genes are obtained through Agrobacterium-mediated transformation of tobacco leaf discs. The average expression levels of Cry1Ac and API-BA proteins in transgenic plants are of 3.2 μg and 4.9 μg per gram fresh leaf respectively. The results of insecticidal assay of transgenic plants indicate that the pBS29K-BA transformed plants are more resistant to insect damage than the plants expressing the Cry1Ac gene or API-BA gene alone.

  9. Food safety knowledge on the Bt mutant protein Cry8Ka5 employed in the development of coleopteran-resistant transgenic cotton plants

    NARCIS (Netherlands)

    Felipe Farias, Davi; Peijnenburg, A.A.C.M.; Grossi-de-Sá, Maria F.; Carvalho, A.F.U.

    2015-01-01

    Insecticidal Cry proteins from Bacillus thuringiensis (Bt) have been exploited in the development of genetically modified (GM) crops for pest control. However, several pests are still difficult to control such as the coleopteran boll weevil Anthonomus grandis. By applying in vitro molecular evolutio

  10. Genetic transformation and expression of transgenic lines of Populus x euramericana with insect-resistance and salt-tolerance genes.

    Science.gov (United States)

    Yang, R L; Wang, A X; Zhang, J; Dong, Y; Yang, M S; Wang, J M

    2016-01-01

    We characterized new transgenic varieties of poplar with multiple insect-resistant and salt stress tolerant genes. Two insect-resistant Bacillus thuringiensis (Bt) genes, Cry1Ac and Cry3A, and a salt-tolerant gene, Betaine aldehyde dehydrogenase (BADH) were inserted into a vector, p209-Cry1Ac-Cry3A-BADH. The clone of Populus x euramericana was transformed by the vector using the Agrobacterium-mediated method. Three transgenic lines were assessed using genetic detection and resistance expression analysis. PCR revealed that exogenous genes Cry1Ac, Cry3A, BADH and selective marker gene NPTII were present in three transgenic lines. Quantitative real-time PCR (qPCR) showed significant differences in the transcriptional abundance of three exogenous genes in different lines. Results of assays for Bt toxic proteins showed that the Cry1Ac and Cry3A toxic protein content of each line was 12.83-26.32 and 2108.91-2724.79 ng/g, respectively. The Cry1Ac toxic protein content of different lines was significantly different; the Cry3A toxic protein content was about 100 times higher than that of the Cry1Ac toxic protein. The insect-resistance test revealed the mortality rate of transgenic lines to Hyphantria cunea L1 larvae varied by 42.2-66.7%, which was significantly higher than non-transgenic lines. The mortality rate of L1 and L2 Plagiodera versicolora larvae was 100%. The insecticidal effect of transgenic lines to P. versicolora larvae was higher than that to H. cunea larvae. NaCl stress tolerance of three transgenic lines under 3-6% NaCl concentration was significantly higher than that of non-transgenic lines. PMID:27173305

  11. Use of Bt-resistant caterpillars to assess the effect of Cry proteins on beneficial natural enemies

    Science.gov (United States)

    A concern related to the use of insect-resistant Bt-transgenic plants is their potential to harm non-target organisms, especially natural enemies of important crop pests. A few studies purporting to show negative effects of Bt plants on non-target organisms had tremendous negative effects on the per...

  12. Effect of Cry1Ab protein on rhizobacterial communities of Bt-maize over a four-year cultivation period.

    Directory of Open Access Journals (Sweden)

    Jorge Barriuso

    Full Text Available BACKGROUND: Bt-maize is a transgenic variety of maize expressing the Cry toxin from Bacillus turingiensis. The potential accumulation of the relative effect of the transgenic modification and the cry toxin on the rhizobacterial communities of Bt-maize has been monitored over a period of four years. METHODOLOGY/PRINCIPAL FINDINGS: The accumulative effects of the cultivation of this transgenic plant have been monitored by means of high throughput DNA pyrosequencing of the bacterial DNA coding for the 16S rRNA hypervariable V6 region from rhizobacterial communities. The obtained sequences were subjected to taxonomic, phylogenetic and taxonomic-independent diversity studies. The results obtained were consistent, indicating that variations detected in the rhizobacterial community structure were possibly due to climatic factors rather than to the presence of the Bt-gene. No variations were observed in the diversity estimates between non-Bt and Bt-maize. CONCLUSIONS/SIGNIFICANCE: The cultivation of Bt-maize during the four-year period did not change the maize rhizobacterial communities when compared to those of the non-Bt maize. This is the first study to be conducted with Bt-maize during such a long cultivation period and the first evaluation of rhizobacterial communities to be performed in this transgenic plant using Next Generation Sequencing.

  13. Cross-Resistance between Cry1 Proteins in Fall Armyworm (Spodoptera frugiperda May Affect the Durability of Current Pyramided Bt Maize Hybrids in Brazil.

    Directory of Open Access Journals (Sweden)

    Daniel Bernardi

    Full Text Available Genetically modified plants expressing insecticidal proteins from Bacillus thuringiensis (Bt offer valuable options for managing insect pests with considerable environmental and economic benefits. Despite the benefits provided by Bt crops, the continuous expression of these insecticidal proteins imposes strong selection for resistance in target pest populations. Bt maize (Zea mays hybrids have been successful in controlling fall armyworm (Spodoptera frugiperda, the main maize pest in Brazil since 2008; however, field-evolved resistance to the protein Cry1F has recently been reported. Therefore it is important to assess the possibility of cross-resistance between Cry1F and other Cry proteins expressed in Bt maize hybrids. In this study, an F2 screen followed by subsequent selection on MON 89034 maize was used to select an S. frugiperda strain (RR able to survive on the Bt maize event MON 89034, which expresses the Cry1A.105 and Cry2Ab2 proteins. Field-collected insects from maize expressing the Cry1F protein (event TC1507 represented most of the positive (resistance allele-containing (isofamilies found. The RR strain showed high levels of resistance to Cry1F, which apparently also conferred high levels of cross resistance to Cry1A.105 and Cry1Ab, but had only low-level (10-fold resistance to Cry2Ab2. Life history studies to investigate fitness costs associated with the resistance in RR strain revealed only small reductions in reproductive rate when compared to susceptible and heterozygous strains, but the RR strain produced 32.2% and 28.4% fewer females from each female relative to the SS and RS (pooled strains, respectively. Consistent with the lack of significant resistance to Cry2Ab2, MON 89034 maize in combination with appropriate management practices continues to provide effective control of S. frugiperda in Brazil. Nevertheless, the occurrence of Cry1F resistance in S. frugiperda across Brazil, and the cross-resistance to Cry1Ab and Cry1A

  14. Cross-Resistance between Cry1 Proteins in Fall Armyworm (Spodoptera frugiperda) May Affect the Durability of Current Pyramided Bt Maize Hybrids in Brazil.

    Science.gov (United States)

    Bernardi, Daniel; Salmeron, Eloisa; Horikoshi, Renato Jun; Bernardi, Oderlei; Dourado, Patrick Marques; Carvalho, Renato Assis; Martinelli, Samuel; Head, Graham P; Omoto, Celso

    2015-01-01

    Genetically modified plants expressing insecticidal proteins from Bacillus thuringiensis (Bt) offer valuable options for managing insect pests with considerable environmental and economic benefits. Despite the benefits provided by Bt crops, the continuous expression of these insecticidal proteins imposes strong selection for resistance in target pest populations. Bt maize (Zea mays) hybrids have been successful in controlling fall armyworm (Spodoptera frugiperda), the main maize pest in Brazil since 2008; however, field-evolved resistance to the protein Cry1F has recently been reported. Therefore it is important to assess the possibility of cross-resistance between Cry1F and other Cry proteins expressed in Bt maize hybrids. In this study, an F2 screen followed by subsequent selection on MON 89034 maize was used to select an S. frugiperda strain (RR) able to survive on the Bt maize event MON 89034, which expresses the Cry1A.105 and Cry2Ab2 proteins. Field-collected insects from maize expressing the Cry1F protein (event TC1507) represented most of the positive (resistance allele-containing) (iso)families found. The RR strain showed high levels of resistance to Cry1F, which apparently also conferred high levels of cross resistance to Cry1A.105 and Cry1Ab, but had only low-level (10-fold) resistance to Cry2Ab2. Life history studies to investigate fitness costs associated with the resistance in RR strain revealed only small reductions in reproductive rate when compared to susceptible and heterozygous strains, but the RR strain produced 32.2% and 28.4% fewer females from each female relative to the SS and RS (pooled) strains, respectively. Consistent with the lack of significant resistance to Cry2Ab2, MON 89034 maize in combination with appropriate management practices continues to provide effective control of S. frugiperda in Brazil. Nevertheless, the occurrence of Cry1F resistance in S. frugiperda across Brazil, and the cross-resistance to Cry1Ab and Cry1A.105

  15. Genetically modified rice Bt-Shanyou63 expressing Cry1Ab/c protein does not harm Daphnia magna.

    Science.gov (United States)

    Zhang, Li; Guo, Ruqing; Fang, Zhixiang; Liu, Biao

    2016-10-01

    The genetically modified (GM) rice Bt-ShanYou63 (Bt-SY63) received an official biosafety certificate while its safety remained in dispute. In a lifelong study, Daphnia magna were experimentally fed a basal diet of rice flours from Bt-SY63 or its parental rice ShanYou63 (SY63) at concentrations of 0.2mg, 0.3mg, or 0.4mgC (per individual per day). Overall the survival, body size, and reproduction of the animals were comparable between Bt-SY63 and ShanYou63.. The results showed that no significant differences were observed in growth and reproduction parameters between D. magna fed GM and non-GM flour and no dose-related changes occurred in all the values. Based on the different parameters assessed, the GM rice Bt-SY63 is a safe food source for D. magna that does not differ in quality from non-GM rice.

  16. Genetically modified rice Bt-Shanyou63 expressing Cry1Ab/c protein does not harm Daphnia magna.

    Science.gov (United States)

    Zhang, Li; Guo, Ruqing; Fang, Zhixiang; Liu, Biao

    2016-10-01

    The genetically modified (GM) rice Bt-ShanYou63 (Bt-SY63) received an official biosafety certificate while its safety remained in dispute. In a lifelong study, Daphnia magna were experimentally fed a basal diet of rice flours from Bt-SY63 or its parental rice ShanYou63 (SY63) at concentrations of 0.2mg, 0.3mg, or 0.4mgC (per individual per day). Overall the survival, body size, and reproduction of the animals were comparable between Bt-SY63 and ShanYou63.. The results showed that no significant differences were observed in growth and reproduction parameters between D. magna fed GM and non-GM flour and no dose-related changes occurred in all the values. Based on the different parameters assessed, the GM rice Bt-SY63 is a safe food source for D. magna that does not differ in quality from non-GM rice. PMID:27322607

  17. Impacts of Environmental Factors on Degradation of Cry1Ab Insecticidal Protein in Leaf-Blade Powders of Transgenic Bt Rice

    Institute of Scientific and Technical Information of China (English)

    BAI Yao-yu; JIANG Ming-xing; CHENG Jia-an

    2007-01-01

    The determination of the environmental fate of Bt insecticidal protein released by Bt rice plants in paddy soils is a key issue in its ecological risk assessment. In this study, the impacts of soil water content, pH, and temperature on the degradation of Cry1Ab protein expressed in the leaves of Bt rice KMD2 were studied in the laboratory. Three types of paddy soils were used, i.e., blue clayey paddy soil, pale paddy soil on quaternary red soil, and marine-fluvigenic yellow loamy paddy soil. Ground powders of KMD2 leaf blades were mixed with each type of soil, and degradation dynamics of Cry1Ab were measured using enzyme-linked immunosorbent assay (ELISA). The degradation rate of Cry1Ab was high at the early experimental stage, but slowed down steadily at middle and later stages, which could be described by exponential equations, with the half-life period of degradation determined as 1.8-4.0 d. The soil water content, pH, and temperature could affect the degradation of Cry1Ab, but the effects of soil pH and temperature were relatively greater. In general,Cry 1 Ab degradations were slower under lower soil pH and temperature conditions, especially for marine-fluvigenic yellow loamy paddy soil.

  18. Effects of insecticidal crystal proteins (Cry proteins) produced by genetically modified maize (Bt maize) on the nematode Caenorhabditis elegans

    International Nuclear Information System (INIS)

    The genetically modified maize MON89034 × MON88017 expresses different crystal (Cry) proteins with pesticidal activity against the European corn borer (Cry1.105; Cry2Ab2) and the Western corn root worm (Cry3Bb1). Non-target organisms, such as soil nematodes, might be exposed to the Cry proteins that enter the soil in course of crop growing. Therefore, the risk of those proteins for nematodes was assessed by testing their toxic effects on Caenorhabditis elegans. All three insecticidal Cry proteins showed dose-dependent inhibitory effects on C. elegans reproduction (EC50: 0.12–0.38 μmol L−1), however, at concentrations that were far above the expected soil concentrations. Moreover, a reduced toxicity was observed when Cry proteins were added jointly. A C. elegans mutant strain deficient for receptors for the nematicidal Cry5B was also resistant against Cry1.105 and Cry2Ab2, suggesting that these Cry proteins bound to the same or similar receptors as nematicidal Cry proteins and thereby affect the reproduction of C. elegans. -- Highlights: •Insecticidal Cry proteins dose-dependently inhibited the reproduction of C. elegans. •Mixture toxicity was lower than expected from concentration-additive single effects. •Genes for MAPK-defense-pathway were up-regulated in presence of Cry protein mixture. •Knock-out strains deficient for Cry5B-receptors showed lower susceptibility to insecticidal Cry proteins. •Toxicity of insecticidal Cry-proteins on C. elegans occurred at concentrations far above expected field concentrations. -- Insecticidal Cry proteins expressed by genetically modified maize act on nematodes via a similar mode of action as nematicidal Cry proteins, however, at concentrations far above expected soil levels

  19. Structure of Bacteroides thetaiotaomicron BT2081 at 2.05 Å resolution: the first structural representative of a new protein family that may play a role in carbohydrate metabolism

    International Nuclear Information System (INIS)

    The crystal structure of BT2081 from B. thetaiotaomicron reveals a two-domain protein with a putative carbohydrate-binding site in the C-terminal domain. BT2081 from Bacteroides thetaiotaomicron (GenBank accession code NP-810994.1) is a member of a novel protein family consisting of over 160 members, most of which are found in the different classes of Bacteroidetes. Genome-context analysis lends support to the involvement of this family in carbohydrate metabolism, which plays a key role in B. thetaiotaomicron as a predominant bacterial symbiont in the human distal gut microbiome. The crystal structure of BT2081 at 2.05 Å resolution represents the first structure from this new protein family. BT2081 consists of an N-terminal domain, which adopts a β-sandwich immunoglobulin-like fold, and a larger C-terminal domain with a β-sandwich jelly-roll fold. Structural analyses reveal that both domains are similar to those found in various carbohydrate-active enzymes. The C-terminal β-jelly-roll domain contains a potential carbohydrate-binding site that is highly conserved among BT2081 homologs and is situated in the same location as the carbohydrate-binding sites that are found in structurally similar glycoside hydrolases (GHs). However, in BT2081 this site is partially occluded by surrounding loops, which results in a deep solvent-accessible pocket rather than a shallower solvent-exposed cleft

  20. Identification of top-down forces regulating cotton aphid population growth in transgenic Bt cotton in central China.

    Directory of Open Access Journals (Sweden)

    Peng Han

    Full Text Available The cotton aphid Aphis gossypii Glover is the main aphid pest in cotton fields in the Yangtze River Valley Cotton-planting Zone (YRZ in central China. Various natural enemies may attack the cotton aphid in Bt cotton fields but no studies have identified potential specific top-down forces that could help manage this pest in the YRZ in China. In order to identify possibilities for managing the cotton aphid, we monitored cotton aphid population dynamics and identified the effect of natural enemies on cotton aphid population growth using various exclusion cages in transgenic Cry1Ac (Bt+CpTI (Cowpea trypsin inhibitor cotton field in 2011. The aphid population growth in the open field (control was significantly lower than those protected or restricted from exposure to natural enemies in the various exclusion cage types tested. The ladybird predator Propylaea japonica Thunberg represented 65% of Coccinellidae predators, and other predators consisted mainly of syrphids (2.1% and spiders (1.5%. The aphid parasitoids Aphidiines represented 76.7% of the total count of the natural enemy guild (mainly Lysiphlebia japonica Ashmead and Binodoxys indicus Subba Rao & Sharma. Our results showed that P. japonica can effectively delay the establishment and subsequent population growth of aphids during the cotton growing season. Aphidiines could also reduce aphid density although their impact may be shadowed by the presence of coccinellids in the open field (likely both owing to resource competition and intraguild predation. The implications of these results are discussed in a framework of the compatibility of transgenic crops and top-down forces exerted by natural enemy guild.

  1. 转Bt毒蛋白基因玉米及其抗虫性研究进展%Transgenic Corn with Bt Toxin Protein Gene and Insect-resistance

    Institute of Scientific and Technical Information of China (English)

    杨春英; 宋建成

    2001-01-01

    本文从转Bt毒蛋白基因玉米的培育及商品化,Bt毒蛋白基因在转基因玉米中的遗传分离与整合、对玉米螟及其它害虫的杀虫效果、对天敌种群数量和玉米病害发生程度的影响、玉米螟对转Bt毒蛋白基因玉米产生抗性及解决措施、应用转Bt毒蛋白基因玉米潜在的生态风险性等方面对国内外最新研究进展进行了综述。%This review briefly focused on the progress at home and overseas in the study of transgenic corn transformed with Bt toxic protein gene,including the breeding and commercial production of transgenic corn transformed with Bt toxic protein gene,genetic segregation and combination of Bt toxin protein in transgenic corn,insecticidal effect on corn borer and other pests,influence on natural enemy population amount and corn disease,corn borer tolerance to Bt toxic protein gene and countermeasures,and the potential ecological risk of transgenic corn transformed with Bt toxic protein gene.

  2. An Evaluation of Methods for Assessing the Impacts of Bt-maize on Non-target Organisms with Leafhoppers%利用叶蝉评价转基因玉米对非靶标生物的风险

    Institute of Scientific and Technical Information of China (English)

    冯艳杰; 葛阳; 谭树乾; 陈红星; 郭艳艳; 张恺祺; 石旺鹏

    2014-01-01

    The application of transgenic insect-resistant crops has been an important way to replace insecticides. But transgenic insect-resistant crops have potential negative effects, especially the effect on the non-target organisms and resistance to GM. Visual assessment and yellow traps were used for investigating the dynamic of leafhoppers and main arthropods in Cry1Ac transgenic insect-resistant corn field for two years. The study showed that planthoppers and leafhoppers were highly abundant and diverse in maize fields, their mid-term occurrence was 28.9%-43.1% of sucking pest insects, and the population dynamic had no significant difference between Bt-maize and the untreated near-isogenic maize. Leafhoppers were directly exposed to these entomotoxic proteins and could also serve as a source of Cry protein exposure to predatory arthropods. Therefore, it was reasonable to use Auchenorrhyncha in the risk assessment of GM corn. So the risk of Bt corn on non-target organisms could be evaluated using leafhoppers as an indicator species. The results in field tests showed that this method was feasible.%转基因抗虫作物应用是替代杀虫剂的重要途径。但转基因作物可能存负面效应,特别是对非靶标生物的影响及害虫产生抗性。采用直接和陷阱调查结合方法,连续多年对转Cry1Ac抗虫基因玉米实验田叶蝉和主要节肢动物数量动态跟踪调查,结果发现叶蝉是玉米田优势非靶标生物种群之一,中期发生比例占刺吸式害虫的28.9%~43.1%,且种群动态与主要非靶标节肢动物群落动态基本一致。又鉴于叶蝉直接刺吸接触到Bt杀虫蛋白,可直接反映转基因作物对非靶标生物的安全性,因此可利用叶蝉作为转基因抗虫玉米安全性评价指示生物来评价转基因玉米对非靶标生物群落风险,田间测试结果证明此方法是可行的。

  3. Spatio-temporal Expression of Foreign Bt Insecticidal Protein in Transgenic Bt Cotton Varieties in Northern Xinjiang Province, China%新疆北部地区转Bt基因棉外源杀虫蛋白表达时空动态研究

    Institute of Scientific and Technical Information of China (English)

    王冬梅; 李海强; 丁瑞丰; 汪飞; 李号宾; 徐遥; 阿克旦·吾外士; 刘建

    2012-01-01

    To study the spatial and temporal expression of Bt insecticidal protein in transgenic Bt cotton planted in northern Xinjiang Province, Bt insecticidal protein levels in four transgenic Bt cotton varieties (CCRI 43, GK62, GK19, sGK321), were quantitatively tested and compared during different developmental periods in 2009 and 2010, using the ELISA method. Trends in the spatio-temporal expression of Bt insecticidal protein were basically consistent between 2009 and 2010, although the expression amount was different, and some varieties had significant differentiation. Bt insecticidal protein levels varied with organs and developmental periods. The Bt insecticidal protein content gradually decreased with cotton development. The Bt insecticidal protein content of the cotyledon was the highest, and levels in the tender leaves during the cotyledon period, the three-leaf period, and the seven-leaf period were higher than those in the tender leaves, squares, petals and young bolls during the squaring period, flowering period, boiling period, respectivesly. Bt insecticidal protein levels in squares during the squaring period were higher than those in the flowering period and boiling period, and the levels in petals during the flowering period were higher than those during the boiling period. In the squaring period, the tender leaves had more Bt insecticidal protein than the squares; but in the flowering period, the squares had more Bt insecticidal protein than the tender leaves or the petals. In the boiling period, Bt insecticidal protein levels in tender leaves and squares were higher than those in petals and young bolls. The expression level of Bt in-secticidal protein in transgenic Bt cotton can thus be influenced by the kind of organ, the developmental period, variety, and planting season.%为研究新疆北部地区转Bt基因棉外源杀虫蛋白时空表达规律,2009年和2010年以中棉所43、GK62、 GK19和sGK321等4个转Bt基因抗虫棉为试验材料,利

  4. Improvement and efficient display of Bacillus thuringiensis toxins on M13 phages and ribosomes.

    Science.gov (United States)

    Pacheco, Sabino; Cantón, Emiliano; Zuñiga-Navarrete, Fernando; Pecorari, Frédéric; Bravo, Alejandra; Soberón, Mario

    2015-12-01

    Bacillus thuringiensis (Bt) produces insecticidal proteins that have been used worldwide in the control of insect-pests in crops and vectors of human diseases. However, different insect species are poorly controlled by the available Bt toxins or have evolved resistance to these toxins. Evolution of Bt toxicity could provide novel toxins to control insect pests. To this aim, efficient display systems to select toxins with increased binding to insect membranes or midgut proteins involved in toxicity are likely to be helpful. Here we describe two display systems, phage display and ribosome display, that allow the efficient display of two non-structurally related Bt toxins, Cry1Ac and Cyt1Aa. Improved display of Cry1Ac and Cyt1Aa on M13 phages was achieved by changing the commonly used peptide leader sequence of the coat pIII-fusion protein, that relies on the Sec translocation pathway, for a peptide leader sequence that relies on the signal recognition particle pathway (SRP) and by using a modified M13 helper phage (Phaberge) that has an amber mutation in its pIII genomic sequence and preferentially assembles using the pIII-fusion protein. Also, both Cry1Ac and Cyt1Aa were efficiently displayed on ribosomes, which could allow the construction of large libraries of variants. Furthermore, Cry1Ac or Cyt1Aa displayed on M13 phages or ribosomes were specifically selected from a mixture of both toxins depending on which antigen was immobilized for binding selection. These improved systems may allow the selection of Cry toxin variants with improved insecticidal activities that could counter insect resistances. PMID:26606918

  5. IT-BT convergence technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-12-15

    This book explains IT-BT convergence technology as the future technology, which includes a prolog, easy IT-BT convergence technology that has infinite potentials for new value, policy of IT-BT convergence technology showing the potential of smart Korea, IT-BT convergence opening happy future, for the new future of IT powerful nation Korea with IT-BT convergence technology and an epilogue. This book reveals the conception, policy, performance and future of IT-BT convergence technology.

  6. Current situation of pests targeted by Bt crops in Latin America.

    Science.gov (United States)

    Blanco, C A; Chiaravalle, W; Dalla-Rizza, M; Farias, J R; García-Degano, M F; Gastaminza, G; Mota-Sánchez, D; Murúa, M G; Omoto, C; Pieralisi, B K; Rodríguez, J; Rodríguez-Maciel, J C; Terán-Santofimio, H; Terán-Vargas, A P; Valencia, S J; Willink, E

    2016-06-01

    Transgenic crops producing Bacillus thuringiensis- (Bt) insecticidal proteins (Bt crops) have provided useful pest management tools to growers for the past 20 years. Planting Bt crops has reduced the use of synthetic insecticides on cotton, maize and soybean fields in 11 countries throughout Latin America. One of the threats that could jeopardize the sustainability of Bt crops is the development of resistance by targeted pests. Governments of many countries require vigilance in measuring changes in Bt-susceptibility in order to proactively implement corrective measures before Bt-resistance is widespread, thus prolonging the usefulness of Bt crops. A pragmatic approach to obtain information on the effectiveness of Bt-crops is directly asking growers, crop consultants and academics about Bt-resistance problems in agricultural fields, first-hand information that not necessarily relies on susceptibility screens performed in laboratories. This type of information is presented in this report. Problematic pests of cotton and soybeans in five Latin American countries currently are effectively controlled by Bt crops. Growers that plant conventional (non-Bt) cotton or soybeans have to spray synthetic insecticides against multiple pests that otherwise are controlled by these Bt crops. A similar situation has been observed in six Latin American countries where Bt maize is planted. No synthetic insecticide applications are used to control corn pests because they are controlled by Bt maize, with the exception of Spodoptera frugiperda. While this insect in some countries is still effectively controlled by Bt maize, in others resistance has evolved and necessitates supplemental insecticide applications and/or the use of Bt maize cultivars that express multiple Bt proteins. Partial control of S. frugiperda in certain countries is due to its natural tolerance to the Bt bacterium. Of the 31 pests targeted and controlled by Bt crops in Latin America, only S. frugiperda has shown

  7. Screening of Bt isolates with insecticidal activity against Apolygus lucorum (Heteroptera:Miridae)and bioassay of Cry15Aa polypeptides%对绿盲蝽具有杀虫活性Bt菌株的筛选及Cry15Aa蛋白活性的研究

    Institute of Scientific and Technical Information of China (English)

    张学雯; 束长龙; 陆宴辉; 刘春颖; 张杰; 高继国

    2016-01-01

    Transgenic cotton with cry genes has controlled the main cotton pests (Helicoverpa armigera )effective-ly,however another non target mirid bugs (Heteroptera:Miridae)with sucking mouthparts have increased popu-lation sizes year by year.It has not been reported to the effective insecticidal genes of Bacillus thuringiensis a-gainst Apolygus lucorum (Meyer-Dür),in this study,Bt insecticidal genes and isolates stored in our laboratory were prepared to assay the insecticidal activity against A.lucorum .The cry 15Aa gene which belongs to Mtx in our lab was used to perform the bioassay to A.lucorum ,the result showed that Cry15Aa polypeptides was certain insecticidal activity against A.lucorum .After bioassay against A.lucorum ,twenty A.lucorum toxic Bt isolates were obtained.The LC-MS/MS identification showed these isolates might contains Cry1Aa,Cry1Ab,Cry1Ac, Cry1Ae,Cry1Af,Cry1Ag,Cry1Ah,Cry1Ba,Cry1Be,Cry8Ha and other proteins which are insecticidal to lepi-doptera and coleopteran pests,and four of them contains peptide fragment similar to Cry15Aa which belong to Mtx protein.But subsequence gene identification results indicated that these isolates not contains full length cry 15Aa gene,it suggested that these isolates contains new cry 15 type genes.The results indicated that these Bt i-solates may contain new insecticidal proteins toxic to mirid bugs.The obtaining of novel Bt isolates and the discovery of Cry15Aa with insecticidal activity against A.lucorum are significant to the biological control for A.lucorum .%Bt 棉有效控制了棉田主要害虫棉铃虫(Helicoverpa armigera ),然而原来处于次要地位的刺吸式口器害虫盲蝽(Heteroptera:Miridae)为害逐年加重,目前对绿盲蝽(Apolygus lucorum Meyer-Dür)有效的抗虫基因未见报道。本研究以本实验室保存的 Bt 杀虫基因和菌株为材料,对绿盲蝽进行杀虫活性筛选。利用本实验室先前克隆的Mtx 类杀虫基因 cry15Aa 表达产物进行绿

  8. Food safety knowledge on the Bt mutant protein Cry8Ka5 employed in the development of coleopteran-resistant transgenic cotton plants.

    Science.gov (United States)

    Farias, Davi F; Peijnenburg, Ad A C M; Grossi-de-Sá, Maria F; Carvalho, Ana F U

    2015-01-01

    Insecticidal Cry proteins from Bacillus thuringiensis (Bt) have been exploited in the development of genetically modified (GM) crops for pest control. However, several pests are still difficult to control such as the coleopteran boll weevil Anthonomus grandis. By applying in vitro molecular evolution to the cry8Ka1 gene sequence, variants were generated with improved activity against A. grandis. Among them, Cry8Ka5 mutant protein showed coleoptericidal activity 3-fold higher (LC50 2.83 μg/mL) than that of the original protein (Cry8Ka1). Cry8Ka5 has been used in breeding programs in order to obtain coleopteran-resistant cotton plants. Nevertheless, there is some concern in relation to the food safety of transgenic crops, especially to the heterologously expressed proteins. In this context, our research group has performed risk assessment studies on Cry8Ka5, using the tests recommended by Codex as well as tests that we proposed as alternative and/or complementary approaches. Our results on the risk analysis of Cry8Ka5 taken together with those of other Cry proteins, point out that there is a high degree of certainty on their food safety. It is reasonable to emphasize that most safety studies on Cry proteins have essentially used the Codex approach. However, other methodologies would potentially provide additional information such as studies on the effects of Cry proteins and derived peptides on the indigenous gastrointestinal microbiota and on intestinal epithelial cells of humans. Additionally, emerging technologies such as toxicogenomics potentially will offer sensitive alternatives for some current approaches or methods.

  9. Bt Toxin Modification for Enhanced Efficacy

    Directory of Open Access Journals (Sweden)

    Benjamin R. Deist

    2014-10-01

    Full Text Available Insect-specific toxins derived from Bacillus thuringiensis (Bt provide a valuable resource for pest suppression. Here we review the different strategies that have been employed to enhance toxicity against specific target species including those that have evolved resistance to Bt, or to modify the host range of Bt crystal (Cry and cytolytic (Cyt toxins. These strategies include toxin truncation, modification of protease cleavage sites, domain swapping, site-directed mutagenesis, peptide addition, and phage display screens for mutated toxins with enhanced activity. Toxin optimization provides a useful approach to extend the utility of these proteins for suppression of pests that exhibit low susceptibility to native Bt toxins, and to overcome field resistance.

  10. 转基因抗虫耐除草剂(Cry1Ac+EPSPS)玉米对草甘膦耐受性研究%Tolerance of transgenic and herbicide-and insect-resistant corn to glyphosate

    Institute of Scientific and Technical Information of China (English)

    江帆; 刘凯强; 张天涛; 白树雄; 王振营; 何康来

    2016-01-01

    Insect-resistant cry 1Ac gene and glyphosate-tolerant gene were used to construct an insect-resistant/glyphosate-tolerant bivalent plant which had been patented.It effectively improved complex traits in corn.This study mainly evaluated the tolerance of insect-resistant/glyphosate-tolerant bivalent corn and glyphosate-tolerant corn to glyphosate,and measured the quantity of Cry1Ac and CP4 EPSPS protein expressed in corn tissues,in or-der to provide the basis for the improvement and application of the maize varieties.Insect-resistant/glyphosate-tolerant bivalent corn ‘CC-2×BT799’,insect-resistant corn ‘BT799’,herbicide-resistant corn ‘CC-2’,and con-ventional corn ‘Zheng 58’were compared by investigating the survival rates and heights of plants after spraying herbicides.Cry1Ac and CP4 EPSPS protein expression was measured by ELISA.‘CC-2’and ‘CC-2×BT799’per-formed excellent tolerance to glyphosate after spraying glyphosate with recommended and double recommended rates at the whorl stage.ELISA detection showed that CP4 EPSPS protein expression in the tassel was slightly higher than in leaves.CP4 EPSPS protein expression in ‘CC-2 ×BT799’was slightly higher than in ‘CC-2’. Cry1Ac protein expression in BT799 and ‘CC-2×BT799’was nearly the same in the tassel.However,Cry1Ac protein expression in BT799 leaves was about 2 times of that in ‘CC-2×BT799’.Insect-resistant/glyphosate-tolerant corn showed strong resistance to glyphosate.Cry1Ac protein expression varied among the corn varieties and tissues.%将具有我国自主知识产权的抗虫、耐除草剂基因转化到玉米中获得兼具抗虫和耐除草剂的复合性状转基因玉米,实现了玉米复杂性状的有效改良,研究了转耐除草剂 CC-2基因和可表达 Bt 毒素的 cry1Ac 基因的双抗玉米对除草剂的耐受性及目标蛋白表达量。通过调查喷施除草剂后玉米植株存活率及株高和生长发育情况,研究了转抗虫

  11. Advances in effects of insecticidal crystal proteins released from transgenic Bt crops on soil ecology%转Bt基因作物释放杀虫晶体蛋白对土壤生态安全的影响

    Institute of Scientific and Technical Information of China (English)

    周学永; 刘宁; 赵曼; 李河; 周浪; 唐宗文; 曹斐; 李巍

    2011-01-01

    With the large scale cultivation of transgenic crops expressing Bacillus thuringiensi.s (Bt) insecticidal crystal proteins in the world, the problem of environmental safety caused by these Bt crops has received extensive attention.These insecticidal crystal proteins can be released into the soil continuously in the growing period of Bt plants.If their accumulation of the insecticidal crystal proteins exceeds consumption by insect larvae and degradation by the environmental factors,these insecticidal crystal proteins could constitute a hazard to non-target insects and soil microbiota.There are three main ways to release insecticidal crystal proteins into soil for Bt plants: root exudates, pollen falling, and crop reside retuming.The Bt insecticidal crystal proteins released into soil can be adsorbed rapidly by active soil particles and the absorption equilibrium attained within l-3 h.The adsorption protects Bt insecticidal crystal proteins against soil microbial degradation or enzyme degradation, which leads to remarkable prolong of the persistence of insecticidal activity.The change of soil microorganism species is an important index for evaluating the effect of Bt plants on soil ecology.The research showed that these insecticidal crystal proteins released by the Bt plant root exudates or Bt organism had no toxicity to the soil earthworms, nematodes, protozoa, bacteria and fungi; however, it could reduce the mycelium length of the arbuscular mycorrhizal fungi (AMF) and restrain AMF to form mvasion unit.The influencing degree of Bt protein on soil enzyme activity varied with the releasing modes or growth period of Bt crops.Bt CryIAb protein can be taken up from soil by parts of following crops; however, different results were obtained with different commercial kits.To better understand the soil ecological evaluation about the insecticidal crystal proteins released from transgenic Bt crops, this review provides a comprehensive overview about the release, adsorption

  12. 转Bt基因玉米叶片中Bt蛋白的表达和分泌研究%Study on Expression and Exudation of Bt Protein in Leaves of Transgenic Insect- resistant Corn

    Institute of Scientific and Technical Information of China (English)

    田晓燕; 赵蕾; 孙红炜; 李凡; 赵辉; 颜世磊; 路兴波

    2012-01-01

    With the transgenic insect - resistant corn Mon810 and its non - transgenic parent as materials , the enzyme - linked immunosorbent assay (ELISA ) method was used to detect the expression and quanti-tate the exudation of Bt protein in corn leaves. The results showed that Bt protein could be detected in tissue and on surface of leaves. The Bt content in tissues showed a rising trend from seedling stage to silking stage with the advances of vegetable growth, and reached the peak at the silking stage and then declined gradually. The variation of Bt exudation on leaf surface had no obvious regularity.%以转Bt玉米Mon810及其亲本非转基因玉米为研究对象,通过酶联免疫吸附测定法(ELISA)定量检测Mon810玉米叶中Bt蛋白表达量和叶表Bt蛋白分泌量,结果表明叶组织和叶表均可检测到Bt蛋白,组织内Bt蛋白量从苗期到抽丝期随着植株营养生长的加快呈上升趋势,至抽丝期达到顶峰,之后逐渐降低;叶表Bt蛋白分泌量变化无明显规律性.

  13. The Binding Characterization of Cry Insecticidal Proteins to the Brush Border Membrane Vesicles of Helicoverpa armigera, Spodoptera exigua, Spodoptera litura and Agrotis ipsilon

    Institute of Scientific and Technical Information of China (English)

    LU Qiong; CAO Guang-chun; ZHANG Li-li; LIANG Ge-mei; GAO Xi-wu; ZHANG Yong-jun; GUO Yu-yuan

    2013-01-01

    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 Cry1Ac>Cry1Ab>Cry2Ab for Helicoverpa armigera, Cry1B>Cry1C>Cry2Ab for Spodoptera exigua, and Cry2Ab>Cry1B>Cry1C for S. litura. Only Cry2Ab was toxic to Agrotis ipsilon. Binding experiments were performed with 125I-Cry1Ab, 125I-Cry1Ac, 125I-Cry1B, 125I-Cry1C, 125I-Cry2Ab and the brush border membranes vesicles (BBMV) from H. armigera, S. exigua, S. litura and A. ipsilon. The binding of Cry1Ab and Cry1Ac 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±1.79) ng and (55.44±0.91) ng, separately). The binding of Cry1B was shown to be saturable by incubating with increasing concentrations of S. 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, Cry1B and Cry1C showed some combination with the BBMV of S. litura, and a certain amount of Cry2Ab could bind to the BBMV of A. 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.

  14. Can pyramids and seed mixtures delay resistance to Bt crops?

    Science.gov (United States)

    The primary strategy for delaying evolution of pest resistance to transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) entails refuges of plants that do not produce Bt toxins and thus allow survival of susceptible pests. Recent advances include using refuges together...

  15. DECOMPOSITION OF BT COTTON AND NON BT COTTON RESIDUES UNDER VARIED SOIL TYPES

    Directory of Open Access Journals (Sweden)

    Sujata Kumari

    2014-04-01

    Full Text Available Use of the insecticidal cry proteins from the bacterium, Bacillus thuringiensis (Bt in cotton has raised a number of concerns, including the ecological impact on soil ecosystems.Greenhouse study was conducted during the 2011 wet season (March to August at the Institute of Agricultural Sciences of Banaras Hindu University. It was carried out on three different soil orders that includedentisol, inceptisol and alfisol. Bt cotton (var.NCS-138 and its non-transgenic isoline (var.NCS-138 were grown until maturity. A no crop pot was maintained for all the three soil orders. The highest rate of decomposition was found in alluvial soil compared to black and red soils in 50 days after incorporation (DAI. Thereafter the rate of decomposition was slowed downby100 DAI and the constant rate of decomposition was found in 150 DAI. The rate of decomposition was higher in non Bt than Bt crop residues.

  16. Breeding of Trans-Bt Gene Rice Varieties with Pest Resistance by Means of Marker-Assisted Selection (MAS)%利用分子标记辅助选择培育转 Bt基因抗虫水稻

    Institute of Scientific and Technical Information of China (English)

    张琳; 魏志刚; 裴婷婷; 胡颂平; 余霞; 张静; 罗利军; 叶水峰; 刘国兰

    2014-01-01

    In order to breed trans-Bt gene rice materials with pest resistance,three Bt genes,cry1Ac/Ab, cry1C* and cry2A*,from the donor parents developed by Huazhong Agricultural University were introgressed into Xiushui123,Xiangqing,Hanhui No.3 and Huhan1B,namely Minghui63( Cry1C*) ,Minghui63( Cry2A*) and Minghui63 ( Cry1Ab/Ac) respectively using the method of traditional hybrid;then the new type lines of trans-Bt gene rice were by obtained means of maker-assisted selection ( MAS) ,screening of basta test in the field and test paper strip detection.In addition trans-gene rice lines of good pest resistance and fine agricultural traits were scteened by using the assays of insect-resistance in the field under normal field management but without spraying pesticide in the whole bearing stage of these trans-gene lines providing the materials for fur-ther anti-pest breeding.The homozygous lines with cry1C* and cry2A were obtained in the different back-grounds ( Xiushui123,Xiangqing and Huhan1B) respectively by the detection of PCR and test paper strip.At the same time,Bt lines showed excellent resistance to rice leaf roller in the field under the condition of its natu-ral occurrence.%为培育转Bt基因抗虫水稻品种材料,以传统杂交的方法将3个Bt明恢63中的Bt基因cry1C*、cry2A*和cry1Ac/Ab,转育到水稻品种秀水123、湘晴、旱恢3号和沪旱1B中;以回交二代自交三代(BC2F3)水稻叶片为材料,利用分子标记辅助选择、田间除草剂筛选和试纸条检测方法,以获得新型转Bt基因株系。并在全生育期实行除不喷施农药外的正常田间管理的转基因植株的田间抗虫鉴定方法筛选出抗虫性良好、农艺性状优良的株系,为后续抗虫育种提供材料。 BC2 F3代PCR检测及试纸条检测的结果显示分别获得cry1C*和cry2A*基因的沪旱1B、秀水123和湘晴的纯合株系。同时,在田间自然诱发虫害条件下,转基因株系对稻纵卷叶螟虫表现出强抗性。

  17. E.QUALITY@BT...

    Science.gov (United States)

    Macmillan, Roderick H.

    1996-01-01

    Describes a management system developed by BT Laboratories (United Kingdom) that is based on ISO 9001 using the World Wide Web, a hypermedia system, and part of the Internet. Subject matter is presented as an alphabetical list of linked entries, numerous navigational techniques are available, and searching options function within an index file.…

  18. Quality of laboratory studies assessing effects of Bt-proteins on non-target organisms: minimal criteria for acceptability.

    Science.gov (United States)

    De Schrijver, Adinda; Devos, Yann; De Clercq, Patrick; Gathmann, Achim; Romeis, Jörg

    2016-08-01

    The potential risks that genetically modified plants may pose to non-target organisms and the ecosystem services they contribute to are assessed as part of pre-market risk assessments. This paper reviews the early tier studies testing the hypothesis whether exposure to plant-produced Cry34/35Ab1 proteins as a result of cultivation of maize 59122 is harmful to valued non-target organisms, in particular Arthropoda and Annelida. The available studies were assessed for their scientific quality by considering a set of criteria determining their relevance and reliability. As a case-study, this exercise revealed that when not all quality criteria are met, weighing the robustness of the study and its relevance for risk assessment is not obvious. Applying a worst-case expected environmental concentration of bioactive toxins equivalent to that present in the transgenic crop, confirming exposure of the test species to the test substance, and the use of a negative control were identified as minimum criteria to be met to guarantee sufficiently reliable data. This exercise stresses the importance of conducting studies meeting certain quality standards as this minimises the probability of erroneous or inconclusive results and increases confidence in the results and adds certainty to the conclusions drawn. PMID:26980555

  19. Quality of laboratory studies assessing effects of Bt-proteins on non-target organisms: minimal criteria for acceptability.

    Science.gov (United States)

    De Schrijver, Adinda; Devos, Yann; De Clercq, Patrick; Gathmann, Achim; Romeis, Jörg

    2016-08-01

    The potential risks that genetically modified plants may pose to non-target organisms and the ecosystem services they contribute to are assessed as part of pre-market risk assessments. This paper reviews the early tier studies testing the hypothesis whether exposure to plant-produced Cry34/35Ab1 proteins as a result of cultivation of maize 59122 is harmful to valued non-target organisms, in particular Arthropoda and Annelida. The available studies were assessed for their scientific quality by considering a set of criteria determining their relevance and reliability. As a case-study, this exercise revealed that when not all quality criteria are met, weighing the robustness of the study and its relevance for risk assessment is not obvious. Applying a worst-case expected environmental concentration of bioactive toxins equivalent to that present in the transgenic crop, confirming exposure of the test species to the test substance, and the use of a negative control were identified as minimum criteria to be met to guarantee sufficiently reliable data. This exercise stresses the importance of conducting studies meeting certain quality standards as this minimises the probability of erroneous or inconclusive results and increases confidence in the results and adds certainty to the conclusions drawn.

  20. Green algae (Chlorella pyrenoidosa) adsorbs Bacillus thurigiensis (Bt) toxin, Cry1Ca insecticidal protein, without an effect on growth.

    Science.gov (United States)

    Wang, Jiamei; Chen, Xiuping; Li, Yunhe; Su, Changqing; Ding, Jiatong; Peng, Yufa

    2014-08-01

    The effect of purified Cry1Ca insecticidal protein on the growth of Chlorella pyrenoidosa was studied in a three-generation toxicity test. The C. pyrenoidosa medium with a density of 5.4 × 10(5) cells/mL was subcultured for three generations with added Cry1Ca at 0, 10, 100, and 1000 µg/L, and cell numbers were determined daily. To explore the distribution of Cry1Ca in C. pyrenoidosa and the culture medium, Cry1Ca was added at 1000 µg/L to algae with a high density of 4.8 × 10(6) cells/mL, and Cry1Ca content was determined daily in C. pyrenoidosa and the culture medium by enzyme-linked immunosorbent assays. Our results showed that the growth curves of C. pyrenoidosa exposed to 10, 100, and 1000 µg/L of Cry1Ca almost overlapped with that of the blank control, and there were no statistically significant differences among the four treatments from day 0 to day 7, regardless of generation. Moreover, the Cry1Ca content in the culture medium and in C. pyrenoidosa sharply decreased under exposure of 1000 µg/L Cry1Ca with high initial C. pyrenoidosa cell density. The above results demonstrate that Cry1Ca in water can be rapidly adsorbed and degraded by C. pyrenoidosa, but it has no suppressive or stimulative effect on algae growth.

  1. [Effects of transgenic Bt crops on non-target soil animals].

    Science.gov (United States)

    Yuan, Yi-gang; Ge, Feng

    2010-05-01

    Transgenic Bt crops are widely planted around the world. With the quick development and extension of genetically modified crops, it is needed to make a deep study on the effects of Bt crops on soil ecosystem. This paper reviewed the research progress on the effects of transgenic Bt crops on the population dynamics and community structure of soil animals, e.g., earthworm, nematode, springtail, mite, and beetle, etc. The development history of Bt crops was introduced, the passway the Bt protein comes into soil as well as the residual and degradation of Bt protein in soil were analyzed, and the critical research fields about the ecological risk analysis of transgenic Bt crops on non-target soil animals in the future were approached, which would provide a reference for the research of the effects of transgenic Bt crops on non-target soil animals.

  2. [Effects of transgenic Bt crops on non-target soil animals].

    Science.gov (United States)

    Yuan, Yi-gang; Ge, Feng

    2010-05-01

    Transgenic Bt crops are widely planted around the world. With the quick development and extension of genetically modified crops, it is needed to make a deep study on the effects of Bt crops on soil ecosystem. This paper reviewed the research progress on the effects of transgenic Bt crops on the population dynamics and community structure of soil animals, e.g., earthworm, nematode, springtail, mite, and beetle, etc. The development history of Bt crops was introduced, the passway the Bt protein comes into soil as well as the residual and degradation of Bt protein in soil were analyzed, and the critical research fields about the ecological risk analysis of transgenic Bt crops on non-target soil animals in the future were approached, which would provide a reference for the research of the effects of transgenic Bt crops on non-target soil animals. PMID:20707123

  3. Development of Bt Rice and Bt Maize in China and Their Efficacy in Target Pest Control

    Directory of Open Access Journals (Sweden)

    Qingsong Liu

    2016-10-01

    Full Text Available Rice and maize are important cereal crops that serve as staple foods, feed, and industrial material in China. Multiple factors constrain the production of both crops, among which insect pests are an important one. Lepidopteran pests cause enormous yield losses for the crops annually. In order to control these pests, China plays an active role in development and application of genetic engineering (GE to crops, and dozens of GE rice and GE maize lines expressing insecticidal proteins from the soil bacterium Bacillus thuringiensis (Bt have been developed. Many lines have entered environmental release, field testing, and preproduction testing, and laboratory and field experiments have shown that most of the Bt rice and Bt maize lines developed in China exhibited effective control of major target lepidopteran pests on rice (Chilo suppressalis, Scirpophaga incertulas, and Cnaphalocrocis medinalis and maize (Ostrinia furnacalis, demonstrating bright prospects for application. However, none of these Bt lines has yet been commercially planted through this writing in 2016. Challenges and perspectives for development and application of Bt rice and maize in China are discussed. This article provides a general context for colleagues to learn about research and development of Bt crops in China, and may shed light on future work in this field.

  4. Development of Bt Rice and Bt Maize in China and Their Efficacy in Target Pest Control

    Science.gov (United States)

    Liu, Qingsong; Hallerman, Eric; Peng, Yufa; Li, Yunhe

    2016-01-01

    Rice and maize are important cereal crops that serve as staple foods, feed, and industrial material in China. Multiple factors constrain the production of both crops, among which insect pests are an important one. Lepidopteran pests cause enormous yield losses for the crops annually. In order to control these pests, China plays an active role in development and application of genetic engineering (GE) to crops, and dozens of GE rice and GE maize lines expressing insecticidal proteins from the soil bacterium Bacillus thuringiensis (Bt) have been developed. Many lines have entered environmental release, field testing, and preproduction testing, and laboratory and field experiments have shown that most of the Bt rice and Bt maize lines developed in China exhibited effective control of major target lepidopteran pests on rice (Chilo suppressalis, Scirpophaga incertulas, and Cnaphalocrocis medinalis) and maize (Ostrinia furnacalis), demonstrating bright prospects for application. However, none of these Bt lines has yet been commercially planted through this writing in 2016. Challenges and perspectives for development and application of Bt rice and maize in China are discussed. This article provides a general context for colleagues to learn about research and development of Bt crops in China, and may shed light on future work in this field. PMID:27763554

  5. Comparative Analysis of Genomics and Proteomics in the New Isolated Bacillus thuringiensis X022 Revealed the Metabolic Regulation Mechanism of Carbon Flux Following Cu(2+) Treatment.

    Science.gov (United States)

    Quan, Meifang; Xie, Junyan; Liu, Xuemei; Li, Yang; Rang, Jie; Zhang, Tong; Zhou, Fengjuan; Xia, Liqiu; Hu, Shengbiao; Sun, Yunjun; Ding, Xuezhi

    2016-01-01

    Bacillus thuringiensis (Bt) X022 is a novel strain isolated from soil in China, and showed strong insecticidal activity against several Lepidopteran pests. In this work, we performed whole genome sequencing of this Bt strain using the next-generation sequencing technology, and further conducted a comparative analysis with the proteomics data of the specific spore-release period based on LC-MS/MS approach. The Bt X022 genome consisted of one circular chromosomal DNA and seven plasmids, which were further functionally annotated using the RAST server. Comparative analysis of insecticidal substances showed that X022 contained genes coding for three Cry proteins (Cry1Ac, Cry1Ia and Cry2Ab) and a vegetative insecticidal protein (Vip3A). However, three insecticidal crystal proteins (ICPs) (Cry1Ca, Cry1Ac and Cry1Da) were detected by proteomics in the spore-release period. Moreover, a putative biosynthetic gene cluster and the metabolic pathway for poly-β-hydroxybutyrate in Bt X022 were deduced based on the comparative analysis of genomic and proteomic data, which revealed the metabolic regulation mechanism of carbon flux correlated with increased production of ICPs caused by Cu(2+.) Hence, these results provided a deeper understanding of the genetic background and protein expression profile of Bt X022. This study established a foundation for directed genetic modification and further application of this new isolated Bt strain. PMID:27303381

  6. Comparative Analysis of Genomics and Proteomics in the New Isolated Bacillus thuringiensis X022 Revealed the Metabolic Regulation Mechanism of Carbon Flux Following Cu2+ Treatment

    Science.gov (United States)

    Quan, Meifang; Xie, Junyan; Liu, Xuemei; Li, Yang; Rang, Jie; Zhang, Tong; Zhou, Fengjuan; Xia, Liqiu; Hu, Shengbiao; Sun, Yunjun; Ding, Xuezhi

    2016-01-01

    Bacillus thuringiensis (Bt) X022 is a novel strain isolated from soil in China, and showed strong insecticidal activity against several Lepidopteran pests. In this work, we performed whole genome sequencing of this Bt strain using the next-generation sequencing technology, and further conducted a comparative analysis with the proteomics data of the specific spore-release period based on LC-MS/MS approach. The Bt X022 genome consisted of one circular chromosomal DNA and seven plasmids, which were further functionally annotated using the RAST server. Comparative analysis of insecticidal substances showed that X022 contained genes coding for three Cry proteins (Cry1Ac, Cry1Ia and Cry2Ab) and a vegetative insecticidal protein (Vip3A). However, three insecticidal crystal proteins (ICPs) (Cry1Ca, Cry1Ac and Cry1Da) were detected by proteomics in the spore-release period. Moreover, a putative biosynthetic gene cluster and the metabolic pathway for poly-β-hydroxybutyrate in Bt X022 were deduced based on the comparative analysis of genomic and proteomic data, which revealed the metabolic regulation mechanism of carbon flux correlated with increased production of ICPs caused by Cu2+. Hence, these results provided a deeper understanding of the genetic background and protein expression profile of Bt X022. This study established a foundation for directed genetic modification and further application of this new isolated Bt strain. PMID:27303381

  7. Comparative Analysis of Genomics and Proteomics in the New Isolated Bacillus thuringiensis X022 Revealed the Metabolic Regulation Mechanism of Carbon Flux Following Cu(2+) Treatment.

    Science.gov (United States)

    Quan, Meifang; Xie, Junyan; Liu, Xuemei; Li, Yang; Rang, Jie; Zhang, Tong; Zhou, Fengjuan; Xia, Liqiu; Hu, Shengbiao; Sun, Yunjun; Ding, Xuezhi

    2016-01-01

    Bacillus thuringiensis (Bt) X022 is a novel strain isolated from soil in China, and showed strong insecticidal activity against several Lepidopteran pests. In this work, we performed whole genome sequencing of this Bt strain using the next-generation sequencing technology, and further conducted a comparative analysis with the proteomics data of the specific spore-release period based on LC-MS/MS approach. The Bt X022 genome consisted of one circular chromosomal DNA and seven plasmids, which were further functionally annotated using the RAST server. Comparative analysis of insecticidal substances showed that X022 contained genes coding for three Cry proteins (Cry1Ac, Cry1Ia and Cry2Ab) and a vegetative insecticidal protein (Vip3A). However, three insecticidal crystal proteins (ICPs) (Cry1Ca, Cry1Ac and Cry1Da) were detected by proteomics in the spore-release period. Moreover, a putative biosynthetic gene cluster and the metabolic pathway for poly-β-hydroxybutyrate in Bt X022 were deduced based on the comparative analysis of genomic and proteomic data, which revealed the metabolic regulation mechanism of carbon flux correlated with increased production of ICPs caused by Cu(2+.) Hence, these results provided a deeper understanding of the genetic background and protein expression profile of Bt X022. This study established a foundation for directed genetic modification and further application of this new isolated Bt strain.

  8. In vivo fluorescence observation of parasporal inclusion formation in Bacillus thuringiensis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A recombinant gene expressing a Cry1Ac-GFP fusion protein with a molecular mass of approximately 160 kD was constructed to investigate the expression of cry1Ac,the localization of its gene product Cry1Ac,and its role in crystal development in Bacillus thuringiensis.The cry1Ac-gfp fusion gene under the control of the cry1Ac promoter was cloned into the plasmid pHT304,and this construct was designated pHTcry1Ac-gfp.pHTcry1Ac-gfp was transformed into the crystal-negative strain,HD-73 cry-,and the resulting strain was named HD-73-(pHTcry1Ac-gfp).The gfp gene was then inserted into the large HD-73 endogenous plasmid pHT73 and fused with the 3’ terminal of the cry1Ac gene by homologous recombination,yielding HD-73Φ(cry1Ac-gfp)3534.Laser confocal microscopy and Western blot analyses showed for the first time that the Cry1Ac-GFP fusion proteins in both HD-73-(pHTcry1Ac-gfp) and HD-73Φ(cry1Ac-gfp)3534 were produced during asymmetric septum formation.Surprisingly,the Cry1Ac-GFP fusion protein showed polarity and was located near the septa in both strains.There was no significant difference between Cry1Ac-GFP and Cry1Ac in their toxicity to Plutella xylostella larvae.

  9. Stylet penetration behaviors of the cotton aphid Aphis gossypii on transgenic Bt cotton

    Institute of Scientific and Technical Information of China (English)

    Kun Xue; Xiao-Ying Wang; Cui-Hong Huang; Rong-Jiang Wang; Biao Liu; Feng-Ming Yan; Chong-Ren Xu

    2009-01-01

    Stylet penetration behaviors of cotton aphids Aphis gossypii Glover on a tmnsgenic cotton line "GK-12" expressing Bt toxic protein ofCry1A (Bt cotton) and a non-Bt conventional cotton line "Simian-3" (CK cotton) were recorded with the direct current electrical penetration graph (DC-EPG) technique. Cotton aphids reared on Bt cotton (abbreviated as Bt-aphids) and its parental non-Bt control line (CK-aphids) for more than 20 generations each, were used for recordings on two cotton lines. Among 47 selected parameters reflecting the activities of aphid stylets within plant tissues, there were eight parameters of CK-aphids showing significant differences between the performances of CK-aphids on Bt cotton and CK cotton, while for Bt-aphids, all the parameters were statistically equal between the performances on the two cotton lines. All parameters with significant differences indicated that CK-aphids could penetrate into Bt cotton more easily, but the phloem saps of Bt cotton were not as good as those of regular cotton for CK-aphids. Based on the present results, we concluded that there were some factors in Bt cotton affecting penetration behaviors of CK-aphids, but it just took several generations for CK-aphids to completely adapt Bt cotton, and Bt-aphids could feed on two cotton lines without difficulty.

  10. Resistance to Bacillus thuringiensis Toxin Cry2Ab in Trichoplusia ni Is Conferred by a Novel Genetic Mechanism

    OpenAIRE

    Song, Xiaozhao; Kain, Wendy; Cassidy, Douglas; Wang, Ping

    2015-01-01

    The resistance to the Bacillus thuringiensis (Bt) toxin Cry2Ab in a greenhouse-originated Trichoplusia ni strain resistant to both Bt toxins Cry1Ac and Cry2Ab was characterized. Biological assays determined that the Cry2Ab resistance in the T. ni strain was a monogenic recessive trait independent of Cry1Ac resistance, and there existed no significant cross-resistance between Cry1Ac and Cry2Ab in T. ni. From the dual-toxin-resistant T. ni strain, a strain resistant to Cry2Ab only was isolated,...

  11. Effects of root exudates of bivalent transgenic cotton (Bt+CpTI) plants on antioxidant proteins and growth of conventional cotton (Xinluhan 33).

    Science.gov (United States)

    Wu, Hong-Sheng; Shi, Xue; Li, Ji; Wu, Tian-Yu; Ren, Qian-Qi; Zhang, Zhen-Hua; Wang, Ming-Yan; Shang, Xiao-Xia; Liu, Yan; Xiao, Song-Hua

    2016-01-01

    A greenhouse experiment was conducted to assess the adverse impact of transgenic cotton on ecosystem and environment via effect of transgenic Bt+CpTI cotton root exudates on growth and antioxidant activity of conventional parental cotton. Results showed elevated reductive and oxidative species activities in the leaves of conventional parental cotton seedlings treated with varying concentrations of transgenic cotton root exudates. Compared to control, 14.9% to 39.9% increase in catalase, 8.8% to 114% increase in for peroxidase, 21.3% to 59.7% increase in phenylalanine ammonia-lyase and 5.8 to 19.5 fold in ascorbate specific peroxidase was observed. However, biomass and height of conventional cotton seedlings were not affected by any concentration of transgenic cotton root exudates. These results suggested that cultivation of transgenic Bt+CpTI cotton plants poses little risk to conventional parental cotton based on their root interactions. PMID:26930855

  12. The Expression of Bt Toxin Protein in Transgenic Plants%Bt毒蛋白在转基因植物中的表达

    Institute of Scientific and Technical Information of China (English)

    魏俊杰

    2012-01-01

    With the promotion of insect-resistant genetically modified crops and large-scale commercial cultivation,Bt toxin in transgenic plants expression is increasingly attracted attention.In this paper,corn,cotton,rice and other insect-resistant transgenic crops expressing the Bt toxin were discussed.%随着抗虫转基因植物的推广和大面积商业化种植,Bt毒蛋白在转基因植物中的表达引起了人们的重视。综述了玉米、棉花、水稻等抗虫转基因植物的Bt毒蛋白表达及其时空变化规律。

  13. Gene cloning and expression of cadherin in midgut of Helicoverpa armigera and its Cry1A binding region

    Institute of Scientific and Technical Information of China (English)

    WANG; Guirong; WU; Kongming; LIANG; Gemei; GUO; Yuyuan

    2005-01-01

    Cadherins belong to one of the families of animal glycoproteins responsible for calcium-dependent cell-cell adhesion. Recent literatures showed that the cadherin-like in midgut of several insects served as the receptor of Bt toxin Cry1A and the variation of cadherin-like is related to insect's resistance to Cry1A. The full-length cDNA encoding cadherin-like of Helicoverpa armigera is cloned by degenerate PCR and RACE techniques and the gene was designated as BtR-harm, which is 5581 bp in full-length, encoding 1730 amino acid residues (BtR-harm was deposited in GenBank and the accession number is AF519180). Its predicted molecular weight and isoelectric point were 195.39 kDa and 4.23, respectively. The inferred amino acid sequence includes a signal sequence, 11 cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. Sequence analysis indicated that the deduced protein sequence was most similar to the cadherin-like from Heliothis virescens with 84.2% identity and highly similar to three other lepidopteran cadherin from Bombyx mori, Manduca sexta and Pectinophora gossypiella, with the sequence identities of 60.3.6%, 57.5% and 51.0%, respectively. The cDNA encoding cadherin gene was expressed successfully in E. coli and the recombinant proteins can bind with Cry1Ac. Truncation analysis and binding experiment of BtR-harm revealed that the Cry1A binding region was a contiguous 244-amino acid sequence, which located between amino acid 1217 and 1461. Semi-quantitative RT-PCR analysis showed that BtR-harm was highly expressed in midgut of H. armigera, very low expressed in foregut and hindgut and was not expressed in other tissues. After H. armigera producing resistance to Cry1Ac, the expression quantity of BtR-harm significantly decreased in midgut of H. armigera. It is the first confirmation that BtR-harm can function as receptor of Cry1Ac in H. armigera and the binding region was located on a contiguous 244 amino acid sequence

  14. Gene cloning and expression of cadherin in midgut of Helicoverpa armigera and its Cry1A binding region.

    Science.gov (United States)

    Wang, Guirong; Wu, Kongming; Liang, Gemei; Guo, Yuyuan

    2005-08-01

    Cadherins belong to one of the families of animal glycoproteins responsible for calcium-dependent cell-cell adhesion. Recent literatures showed that the cadherin-like in midgut of several insects served as the receptor of Bt toxin Cry1A and the variation of cadherin-like is related to insect's resistance to Cry1A. The full-length cDNA encoding cadherin-like of Helicoverpa armigera is cloned by degenerate PCR and RACE techniques and the gene was designated as BtR-harm, which is 5581 bp in full-length, encoding 1730 amino acid residues (BtR-harm was deposited in GenBank and the accession number is AF519180). Its predicted molecular weight and isoelectric point were 195.39 kDa and 4.23, respectively. The inferred amino acid sequence includes a signal sequence, 11 cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. Sequence analysis indicated that the deduced protein sequence was most similar to the cadherin-like from Heliothis virescens with 84.2% identity and highly similar to three other lepidopteran cadherin from Bombyx mori, Manduca sexta and Pectinophora gossypiella, with the sequence identities of 60.3.6%, 57.5% and 51.0%, respectively. The cDNA encoding cadherin gene was expressed successfully in E. coli and the recombinant proteins can bind with Cry1Ac. Truncation analysis and binding experiment of BtR-harm revealed that the Cry1A binding region was a contiguous 244-amino acid sequence, which located between amino acid 1217 and 1461. Semi-quantitative RT-PCR analysis showed that BtR-harm was highly expressed in midgut of H. armigera, very low expressed in foregut and hindgut and was not expressed in other tissues. After H. armigera producing resistance to Cry1Ac, the expression quantity of BtR-harm significantly decreased in midgut of H. armigera. It is the first confirmation that BtR-harm can function as receptor of Cry1Ac in H. armigera and the binding region was located on a contiguous 244 amino acid sequence

  15. Development and Adoption of Bt Cotton in India : Economic, Environmental and Health Issues

    OpenAIRE

    -, Dr S Saravanan; -, Dr V Mohanasundaram

    2016-01-01

    Bt Cotton, is genetically engineered with Bt (Bacillus thuringiensis), a bio-toxin which comes from soil bacterium. Bt which was isolated from soil in 1911, has been available to farmers as an organic pesticide since 1930..The engineered Bt gene produces a protein that cuts into the guts of specific insects, rendering the cotton resistant to these insects. Biotechnology for control of bollworms is made available in the seed itself. Farmers have to just sow the Bt cotton seeds as they do with...

  16. Bt crops benefit natural enemies to control non-target pests.

    Science.gov (United States)

    Tian, Jun-Ce; Yao, Ju; Long, Li-Ping; Romeis, Jörg; Shelton, Anthony M

    2015-11-12

    Crops producing insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) control important lepidopteran pests. However, pests such as aphids not susceptible to Cry proteins may require other integrated pest management (IPM) tactics, including biological control. We fed aphids on Bt and non-Bt plants and analyzed the Bt protein residue in aphids and compared the effects of Bt plants and a pyrethroid, lambda-cyhalothrin, on the performance of three natural enemies (predators: Coleomegilla maculata and Eupeodes americanus; parasitoid Aphidius colemani) of the green peach aphid, Myzus persicae. No Bt protein residues in aphids were detected and no significant differences were recorded in the performance of pyrethroid-resistant aphids that fed on Bt broccoli expressing Cry1Ab or Cry1C, or on non-Bt broccoli plants treated or not treated with the pyrethroid. This indicated the aphids were not affected by the Cry proteins or the pyrethroid, thus removing any effect of prey quality. Tri-trophic experiments demonstrated that no C. maculata and E. americanus survived consumption of pyrethroid-treated aphids and that ovipositional behavior of A. colemani was impaired when provided with pyrethroid-treated aphids. In contrast, natural enemies were not affected when fed aphids reared on Bt broccoli, thus demonstrating the safety of these Bt plants for IPM.

  17. Effects of Transgenic Bt Rice on Nontarget Rhopalosiphum maidis (Homoptera: Aphididae).

    Science.gov (United States)

    Ren, Shao-Peng; Yang, Fan; Gao, Ming-Qing; Pu, De-Qiang; Shi, Min; Ye, Gong-Yin; Shen, Zhi-Cheng; Chen, Xue-Xin

    2016-08-01

    The effects of three transgenic Bacillus thuringiensis (Bt) rice lines, KMD1, KMD2, and G8-7, on biological parameters and population dynamics of nontarget insect, Rhopalosiphum maidis (Fitch) (Homoptera: Aphididae), were investigated in the laboratory and field. No significant differences were found between Bt and non-Bt rice lines for aphid survival. The developmental time of R. maidis that fed on KMD1 and KMD2 did not differ significantly from those of the individuals feeding on the parental variety Xiushui11, but significantly prolonged developmental time was observed on G8-7 as compared with its parental variety Xiushui110. Aphid fecundity was significantly higher on Bt than on parental rice. A 2-yr field survey indicated that Bt rice did not significantly affect the population dynamics of R. maidis in comparison with non-Bt rice. Additionally, guttation droplets of Bt rice and aphids feeding on Bt rice were analyzed for presence of Cry1Ab using ELISA. No Cry1Ab protein was found in aphid adults feeding on Bt rice lines both in the laboratory and field. By using the guttation droplets from the top of rice seedlings, we designed a novel method to collect phloem sap, and found that relatively low concentrations were detected in the guttation droplets from Bt rice lines. In conclusion, although the Bt rice lines tested in this study stimulate the fecundity of R. maidis, the aphid population density did not increase in Bt rice fields. PMID:27389683

  18. Three cadherin alleles associated with resistance to Bacillus thuringiensis in pink bollworm

    Science.gov (United States)

    Morin, Shai; Biggs, Robert W.; Sisterson, Mark S.; Shriver, Laura; Ellers-Kirk, Christa; Higginson, Dawn; Holley, Daniel; Gahan, Linda J.; Heckel, David G.; Carrière, Yves; Dennehy, Timothy J.; Brown, Judith K.; Tabashnik, Bruce E.

    2003-01-01

    Evolution of resistance by pests is the main threat to long-term insect control by transgenic crops that produce Bacillus thuringiensis (Bt) toxins. Because inheritance of resistance to the Bt toxins in transgenic crops is typically recessive, DNA-based screening for resistance alleles in heterozygotes is potentially much more efficient than detection of resistant homozygotes with bioassays. Such screening, however, requires knowledge of the resistance alleles in field populations of pests that are associated with survival on Bt crops. Here we report that field populations of pink bollworm (Pectinophora gossypiella), a major cotton pest, harbored three mutant alleles of a cadherin-encoding gene linked with resistance to Bt toxin Cry1Ac and survival on transgenic Bt cotton. Each of the three resistance alleles has a deletion expected to eliminate at least eight amino acids upstream of the putative toxin-binding region of the cadherin protein. Larvae with two resistance alleles in any combination were resistant, whereas those with one or none were susceptible to Cry1Ac. Together with previous evidence, the results reported here identify the cadherin gene as a leading target for DNA-based screening of resistance to Bt crops in lepidopteran pests. PMID:12695565

  19. Can Conventional Crop Producers Also Benefit From Bt Technology?

    OpenAIRE

    Dun, Zhe; Mitchell, Paul D.

    2011-01-01

    Transgenic plants producing insecticidal protein derived from Bacillus thuringiensis (Bt) have been widely adopted since their commercial introduction in 1996. In 2009, 25 countries planted 134 million ha of transgenic crops. The widespread adoption of such plants has reduced use of conventional insecticides while attaining yield gains, thus providing economic, environmental and human health benefits. Because of Bt crops’ high pest control efficacy, there is concern that pests will develop re...

  20. Biointensive Integrated Pest Management for Bt Cotton

    OpenAIRE

    N. Sathiah; Balagurunathan, R.; P.S. Shanmugam

    2006-01-01

    Biointensive Integrated Pest Management (BIPM) modules were compared with the Farmers` Package of Practices (FPP) for MECH 162 Bt and MECH 162 N Bt The incidence of leaf hopper, aphids, thrips and whiteflies in different modules was in the order of FPP-MECH 162 Bt > BIPM MECH 162 Bt > BIPM MECH 162 N Bt > FPP MECH 162 N Bt. Natural enemies population were more in BIPM modules than the FPP. Coccinellids such as Menochilus sexmaculatus, Coccinella transversalis and spiders Oxyopes spp., Argiope...

  1. THE EFFECT OF ARTIFICIAL INOCULATION WITH SELECTED FUSARIUM STRAINS ON NUTRITIONAL QUALITY AN ENSILING PROCESS OF BT MAIZE

    Directory of Open Access Journals (Sweden)

    Ludmila KŘÍŽOVÁ

    2011-01-01

    Full Text Available The objective of the study was to compare the nutritive value and mycotoxin content of maize forage and silage of near isogenic control MONUMENTAL (C and Bt maize (MONSANTO, MON 810 that was either untreated (Bt or artificially inoculated with Fusarium strains (I-Bt. The inoculation was made in the growing crop in milk stage of maturity. Plants were harvested at the soft dough stage of maturity and ensiled in microsilage tubes. The content of forage dry matter (DM was 307.6 g/kg in C, 306.9 g/kg in Bt and 298.0 g/kg in I-Bt. All forages were positive for deoxynivalenol, aflatoxin, fumonisins and zearalenone (P>0.05. Content of DM was the lowest in I-Bt silage (285.5 g/kg and differed significantly from C (296.7 g/kg or Bt (303.7 g/kg, P<0.05. Content of crude protein (CP was the lowest in I-Bt silage (79.0 g/kg and differed significantly from C or Bt (85.7 or 81.9 g/kg, respectively, P<0.05. Silages Bt and I-Bt had lower pH (3.93 and 3.96, respectively than silage C (4.02, P<0.05. Silage I-Bt tended to have a higher degree of proteolysis 9.18 % measured as N-NH3 (% of total N than silages C or Bt (8.64 or 8.9 %, respectively, P>0.05. Lactic acid was predominant product of fermentation in all silages, however silage I-Bt tended to have lower content of lactic acid (20.96 g/kg than C or Bt (24.76 or 23.82 g/kg, P>0.05. I-Bt silage contained lower levels of eoxynivalenol (602 ppb than C or Bt silage (748 and 690 ppb, respectively, P<0.05. Content of fumonisins and zearalenone in C did not differ from I-Bt (P<0.05 but both were lower than in Bt (P<0.05. In conclusion, nutritional value a fermentation parameters of Bt silage were similar to C except of CP content and pH that was lower in Bt (P<0.05. I-Bt silage had lower content of DM, CP and fat than Bt silage (P<0.05. Controversially, concentrations of mycotoxins in I-Bt silage were lower than in Bt.

  2. Bt crop effects on functional guilds of non-target arthropods: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    L LaReesa Wolfenbarger

    Full Text Available BACKGROUND: Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt. We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of Bt cotton, maize and potato on the abundance and interactions of arthropod non-target functional guilds. METHODOLOGY/PRINCIPAL FINDINGS: We compared the abundance of predators, parasitoids, omnivores, detritivores and herbivores under scenarios in which neither, only the non-Bt crops, or both Bt and non-Bt crops received insecticide treatments. Predators were less abundant in Bt cotton compared to unsprayed non-Bt controls. As expected, fewer specialist parasitoids of the target pest occurred in Bt maize fields compared to unsprayed non-Bt controls, but no significant reduction was detected for other parasitoids. Numbers of predators and herbivores were higher in Bt crops compared to sprayed non-Bt controls, and type of insecticide influenced the magnitude of the difference. Omnivores and detritivores were more abundant in insecticide-treated controls and for the latter guild this was associated with reductions of their predators in sprayed non-Bt maize. No differences in abundance were found when both Bt and non-Bt crops were sprayed. Predator-to-prey ratios were unchanged by either Bt crops or the use of insecticides; ratios were higher in Bt maize relative to the sprayed non-Bt control. CONCLUSIONS/SIGNIFICANCE: Overall, we find no uniform effects of Bt cotton, maize and potato on the functional guilds of non-target arthropods. Use of and type of insecticides influenced the magnitude and direction of effects; insecticde effects were much larger than those of Bt crops. These meta-analyses underscore the importance of using controls not only to isolate the effects of a Bt crop per se but also to reflect the replacement of existing agricultural practices. Results will

  3. Biointensive Integrated Pest Management for Bt Cotton

    Directory of Open Access Journals (Sweden)

    N. Sathiah

    2006-01-01

    Full Text Available Biointensive Integrated Pest Management (BIPM modules were compared with the Farmers` Package of Practices (FPP for MECH 162 Bt and MECH 162 N Bt The incidence of leaf hopper, aphids, thrips and whiteflies in different modules was in the order of FPP-MECH 162 Bt > BIPM MECH 162 Bt > BIPM MECH 162 N Bt > FPP MECH 162 N Bt. Natural enemies population were more in BIPM modules than the FPP. Coccinellids such as Menochilus sexmaculatus, Coccinella transversalis and spiders Oxyopes spp., Argiope spp., Neoscona spp., Araenus spp. and Plexippus spp. were frequently observed in the field trials. Incidence of bollworm population was more in winter field trial than that in the summer field trials. Fruiting bodies damage, open boll, locule and inter locule damage in different modules was in the order of BIPM MECH 162 Bt > FPP MECH 162 Bt > BIPM MECH 162 N Bt > FPP MECH 162 N Bt. Seed cotton yield in BIPM MECH 162 Bt, BIPM MECH 162 N Bt, FPP MECH 162 Bt and FPP MECH 162 N Bt modules at Alandurai field trial were 1920, 1640, 1800 and 1440 kg ha-1. The results indicated the better performance of Bt cotton in both the modules. BIPM approach reduces the insecticide usage. The IPM approach is essential for gaining higher advantage from Bt cotton as it takes care of varying pest situation.

  4. Harmonia axyridis (Coleoptera: Coccinellidae exhibits no preference between Bt and non-Bt maize fed Spodoptera frugiperda (Lepidoptera: Noctuidae.

    Directory of Open Access Journals (Sweden)

    Carla C Dutra

    Full Text Available A recent shift in managing insect resistance to genetically engineered (GE maize consists of mixing non-GE seed with GE seed known as "refuge in a bag", which increases the likelihood of predators encountering both prey fed Bt and prey fed non-Bt maize. We therefore conducted laboratory choice-test feeding studies to determine if a predator, Harmonia axyridis, shows any preference between prey fed Bt and non-Bt maize leaves. The prey species was Spodoptera frugiperda, which were fed Bt maize (MON-810, expressing the single Cry1Ab protein, or non-Bt maize. The predators were third instar larvae and female adults of H. axyridis. Individual predators were offered Bt and non-Bt fed prey larvae that had fed for 24, 48 or 72 h. Ten and 15 larvae of each prey type were offered to third instar and adult predators, respectively. Observations of arenas were conducted at 1, 2, 3, 6, 15 and 24 h after the start of the experiment to determine the number and type of prey eaten by each individual predator. Prey larvae that fed on non-Bt leaves were significantly larger than larvae fed Bt leaves. Both predator stages had eaten nearly all the prey by the end of the experiment. However, in all combinations of predator stage and prey age, the number of each prey type consumed did not differ significantly. ELISA measurements confirmed the presence of Cry1Ab in leaf tissue (23-33 µg/g dry weight and S. frugiperda (2.1-2.2 µg/g, while mean concentrations in H. axyridis were very low (0.01-0.2 µg/g. These results confirm the predatory status of H. axyridis on S. frugiperda and that both H. axyridis adults and larvae show no preference between prey types. The lack of preference between Bt-fed and non-Bt-fed prey should act in favor of insect resistance management strategies using mixtures of GE and non-GE maize seed.

  5. Food Safety of Bt Cry Proteins from Biotechnology-derived Crops%转基因抗虫作物中苏云金芽孢杆菌Cry蛋白的食品安全问题

    Institute of Scientific and Technical Information of China (English)

    王春玲; Bruce Hammond

    2011-01-01

    苏云金芽孢杆菌(Bt)微生物制剂是农业、林业和饮用水等领域用来控制靶标害虫幼虫的有效工具,至今已经有50余年的使用历史。同时其在美国、欧洲和其他一些国家被广泛用于经过认证的有机农业生产之中。目前已获审批的转基因Bt作物中最常使用的是Cry蛋白。Cry蛋白的作用机制、食品安全性以及致敏性已经经过啮齿类动物、农场动物和人体内试验和生物信息学研究的严格检验。Cry蛋白的杀虫作用只在靶标害虫的碱性消化道内,与中肠上皮细胞的特异蛋白受体结合才能起到杀虫作用,而其他非靶标生物体内(人类、猕猴、小鼠、大鼠和牛等)都被证明没有这种特异蛋白质受体。美国、欧洲和其他国家的管理机构都已经证实了转基因Bt作物和Cry蛋白在农作物和饮用水中残留的安全性。食物加工过程能够最大化地减少转基因作物中功能性Cry蛋白的摄入。转基因抗虫作物有利于降低农药杀虫剂的使用的同时,也能够有效防止玉米中伏马菌毒素的污染。%Bt microbial insecticides have been used to control larval insect pests that feed on agricultural crops, forest and drinking water for over 50 years. They are also widely used in certified organic agricultural food production in the United States, Europe and other countries. Cry proteins are most commonly introduced in registered Bt crops. Mode of action, food safety and allergenicity of Cry protein have been rigorously tested using rodent, farm animals, and human experiment and bioinformatics research tools. The insecticidal function of Cry protein only works in the alkaline environment of the insect gut where specific receptors on the membranes of midgut epithelial cells present. Other non-target organisms (humans, rhesus monkeys, mice, rats and cows etc.) lack these receptors. Regulatory agencies in US, EU and other countries have confirmed the history

  6. Effects of Transgenic Cry 1 Ac plus CpTI Cotton on the Bioecology of Main Parasitoids in Laboratory Studies

    Institute of Scientific and Technical Information of China (English)

    CUI Jin-jie; VANDER Weft Wopke; MA Yah; LUO Jun-yu

    2008-01-01

    @@ Effects of transgenic CrylAc plus CpTI cotton (double genes cotton) on development of main parasitoids were studied in the laboratory.Compared with the traditional cotton,the differences of the moulting rate and adult weight of cotton aphid-Aphydius from double gene cotton field were not obvious.

  7. Toxicity and mode of action of insecticidal Cry1A proteins from Bacillus thuringiensis in an insect cell line, CF-1.

    Science.gov (United States)

    Portugal, Leivi; Gringorten, J Lawrence; Caputo, Guido F; Soberón, Mario; Muñoz-Garay, Carlos; Bravo, Alejandra

    2014-03-01

    Bacillus thuringiensis Cry toxins are insecticidal proteins used to control insect pests. The interaction of Cry toxins with the midgut of susceptible insects is a dynamic process involving activation of the toxin, binding to midgut receptors in the apical epithelium and conformational changes in the toxin molecule, leading to pore formation and cell lysis. An understanding of the molecular events underlying toxin mode of action is essential for the continued use of Cry toxins. In this work, we examined the mechanism of action of Cry1A toxins in the lepidopteran cell line CF-1, using native Cry1Ab and mutant forms of this protein that interfer with different steps in the mechanism of action, specifically, receptor binding, oligomerization or pore formation. These mutants lost activity against both Manduca sexta larvae and CF-1 cells. We also analyzed a mutation created in domain I of Cry1Ab, in which helix α-1 and part of helix α-2 were deleted (Cry1AbMod). Cry1AbMod is able to oligomerize in the absence of toxin receptors, and although it shows reduced activity against some susceptible insects, it kills insect pests that have developed resistance to native Cry1Ab. Cry1AbMod showed enhanced toxicity to CF-1, suggesting that oligomerization of native Cry1Ab may be a limiting step in its activity against CF-1 cells. The toxicity of Cry1Ac and Cry1AcMod were also analyzed. Our results suggest that some of the steps in the mode of action of Cry1A toxins are conserved in vivo in insect midgut cells and in vitro in an established cell line, CF-1. PMID:24189038

  8. Cry toxin mode of action in susceptible and resistant Heliothis virescens larvae.

    Science.gov (United States)

    Jurat-Fuentes, Juan Luis; Adang, Michael J

    2006-07-01

    Many pest insect species are effectively controlled by Bacillus thuringiensis (Bt) Cry toxins delivered in plants and biopesticides. Since the insect midgut epithelium contains receptors and other molecules that determine Bt toxicity, characterization of these molecules is necessary for sustained usage of Bt toxins. Studies of Bt susceptible and resistant strains of Heliothis virescens have provided insights into resistance mechanisms and toxin receptors. For example, the first gene identified as involved in high levels of Cry1Ac resistance in H. virescens encodes a cadherin-like protein, a functional Cry1A receptor in Lepidoptera. This manuscript discusses the most updated information on the mode of action of Cry1A toxins obtained from the characterization of resistant mechanisms in H. virescens strains. Our studies are focused on biochemical and molecular comparison of a susceptible and three resistant H. virescens strains to identify alterations that correlate with toxin resistance. Following this approach we have been able to identify an alkaline phosphatase (HvALP) as a potential receptor and tested the utility of this protein as a marker for resistance to Cry1Ac. Comparison of brush border proteomes from susceptible and resistant larvae has allowed us to identify additional molecules directly involved in the toxicity process. PMID:16797583

  9. Modeling evolution of resistance of sugarcane borer (Lepidoptera: Crambidae) to transgenic Bt corn.

    Science.gov (United States)

    Kang, J; Huang, F; Onstad, D W

    2014-08-01

    Diatraea saccharalis (F.) (Lepidoptera: Crambidae) is a target pest of transgenic corn expressing Bacillus thuringiensis (Bt) protein, and the first evidence of resistance by D. saccharalis to Cry1Ab corn was detected in a field population in northeast Louisiana in 2004. We used a model of population dynamics and genetics of D. saccharalis to 1) study the effect of interfield dispersal, the first date that larvae enter diapause for overwintering, toxin mortality, the proportion of non-Bt corn in the corn patch, and the area of a crop patch on Bt resistance evolution; and 2) to identify gaps in empirical knowledge for managing D. saccharalis resistance to Bt corn. Increasing, the proportion of corn refuge did not always improve the durability of Bt corn if the landscape also contained sugarcane, sorghum, or rice. In the landscape, which consisted of 90% corn area, 5% sorghum area, and 5% rice area, the durability of single-protein Bt corn was 40 yr when the proportion of corn refuge was 0.2 but 16 yr when the proportion of corn refuge was 0.5. The Bt resistance evolution was sensitive to a change (from Julian date 260 to 272) in the first date larvae enter diapause for overwintering and moth movement. In the landscapes with Bt corn, non-Bt corn, sugarcane, sorghum, and rice, the evolution of Bt resistance accelerated when larvae entered diapause for overwintering early. Intermediate rates of moth movement delayed evolution of resistance more than either extremely low or high rates. This study suggested that heterogeneity in the agrolandscapes may complicate the strategy for managing Bt resistance in D. saccharalis, and designing a Bt resistance management strategy for D. saccharalis is challenging because of a lack of empirical data about overwintering and moth movement.

  10. The food and environmental safety of Bt crops

    OpenAIRE

    Koch, Michael S.; Jason M Ward; Levine, Steven L.; Baum, James A.; Vicini, John L.; Hammond, Bruce G.

    2015-01-01

    Bacillus thuringiensis (Bt) microbial pesticides have a 50-year history of safety in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s). Additionally, the domains...

  11. The Food and Environmental Safety of Bt Crops

    OpenAIRE

    Michael Stephen Koch; Jason M Ward; Levine, Steven L.; Baum, James A.; Vicini, John L.; Hammond, Bruce G.

    2015-01-01

    Bt (Bacillus thuringiensis) microbial pesticides have a 50-year history of safe use in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s). Additionally, the domai...

  12. Comparing gene expression profiles between Bt and non-Bt rice in response to brown planthopper infestation

    Directory of Open Access Journals (Sweden)

    Fang eWang

    2015-12-01

    Full Text Available Bt proteins are the most widely used insecticidal proteins in transgenic crops for improving insect resistance. We previously observed longer nymphal developmental duration and lower fecundity in brown planthopper (BPH fed on Bt rice line KMD2, although Bt insecticidal protein Cry1Ab could rarely concentrate in this non-target rice pest. In the present study, we performed microarray analysis in an effort to detect Bt-independent variation, which might render Bt rice more defensive and/or less nutritious to BPH. We detected 3,834 and 3,273 differentially expressed probe-sets in response to BPH infestation in non-Bt parent Xiushui 11 and Bt rice KMD2, respectively, only 439 of which showed significant differences in expression between rice lines. Our analysis revealed a shift from growth to defense responses in response to BPH infestation, which was also detected in many other studies of plants suffering biotic and abiotic stresses. Chlorophyll biosynthesis and basic metabolism pathways were inhibited in response to infestation. IAA and GA levels decreased as a result of the repression of biosynthesis-related genes or the induction of inactivation-related genes. In accordance with these observations, a number of IAA-, GA-, BR-signaling genes were downregulated in response to BPH. Thus, the growth of rice plants under BPH attack was reduced and defense related hormone signaling like JA, SA and ET were activated. In addition, growth-related hormone signaling pathways, such as GA, BR and auxin signaling pathways, as well as ABA, were also found to be involved in BPH-induced defense. On the other side, 51 probe-sets (represented 50 genes that most likely contribute to the impact of Bt rice on BPH were identified, including three early nodulin genes, four lipid metabolic genes, 14 stress response genes, three TF genes and genes with other functions. Two transcription factor genes, bHLH and MYB, together with lipid transfer protein genes LTPL65 and

  13. Heliothis virescens and Bt cotton in the United States.

    Science.gov (United States)

    Blanco, Carlos A

    2012-01-01

    The tobacco budworm (TBW), Heliothis virescens (F.), has been responsible for substantial economic losses, environmental pollution and a great challenge to the United States' economy, environment, researchers and cotton and tobacco producers during most of the past two hundred years. If a historical description of this pest problem should be written, it would necessarily be divided into two main events; the pre- and post-Bacillus thuringiensis-expressing (Bt)-cotton era. Before the advent of Bt-cotton, TBW had evolved resistance to most commercial insecticides, making cotton cultivation unfeasible at some point. Subsequently, a variety of clever control measures were developed in an effort to develop more sustainable integrated pest management programs. Without a doubt, Bt-cotton, transformed to produce insecticidal proteins from the soil borne bacterium, B. thuringiensis, is now one of the most important elements of TBW management in US cotton. This discussion could be quite short stating that Bt-cotton has produced an unprecedented level of control for TBW, but beyond this, it is important to note the additional impacts around the argument that Bt-cotton has likely reduced TBW populations over large areas-due to its high efficacy-to the low densities observed today. Cotton area suitable for TBW development has been reduced to ~40% of its pre Bt-cotton years and certainly may be another primary force behind this decline. However, the way we have detected this decline relies mostly on observations made in cotton fields, as well as males trapped in pheromone traps near cotton; these monitoring tools may not fully reflect TBW population levels at the landscape level. My argument supports what has been postulated before that TBW may be in the process of differentiating into "host races" and the cotton host race, once the most abundant in the environment, may be the one greatly affected by this habitat modification now dominated by Bt-cotton, while the other host races

  14. Nye oplysninger om bl.a. miljømæssig risikovurdering af PAT-protein og glufosinatammonium herbicider. Zea mays (Bt11). Supplerende materiale om Bt11. Modtaget 21-02-2005, deadline 29-03-2005, svar 07-03-2005

    DEFF Research Database (Denmark)

    Strandberg, Morten Tune

    2005-01-01

    Mail: Det tilsendte supplerende materiale om Bt-11 majsen (mail pr. 21-02-2005) omhandler bl.a. eventuelle uønskede konsekvenser ved ulovlig anvendelse af glufosinat ammonium herbicider i forbindelse med dyrkningen. Vi har allerede indraget dette aspekt i forbindelse med den økologiske risikovurd...

  15. Glial fibrillary acidic protein (GFAP) immunoreactivity correlates with cortical perfusion parameters determined by bolus tracking arterial spin labelling (bt-ASL) magnetic resonance (MR) imaging in the Wistar Kyoto rat.

    Science.gov (United States)

    Gormley, Shane; Rouine, Jennifer; McIntosh, Allison; Kerskens, Christian; Harkin, Andrew

    2016-06-01

    Alterations in astrocyte number and function have been implicated in the pathophysiology of a number of psychiatric disorders. The development of magnetic resonance imaging (MRI) as a tool in the animal laboratory has enabled an investigation of the relationship between pathological and neuroimaging markers in animal models. However the physiological processes which underlie these markers and their role in mediating behavioural deficits is still poorly understood. Rodent models have provided us with important insights into physiological and cellular mechanisms which may mediate anxiety and depression-related behaviours. The Wistar-Kyoto (WKY) rat is a strain which endogenously expresses highly anxious and depressive-like behaviours and has previously been reported to exhibit alterations in immunoreactivity for the astrocytic marker glial fibrillary acidic protein (GFAP) in brain sub-regions relative to more stress resilient out-bred strains. Here we report that the depressive and anxiety-like behaviours exhibited by the WKY rat strain are associated with alterations in brain morphology including a decrease in hippocampal volume, coupled with reduced resting state frontal cortical perfusion as assessed by MR bolus tracking arterial spin labelling (bt-ASL) relative to the out-bred Wistar strain. Pre-limbic cortical GFAP immunoreactivity and astrocyte cell number were positively correlated with cortical blood perfusion in the WKY strain. These experiments provide a link between pathological and neuroimaging markers of aberrant astrocytic function and add validity to the WKY rat as a model for co-morbid anxiety and depression. PMID:27068181

  16. Bt crop effects on functional guilds of non-target arthropods: A meta-analysis (journal)

    Science.gov (United States)

    Background: Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt). We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of...

  17. The end of a myth—Bt (Cry1Ab) maize does not harm green lacewings

    Science.gov (United States)

    Romeis, Jörg; Meissle, Michael; Naranjo, Steven E.; Li, Yunhe; Bigler, Franz

    2014-01-01

    A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab) maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies. PMID:25161661

  18. The end of a myth-Bt (Cry1Ab) maize does not harm green lacewings.

    Science.gov (United States)

    Romeis, Jörg; Meissle, Michael; Naranjo, Steven E; Li, Yunhe; Bigler, Franz

    2014-01-01

    A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab) maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies.

  19. Insecticidal Mechanism of Bt Vegetative Insecticidal Proteins and their Application in GM Crops%新型Bt杀虫蛋白:VIP杀虫的机理与植物转基因应用

    Institute of Scientific and Technical Information of China (English)

    刘辰; 谢柳; 张文飞

    2008-01-01

    苏云金芽孢杆菌(Bacillus thuringiensis,简称 Bt)是目前应用最多的生物杀虫剂.它能够产生多种杀虫因子,其中最主要是杀虫晶体蛋白(insecticidal crystal proteins.ICP)和营养期杀虫蛋(vegetative insecticidal protein,VIP).VIP在Bt营养期生长阶段开始分泌,它们不形成蛋白晶体,和ICP在进化上没有同源性.VIP的杀虫活性很高,达到了纳克级水平,为一类新型杀虫蛋白,被认为是第二代生物杀虫剂.VIP根据蛋白质序列同源性主要分为三类:VIP1、VIP2和VIP3.VIP1和VIP2共同构成二元毒素对鞘翅目萤叶甲科昆虫具有特异性毒杀作用,VIP3对鳞翅目害虫具有很高的杀虫活性.由于VIP对一些可能对ICP产生抗性的害虫具有高效的毒杀作用,而且害虫对ICP和VIP产生交互抗性的几率也很小,因此转VIP植物研究受到了科学家的青睐,并已有不少成功的报道和专利.目前为止,已经利用V1P3构建了转基因水稻、转基因玉米、转基因棉花等多种转基冈作物.

  20. The food and environmental safety of Bt crops.

    Science.gov (United States)

    Koch, Michael S; Ward, Jason M; Levine, Steven L; Baum, James A; Vicini, John L; Hammond, Bruce G

    2015-01-01

    Bacillus thuringiensis (Bt) microbial pesticides have a 50-year history of safety in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s). Additionally, the domains of different but structurally conserved Cry proteins can be combined to produce chimeric proteins with enhanced insecticidal properties. Environmental studies are performed and include invertebrates, mammals, and avian species. Mammalian studies used to support the food and feed safety assessment are also used to support the wild mammal assessment. In addition to the NTO assessment, the environmental assessment includes a comparative assessment between the Bt crop and the appropriate conventional control that is genetically similar but lacks the introduced trait to address unintended effects. Specific phenotypic, agronomic, and ecological characteristics are measured in the Bt crop and the conventional control to evaluate whether the introduction of the insect resistance has resulted in any changes that might cause ecological harm in terms of altered weed characteristics, susceptibility to pests, or adverse environmental impact. Additionally, environmental interaction data are collected in field experiments for Bt crop to evaluate potential adverse effects. Further to the agronomic and phenotypic evaluation, potential movement of transgenes from a genetically modified crop plants into wild relatives is assessed for a new pest resistance gene in a new crop. This review summarizes the evidence for safety of crops containing Cry proteins for humans, livestock, and other non-target organisms.

  1. The Food and Environmental Safety of Bt Crops

    Directory of Open Access Journals (Sweden)

    Michael Stephen Koch

    2015-04-01

    Full Text Available Bt (Bacillus thuringiensis microbial pesticides have a 50-year history of safe use in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s. Additionally, the domains of different but structurally conserved Cry proteins can be combined to produce chimeric proteins with enhanced insecticidal properties. Environmental studies are performed and include invertebrates, mammals and avian species. Mammalian studies used to support the food and feed safety assessment are also used to support the wild mammal assessment. In addition to the NTO assessment, the environmental assessment includes a comparative assessment between the Bt crop and the appropriate conventional control that is genetically similar but lacks the introduced trait to address unintended effects. Specific phenotypic, agronomic, and ecological characteristics are measured in the Bt crop and the conventional control to evaluate whether the introduction of the insect resistance has resulted in any changes that might cause ecological harm in terms of altered weed characteristics, susceptibility to pests, or adverse environmental impact. Additionally, environmental interaction data are collected in field experiments for Bt crop to evaluate potential adverse effects. Further to the agronomic and phenotypic evaluation, potential movement of transgenes from a genetically modified crop plants into wild relatives is assessed for a new pest resistance gene in a new crop. This review summarizes the evidence for safety of crops containing Cry proteins for humans, livestock, and other non-target organisms.

  2. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays

    NARCIS (Netherlands)

    Kirchberger, S.; Leroch, M.; Huynen, M.A.; Wahl, M.; Neuhaus, H.E.; Tjaden, J.

    2007-01-01

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous synth

  3. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays.

    NARCIS (Netherlands)

    Kirchberger, S.; Leroch, M.; Huynen, M.A.; Wahl, M.; Neuhaus, H.E.; Tjaden, J.

    2007-01-01

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous synth

  4. Preparative Purification and Bioassay of Bt Toxin from Cry1Ab Transgenic Rice

    Institute of Scientific and Technical Information of China (English)

    WU Jian-min; YE Qin-fu

    2004-01-01

    A method of extracting and purifying Cry1Ab protein(Bt toxin) from Cry1Ab transgenic rice was established. Most of the Bt toxin present in the tissue of Cry1Ab transgenic rice was extracted effectively with a solution of 50 mmol/LNa2CO3 and NaHCO3. The crude protein containing Bt toxin was obtained after the pretreatment of Cry1Ab transgenic rice with ultra-filtration, ammonium sulfate precipitation and centrifugation. The dialysed crude protein was futher separated on DEAE Sephadex A-50 columns and Sephadex G-150 columns. The protein bound on DEAE Sephadex A-50 gel was eluted with buffer solution B(10 mmol/L trisHCl buffer+1. 0 mmol/L EDTA, pH=8.0) mixed with 0. 1, 0. 3, 0. 5 and 0. 8 mol/L NaCl in a discontinuous gradient elution mode. The peak of the Bt toxin eluted from the columns was identified by ELISA and bioassayed with larvae of tobacco hornworms and silkworms. The purity and the bioactivity of the Bt toxin were determined by means of SDS-PAGE and larvicidal assay, respectively. The purity of the Bt toxin obtained by this method is high, and its insecticidal activity is retained after the toxin is purified.

  5. Apparent digestibility coefficients and consumption of corn silage with and without Bt gene in sheep

    OpenAIRE

    Camila Memari Trava; Mauro Sartori Bueno; Geraldo Balieiro

    2012-01-01

    Corn silage is the most important preserved food for ruminants. The transgenic corn was inserted into the genetic code Bt gene (Bacillus thuringiensis) that expresses a toxic protein to caterpillars pests of maize, reducing production costs. To evaluate the varieties of plant corn silage DKB and AG with or without the Bt gene on the voluntary intake of DM (g/day) and apparent digestibility coefficients (CDA) of nutrients in sheep, the experiment was conducted at the Institute of Animal Scienc...

  6. Pest trade-offs in technology: reduced damage by caterpillars in Bt cotton benefits aphids

    OpenAIRE

    Hagenbucher, Steffen; Felix L Wäckers; Wettstein, Felix E.; Olson, Dawn M.; Ruberson, John R.; Romeis, Jörg

    2013-01-01

    The rapid adoption of genetically engineered (GE) plants that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) has raised concerns about their potential impact on non-target organisms. This includes the possibility that non-target herbivores develop into pests. Although studies have now reported increased populations of non-target herbivores in Bt cotton, the underlying mechanisms are not fully understood. We propose that lack of herbivore-induced secondary metabolit...

  7. Dependence of dielectric properties on BT particle size in EP/BT composites

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaojun; YANG Zhimin; MAO Changhui; DU Jun

    2006-01-01

    The polymer-ceramic composites of epoxy resin (EP) and barium titanate (BT) were prepared.BT powders of different BT particle sizes from 100 nm to 1 μm were used in the preparation.The dielectric properties, such as dielectric constant, dielectric loss and electrical breakdown strength, of the EP/BT composites were studied.The morphology of the composites was characterized by the means of scanning electron microscopy (SEM).The results show that the dielectric constant of the composites is much higher than the epoxy matrix at frequency range from 1 kHz to 10 MHz, and it is also obviously dependent on the size of BT particles.The electrical breakdown strength of the composites decreases with the increase of the BT content.The dependence of electrical breakdown strength on BT particle sizes was also discussed.

  8. Overexpression of a Foreign Bt Gene in Cotton Affects the Low-Molecular-Weight Components in Root Exudates

    Institute of Scientific and Technical Information of China (English)

    YAN Wei-Dong; SHI Wei-Ming; LI Bao-Hai; ZHANG Min

    2007-01-01

    Most research in the past using genetically modified crops (GM crops) has focused on the ecological safety of foreign gene (i.e., the gene flow), gene products (for example, Bt (Bacillus thuringiensis) protein), and the safety of transgenic food for humans. In this study, changes in both the species and amounts of low-molecular-weight components in cotton (Gossypium hirsutum L.) root exudates after foreign Bt gene overexpression were investigated under different nutritional conditions. Transgenic cotton containing Bt (Bt-cotton), supplemented with all the mineral nutrients, secreted more organic acids than the wild-type cotton (WT). When nitrogen was removed from the full-nutrient solution, the amount of organic acids secretion of Bt-cotton was lesser than that of WT. The roots of the transgenic cotton secreted lesser amounts of amino acids and soluble sugars than the WT roots in the full-nutrient solution. Deficiencies of P and K caused a large increase in the total amino acid and soluble sugar secretions of both Bt-cotton and WT, with larger increases observed in Bt-cotton. Because transferring the foreign Bt gene into cotton can result in alterations in the components of the root exudates, with the effect varying depending on the nutritional status, the cultivation of genetically modified crops, such as Bt-cotton, in soil environments should be more carefully assessed, and the possible effects as a result of the alterations in the root exudate components should be considered.

  9. Soil Microbial and Faunal Community Responses to Bt-Maize and Insecticide in Two Soils

    DEFF Research Database (Denmark)

    Griffiths, B. S.; Caul, S.; Thompson, J.;

    2006-01-01

    The effects of maize (Zea mays L.), genetically modified to express the Cry1Ab protein (Bt), and an insecticide on soil microbial and faunal communities were assessed in a glasshouse experiment. Soil for the experiment was taken from field sites where the same maize cultivars were grown to allow...... comparison between results under glasshouse conditions with those from field trials. Plants were grown in contrasting sandy loam and clay loam soils, half were sprayed with a pyrethroid insecticide (deltamethrin) and soil samples taken at the five-leaf stage, flowering, and maturity. The main effect on all...... measured parameters was that of soil type and there were no effects of Bt trait or insecticide on plant growth. The Bt trait resulted in more soil nematodes and protozoa (amoebae), whereas insecticide application increased plant Bt concentration and altered nematode community structure. The only...

  10. Development and Validation of a Fluorescent Multiplexed Immunoassay for Measurement of Transgenic Proteins in Cotton (Gossypium hirsutum).

    Science.gov (United States)

    Yeaman, Grant R; Paul, Sudakshina; Nahirna, Iryna; Wang, Yongcheng; Deffenbaugh, Andrew E; Liu, Zi Lucy; Glenn, Kevin C

    2016-06-22

    In order to provide farmers with better and more customized alternatives to improve yields, combining multiple genetically modified (GM) traits into a single product (called stacked trait crops) is becoming prevalent. Trait protein expression levels are used to characterize new GM products and establish exposure limits, two important components of safety assessment. Developing a multiplexed immunoassay capable of measuring all trait proteins in the same sample allows for higher sample throughput and savings in both time and expense. Fluorescent (bead-based) multiplexed immunoassays (FMI) have gained wide acceptance in mammalian research and in clinical applications. In order to facilitate the measurement of stacked GM traits, we have developed and validated an FMI assay that can measure five different proteins (β-glucuronidase, neomycin phosphotransferase II, Cry1Ac, Cry2Ab2, and CP4 5-enolpyruvyl-shikimate-3-phosphate synthase) present in cotton leaf from a stacked trait product. Expression levels of the five proteins determined by FMI in cotton leaf tissues have been evaluated relative to expression levels determined by enzyme-linked immunosorbent assays (ELISAs) of the individual proteins and shown to be comparable. The FMI met characterization requirements similar to those used for ELISA. Therefore, it is reasonable to conclude that FMI results are equivalent to those determined by conventional individual ELISAs to measure GM protein expression levels in stacked trait products but with significantly higher throughput, reduced time, and more efficient use of resources.

  11. Development and Validation of a Fluorescent Multiplexed Immunoassay for Measurement of Transgenic Proteins in Cotton (Gossypium hirsutum).

    Science.gov (United States)

    Yeaman, Grant R; Paul, Sudakshina; Nahirna, Iryna; Wang, Yongcheng; Deffenbaugh, Andrew E; Liu, Zi Lucy; Glenn, Kevin C

    2016-06-22

    In order to provide farmers with better and more customized alternatives to improve yields, combining multiple genetically modified (GM) traits into a single product (called stacked trait crops) is becoming prevalent. Trait protein expression levels are used to characterize new GM products and establish exposure limits, two important components of safety assessment. Developing a multiplexed immunoassay capable of measuring all trait proteins in the same sample allows for higher sample throughput and savings in both time and expense. Fluorescent (bead-based) multiplexed immunoassays (FMI) have gained wide acceptance in mammalian research and in clinical applications. In order to facilitate the measurement of stacked GM traits, we have developed and validated an FMI assay that can measure five different proteins (β-glucuronidase, neomycin phosphotransferase II, Cry1Ac, Cry2Ab2, and CP4 5-enolpyruvyl-shikimate-3-phosphate synthase) present in cotton leaf from a stacked trait product. Expression levels of the five proteins determined by FMI in cotton leaf tissues have been evaluated relative to expression levels determined by enzyme-linked immunosorbent assays (ELISAs) of the individual proteins and shown to be comparable. The FMI met characterization requirements similar to those used for ELISA. Therefore, it is reasonable to conclude that FMI results are equivalent to those determined by conventional individual ELISAs to measure GM protein expression levels in stacked trait products but with significantly higher throughput, reduced time, and more efficient use of resources. PMID:27177195

  12. Structure of BT-3984, a member of the SusD/RagB family of nutrient-binding molecules

    International Nuclear Information System (INIS)

    The crystal structure of BT-3984, a SusD-family protein, reveals a TPR N-terminal region providing support for a loop-rich C-terminal subdomain and suggests possible interfaces involved in sus complex formation. The crystal structure of the Bacteroides thetaiotaomicron protein BT-3984 was determined to a resolution of 1.7 Å and was the first structure to be determined from the extensive SusD family of polysaccharide-binding proteins. SusD is an essential component of the sus operon that defines the paradigm for glycan utilization in dominant members of the human gut microbiota. Structural analysis of BT-3984 revealed an N-terminal region containing several tetratricopeptide repeats (TPRs), while the signature C-terminal region is less structured and contains extensive loop regions. Sequence and structure analysis of BT-3984 suggests the presence of binding interfaces for other proteins from the polysaccharide-utilization complex

  13. The impact of secondary pests on Bacillus thuringiensis (Bt) crops.

    Science.gov (United States)

    Catarino, Rui; Ceddia, Graziano; Areal, Francisco J; Park, Julian

    2015-06-01

    The intensification of agriculture and the development of synthetic insecticides enabled worldwide grain production to more than double in the last third of the 20th century. However, the heavy dependence and, in some cases, overuse of insecticides has been responsible for negative environmental and ecological impacts across the globe, such as a reduction in biodiversity, insect resistance to insecticides, negative effects on nontarget species (e.g. natural enemies) and the development of secondary pests. The use of recombinant DNA technology to develop genetically engineered insect-resistant crops could mitigate many of the negative side effects of insecticides. One such genetic alteration enables crops to express toxic crystalline (Cry) proteins from the soil bacteria Bacillus thuringiensis (Bt). Despite the widespread adoption of Bt crops, there are still a range of unanswered questions concerning longer term agro-ecosystem interactions. For instance, insect species that are not susceptible to the expressed toxin can develop into secondary pests and cause significant damage to the crop. Here, we review the main causes surrounding secondary pest dynamics in Bt crops and the impact of such outbreaks. Regardless of the causes, if nonsusceptible secondary pest populations exceed economic thresholds, insecticide spraying could become the immediate solution at farmers' disposal, and the sustainable use of this genetic modification technology may be in jeopardy. Based on the literature, recommendations for future research are outlined that will help to improve the knowledge of the possible long-term ecological trophic interactions of employing this technology. PMID:25832330

  14. Field assessment of Bt cry1Ah corn pollen on the survival, development and behavior of Apis mellifera ligustica.

    Science.gov (United States)

    Dai, Ping-Li; Zhou, Wei; Zhang, Jie; Cui, Hong-Juan; Wang, Qiang; Jiang, Wei-Yu; Sun, Ji-Hu; Wu, Yan-Yan; Zhou, Ting

    2012-05-01

    Honeybees may be exposed to insecticidal proteins from transgenic plants via pollen. An assessment of the impact of such exposures on the honeybee is an essential part of the risk assessment process for transgenic Bacillus thuringiensis corn. A field trial was conducted to evaluate the effect of transgenic Bt cry1Ah corn on the honeybee Apis mellifera ligustica. Colonies of honeybees were moved to Bt or non-Bt corn fields during anthesis and then sampled to record their survival, development and behavior. No differences in immature stages, worker survival, bee body weight, hypopharyngeal gland weight, colony performance, foraging activity or olfactory learning abilities were detected between colonies that were placed in non-Bt corn fields and those placed in Bt corn fields. We conclude that cry1Ah corn carries no risk for the survival, development, colony performance or behavior of the honeybee A. mellifera ligustica. PMID:22364780

  15. Binding of Bt Cry toxins to lepidopteran midgut aminopeptidase N and the relationship between their interactions with Bt resistance%鳞翅目昆虫氨肽酶N与Bt毒素的结合及其与Bt抗性的关系

    Institute of Scientific and Technical Information of China (English)

    马文静; 韩兰芝; 尹新明; 曹广春; 苏丽娟

    2011-01-01

    随着Bt Cry作物在我国的广泛应用和推广,靶标害虫对其抗性风险已成为Bt Cry作物生态安全研究的重要内容.氨肽酶N(Aminopeptidase N,APN)是位于昆虫中肠刷状缘膜囊泡(Brush Border Membrane Vesicles,BBMV)上Bt Cry毒素重要的受体蛋白之一,它与Bt Cry毒素的结合能力决定了Bt Cry毒素的杀虫活性及昆虫对Bt抗性的产生.本文从APN的结构特征与分类、APN与Bt Cry毒素的结合特异性、结合位点、结合过程中的分子互作机制及APN变异导致昆虫抗性产生几方面系统综述了鳞翅目昆虫中肠Bt Cry受体蛋白-氨肽酶N与Bt Cry 毒素的结合及其与Bt抗性关系的研究进展.%With the wide application and popularization of Bt Cry crop, the resistance of target pests a-gainst Bt Cry crop has become the focus of studies on its ecological safety. Aminopeptidase N (APN) is one of Bt-toxin receptor proteins located in brush border membrane vesicles ( BBMV) of insect midgut. Its binding capability with Bt Cry toxin determines the toxin's insecticidal spectrum and insect Bt resistance. This paper systemically reviews the progress of researches on APN structural characteristics and classfication, the binding feature, binding sites and interactions mechanism of Bt Cry toxin and APN as well as Bt resistance resulting from APN mutations.

  16. High susceptibility of Bt maize to aphids enhances the performance of parasitoids of lepidopteran pests.

    Directory of Open Access Journals (Sweden)

    Cristina A Faria

    Full Text Available Concerns about possible undesired environmental effects of transgenic crops have prompted numerous evaluations of such crops. So-called Bt crops receive particular attention because they carry bacteria-derived genes coding for insecticidal proteins that might negatively affect non-target arthropods. Here we show a remarkable positive effect of Bt maize on the performance of the corn leaf aphid Rhopalosiphum maidis, which in turn enhanced the performance of parasitic wasps that feed on aphid honeydew. Within five out of six pairs that were evaluated, transgenic maize lines were significantly more susceptible to aphids than their near-isogenic equivalents, with the remaining pair being equally susceptible. The aphids feed from the phloem sieve element content and analyses of this sap in selected maize lines revealed marginally, but significantly higher amino acid levels in Bt maize, which might partially explain the observed increased aphid performance. Larger colony densities of aphids on Bt plants resulted in an increased production of honeydew that can be used as food by beneficial insects. Indeed, Cotesia marginiventris, a parasitoid of lepidopteran pests, lived longer and parasitized more pest caterpillars in the presence of aphid-infested Bt maize than in the presence of aphid-infested isogenic maize. Hence, depending on aphid pest thresholds, the observed increased susceptibility of Bt maize to aphids may be either a welcome or an undesirable side effect.

  17. Impacts of Bt crops on non-target organisms and insecticide use patterns

    Science.gov (United States)

    Bacillus thuringiensis (Bt), a bacterium capable of producing insecticidal proteins is ubiquitous in the environment, and the genes coding for these proteins are now becoming ubiquitous in major crop plants via recombinant DNA technology where they provide host plant resistance to major lepidopteran...

  18. Selection of Homozygous Cotton Lines Transformed with Two Insect-Resistant Genes

    Institute of Scientific and Technical Information of China (English)

    WU Jia-he; TIAN Ying-chuan; LUO Xiao-li; GUO Hong-nian; SHI Yue-jin; CHEN Xiao-ying; JIA Yan-tao; XIAO Juan-li; ZHANG Xian-long

    2003-01-01

    A plant expression vector containing a chimeric Bt29K gene coding for the activated Cry1Ac protein and the arrowhead proteinase inhibitior gene API-B were introduced into the cotton cultivar Jihe321 mediated by Agrobactertium tumefaciens. Based on the results of kanamycin resistant testing, PCR detection for both foreign genes and insect bioassay using Heliethis armigera, nine transgenic homozygous cotton lines with insect-resistance of more than 90% and better agronomic traits were bred through six generations from the original transgenic plants. Results from insect bioassay and sequence analysis of the PCR products of plants from some homozygous lines indicated that the chimeric Bt29K gene was stably inherited in these transgenic cotton lines. The main agronomic characters of these homozygous cotton lines, such as boll productivity and fibre strength, were better than that of the original cotton cv. Jihe321.

  19. A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

    Directory of Open Access Journals (Sweden)

    Fei Yang

    Full Text Available To counter the threat of insect resistance, Bacillus thuringiensis (Bt maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag, as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie. Cross-pollination in RIB caused a majority (>90% of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

  20. ISOLATION, CHARACTERIZATION OF PHYTASE PRODUCING BACILLUS SUBTILS BtRS2 FROM THE RHIZOSPHERE SOIL OF Bt COTTON FIELD

    OpenAIRE

    K. Usha Sri

    2013-01-01

    Soil samples of Bt Rhizosphere were collected from Bt cotton growing area of Andhra Pradesh, India and was used as a source material for isolation and screening of phytase producing bacteria. 19Bacteria were isolated from Bt Rhizosphere. Phytase enzyme activity of the cultures was screened on modified phytase solubulizing medium (MPSM). The result inferred that six isolates BtRS1 to BtRS6 were strongly positive in enzyme activity than six of other microorganisms while seven isolates were foun...

  1. Cannibalism of Helicoverpa zea (Lepidoptera: Noctuidae) from Bacillus thuringiensis (Bt) transgenic corn versus non-Bt corn.

    Science.gov (United States)

    Chilcutt, Charles F

    2006-06-01

    Because of the importance of cannibalism in population regulation of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in corn, Zea mays L., it is useful to understand the interactions between Bacillus thuringiensis (Bt) transgenic corn and cannibalism. To determine the effects of Bt corn on cannibalism in H. zea, pairs of the same or different instars were taken from Bt or non-Bt corn and placed on artificial diet in proximity. Cannibalism occurred in 91% of pairs and was approximately 7% greater for pairs of larvae reared from Bt transgenic corn (95%) than from non-Bt corn (88%). Also, first instar by first instar pairs had a lower rate of cannibalism than other pairs. Time until cannibalism was not different for larvae from Bt corn versus non-Bt corn. Pupation rate of cannibals and surviving victims was not different for pairs from Bt corn versus non-Bt corn. Finally, cannibalism increased pupation rate of cannibals from both Bt and non-Bt corn by approximately 23 and 12%, respectively, although the increases were not significant. Thus, negative effects of Bt on larvae were compensated by increased cannibalism in comparison with larvae reared on non-Bt corn, which increased larval survival to levels comparable with larvae reared on non-Bt plants.

  2. Impact of six transgenic Bacillus thuringiensis rice lines on four nontarget thrips species attacking rice panicles in the paddy field.

    Science.gov (United States)

    Akhtar, Z R; Tian, J C; Chen, Y; Fang, Q; Hu, C; Peng, Y F; Ye, G Y

    2013-02-01

    As a key component of ecological risk assessments, nontarget effects of Bacillus thuringiensis (Bt) rice have been tested under laboratory and field conditions for various organisms. A 2-yr field experiment was conducted to observe the nontarget effects of six transgenic rice lines (expressing the Cry1Ab or fused protein of Cry1Ab and Cry1Ac) on four nontarget thrips species including Frankliniella intonsa (Trybom), F. tenuicornis (Uzel), Haplothrips aculeatus (F.), and H. tritici (Kurd), as compared with their rice parental control lines. Two sampling methods including the beat plate and plastic bag method were used to monitor the population densities of the four thrips species for 2 yr. The results showed that the seasonal average densities of four tested thrips species in Bt rice plots were significantly lower than or very similar to those in the non-Bt rice plots depending on rice genotypes, sampling methods, and years. Among all six tested Bt rice lines, transgenic B1 and KMD2 lines suppressed the population of these tested thrips species the most. Our results indicate that the tested Bt rice lines are unlikely to result in high population pressure of thrips species in comparison with non-Bt rice. In some cases, Bt rice lines could significantly suppress thrips populations in the rice ecosystem. In addition, compatibility of Bt rice, with rice host plant resistance to nontarget sucking pests is also discussed within an overall integrated pest management program for rice. PMID:23339799

  3. Bacillus thuringiensis (Bt) transgenic crop: an environment friendly insect-pest management strategy.

    Science.gov (United States)

    Kumar, Suresh; Chandra, Amaresh; Pandey, K C

    2008-09-01

    Introduction of DDT (dichloro-diphenyl-trichloroethane) and following move towards indiscriminate use of synthetic chemical insecticides led to the contamination of water and food sources, poisoning of non-target beneficial insects and development of insect-pests resistant to the chemical insecticides. Increased public concems about the adverse environmental effects of indiscriminate use of chemical insecticides prompted search of altemative methods for insect-pest control. One of the promising alternatives has been the use of biological control agents. There is well-documented history of safe application of Bt (B. thuringiensis, a gram positive soil bacterium) as effective biopesticides and a number of reports of expression of delta-endotoxin gene(s) in crop plants are available. Only a few insecticidal sprays are required on Bt transgenic crops, which not only save cost and time, but also reduce health risks. Insects exhibit remarkable ability to develop resistance to different insecticidal compounds, which raises concern about the unsystematic use of Bt transgenic technology also. Though resistance to Bt products among insect species under field conditions has been rare, laboratory studies show that insects are capable of developing high levels of resistance to one ormore Cry proteins. Now it is generally agreed that 'high-dose/refuge strategy' is the most promising and practical approach to prolong the effectiveness of Bt toxins. Although manybiosafety concerns, ethical and moral issues exist, area under Bt transgenic crops is rapidly increasing and they are cultivated on more than 32 million hectares world over Even after reservation of European Union (EU) for acceptance of geneticaly modified (GM) crops, 6 out of 25 countries have already adopted Bt crops and many otherindustrial countries will adopt Bt transgenic crops in near future. While the modem biotechnology has been recognized to have a great potential for the promotion of human well-being, adoption

  4. Bacillus thuringiensis (Bt) transgenic crop: an environment friendly insect-pest management strategy.

    Science.gov (United States)

    Kumar, Suresh; Chandra, Amaresh; Pandey, K C

    2008-09-01

    Introduction of DDT (dichloro-diphenyl-trichloroethane) and following move towards indiscriminate use of synthetic chemical insecticides led to the contamination of water and food sources, poisoning of non-target beneficial insects and development of insect-pests resistant to the chemical insecticides. Increased public concems about the adverse environmental effects of indiscriminate use of chemical insecticides prompted search of altemative methods for insect-pest control. One of the promising alternatives has been the use of biological control agents. There is well-documented history of safe application of Bt (B. thuringiensis, a gram positive soil bacterium) as effective biopesticides and a number of reports of expression of delta-endotoxin gene(s) in crop plants are available. Only a few insecticidal sprays are required on Bt transgenic crops, which not only save cost and time, but also reduce health risks. Insects exhibit remarkable ability to develop resistance to different insecticidal compounds, which raises concern about the unsystematic use of Bt transgenic technology also. Though resistance to Bt products among insect species under field conditions has been rare, laboratory studies show that insects are capable of developing high levels of resistance to one ormore Cry proteins. Now it is generally agreed that 'high-dose/refuge strategy' is the most promising and practical approach to prolong the effectiveness of Bt toxins. Although manybiosafety concerns, ethical and moral issues exist, area under Bt transgenic crops is rapidly increasing and they are cultivated on more than 32 million hectares world over Even after reservation of European Union (EU) for acceptance of geneticaly modified (GM) crops, 6 out of 25 countries have already adopted Bt crops and many otherindustrial countries will adopt Bt transgenic crops in near future. While the modem biotechnology has been recognized to have a great potential for the promotion of human well-being, adoption

  5. Daxx Interacts With Phage ΦBT1 Integrase and Inhibits Its Recombination%Daxx与ΦBT1相互作用并抑制其重组活性

    Institute of Scientific and Technical Information of China (English)

    王臻臻; 王然; 李文娟; 薛京伦; 陈金中

    2013-01-01

    The bacterial phage ΦBT1 integrase is a promising tool due to its site-specific transgene character.It enriches the site-specific transgenic tools and provides the possibility for multiple site-specific transgenic manipulations.To improve its safety as a vector of gene therapy,it is necessary to investigate the potential interactions between ΦBT1 and proteins in mammalian host cells.Yeast mating and co-immunoprecipitation assay indicated that a tetrapeptide 433RFAL436 in ΦBT1 integrase was responsible for ΦBT1 and Daxx interaction.It was also demonstrated that over-expression of Daxx could reduce ΦBT1 mediated recombination rate in 293T cells by using ΦBT1 report system.It is the first time to identify a cellular protein interacting with ΦBT1 integrase and inhibiting its recombination efficiency.This result might be useful for improving the ΦBT1 integrase mediated transgene methods and directing the selection of target cells for ΦBT1 integrase.%噬菌体整合酶BT1因其具有可介导转基因位点特异性整合的能力而成为了基因治疗中一种有效的工具,它丰富了转基因载体的选择,并使得多位点特异性整合成为可能.为了能够更加安全有效地利用ΦBT1整合酶作为基因治疗载体,有必要了解ΦBT1整合酶与宿主细胞内蛋白质相互作用的情况.酵母配对实验与免疫共沉淀实验揭示了ΦBT1整合酶中4个氨基酸433RFAL436对整合酶与PML-NBs蛋白Daxx的结合起到了关键作用.通过进一步构建并利用ΦBT1整合酶哺乳动物细胞报告系统,证实过表达Daxx会抑制ΦBT1整合酶在293T细胞中的重组效率.以上结果表明,细胞内的蛋白质可以与ΦBT1整合酶发生相互作用并抑制其重组活性,对于改善ΦBT1整合酶介导的转基因操作以及选择ΦBT1整合酶靶细胞方面具有重要的参考意义.

  6. MORAL HAZARD AND BT CORN REFUGE

    OpenAIRE

    Mitchell, Paul D.; Zhu, En (John)

    2003-01-01

    Using a principal-agent model, we find the optimal subsidy contract that induces grower compliance with Bt corn refuge requirements for managing insect resistance when asymmetric information exists concerning grower behavior. The optimal contract balances the cost of monitoring and the benefit of reducing the likelihood of insect resistance.

  7. Incipient resistance of Helicoverpa punctigera to the Cry2Ab Bt toxin in Bollgard II cotton.

    Directory of Open Access Journals (Sweden)

    Sharon Downes

    Full Text Available Combinations of dissimilar insecticidal proteins ("pyramids" within transgenic plants are predicted to delay the evolution of pest resistance for significantly longer than crops expressing a single transgene. Field-evolved resistance to Bacillus thuringiensis (Bt transgenic crops has been reported for first generation, single-toxin varieties and the Cry1 class of proteins. Our five year data set shows a significant exponential increase in the frequency of alleles conferring Cry2Ab resistance in Australian field populations of Helicoverpa punctigera since the adoption of a second generation, two-toxin Bt cotton expressing this insecticidal protein. Furthermore, the frequency of cry2Ab resistance alleles in populations from cropping areas is 8-fold higher than that found for populations from non-cropping regions. This report of field evolved resistance to a protein in a dual-toxin Bt-crop has precisely fulfilled the intended function of monitoring for resistance; namely, to provide an early warning of increases in frequencies that may lead to potential failures of the transgenic technology. Furthermore, it demonstrates that pyramids are not 'bullet proof' and that rapid evolution to Bt toxins in the Cry2 class is possible.

  8. Soil microbial biomass and root growth in Bt and non-Bt cotton

    Science.gov (United States)

    Tan, D. K. Y.; Broughton, K.; Knox, O. G.; Hulugalle, N. R.

    2012-04-01

    The introduction of transgenic Bacillus thuringiensis (Bt) cotton (Gossypium hirsutum L.) has had a substantial impact on pest management in the cotton industry. While there has been substantial research done on the impact of Bt on the above-ground parts of the cotton plant, less is known about the effect of Bt genes on below ground growth of cotton and soil microbial biomass. The aim of this research was to test the hypothesis that Bt [Sicot 80 BRF (Bollgard II Roundup Ready Flex®)] and non-Bt [Sicot 80 RRF (Roundup Ready Flex®)] transgenic cotton varieties differ in root growth and root turnover, carbon indices and microbial biomass. A field experiment was conducted in Narrabri, north-western NSW. The experimental layout was a randomised block design and used minirhizotron and core break and root washing methods to measure cotton root growth and turnover during the 2008/09 season. Root growth in the surface 0-0.1 m of the soil was measured using the core break and root washing methods, and that in the 0.1 to 1 m depth was measured with a minirhizotron and an I-CAP image capture system. These measurements were used to calculate root length per unit area, root carbon added to the soil through intra-seasonal root death, carbon in roots remaining at the end of the season and root carbon potentially added to the soil. Microbial biomass was also measured using the ninhydrin reactive N method. Root length densities and length per unit area of non-Bt cotton were greater than Bt cotton. There were no differences in root turnover between Bt and non-Bt cotton at 0-1 m soil depth, indicating that soil organic carbon stocks may not be affected by cotton variety. Cotton variety did not have an effect on soil microbial biomass. The results indicate that while there are differences in root morphology between Bt and non-Bt cotton, these do not change the carbon turnover dynamics in the soil.

  9. Impact of corn earworm injury on yield of transgenic corn producing Bt toxins in the Carolinas.

    Science.gov (United States)

    Reay-Jones, Francis P F; Reisig, Dominic D

    2014-06-01

    Transgenic corn, Zea mays L., hybrids expressing insecticidal Cry proteins from Bacillus thuringiensis (Bt) and insecticide applications to suppress injury from Helicoverpa zea (Boddie) were evaluated in Florence, SC, and in Plymouth, NC, in 2012 and 2013. Based on kernel area injured, insecticide applications (chlorantraniliprole) every 3-4 d from R1 until H. zea had cycled out of corn reduced injury by 80-93% in Florence and 94-95% in Plymouth. Despite intensive applications of insecticide (13-18 per trial), limited injury still occurred in all treated plots in 2012, except in DKC 68-03 (Genuity VT Double PRO), based on kernels injured (both locations) and proportion of injured ears (Florence only). In 2013, ear injury was low in Plymouth, with no kernel injury in any insecticide-treated plots, except P1498R (non-Bt) and P1498YHR (Optimum Intrasect). Injury in Florence in 2013 did not occur in treated plots of DKC 68-04 (non-Bt), DKC 68-03 (Genuity VT Double PRO), and N785-3111 (Agrisure Viptera). Yields were not significantly affected by insecticide treatment and were not statistically different among near-isolines with and without Bt traits. Yields were not significantly associated with kernel injury based on regression analyses. The value of using Bt corn hybrids to manage H. zea is discussed.

  10. Practice Tests for the TOEFL iBT

    CERN Document Server

    Stirling, Bruce

    2012-01-01

    Practice Tests for the TOEFL iBT contains four TOEFL tests, with answer keys. Perfect for self-study and classrooms. Each TOEFL iBT Practice Test...* reflects the design of the official TOEFL internet-based test* tests academic English-language proficiency expected of university students in the United States, Canada, Australia, New Zealand, Ireland, Scotland and England* provides extra practice before you take the official TOEFL iBT* will help you identify those areas of academic English you need to improve for a higher TOEFL iBT score* will give you an unofficial, TOEFL iBT range score within

  11. Commercial production of transgenic Bt insect-resistant cotton varieties and the resistance management for bollworm (Helicoverpa armigera Hubner)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are currently three kinds of transgenic Bt insect-resistant cotton germplasm lines, Shanxi 94-24, Zhongxin 94 and R19, in China. They showed high resistance to the neonate larvae of bollworm (Helicoverpa armigera). Transgenic Bt insect-resistant cotton varieties or hybrids have been bred using the three kinds of germplasm lines as parents. Our researches reveal that there exist different expressions in resistant level at different developmental stages in the three categories of germplasm lines. When neonate larvae are fed with leaves of cotton plant at the seeding stage with less than 10 leaves on the main stem, the mortality of the neonate larvae is 100%, but the resistance level will decline at later season. When Bt gene has been transferred to the cotton genome, it can be steadily transferred to the progeny, the level of resistance to bollworm keeps fundamentally uniform. Such insects as tobacco budworm (Heliothis virencens) in laboratory directive selection are very apt to produce resistance to the Bt insecticidal crystal protein. From the present crop system of cotton region in the Yangtze and Yellow River Valleys, and the expression characteristic of transgenic Bt resistant cotton, we suggest that the resistance to toxin protein in bollworm is not apt to be produced if the transgenic Bt insect-resistant cotton varieties are released and grown in the regions except in the Xinjiang cotton region. The managing strategies to delay or retard the resistance are discussed.

  12. BT's adoption of customer centric design.

    Science.gov (United States)

    Chamberlain, Mark; Esquivel, Jacqueline; Miller, Fiona; Patmore, Jeff

    2015-01-01

    Between 2005 and 2010 BT underwent a major transformation from a company with a special section devoted to 'older and disabled consumers' to a company with an inclusive design strategy. The mainstreaming of these issues responded to a demand for better, more user-friendly communications products and growing awareness of the importance of previously marginalised consumer groups. It also took place alongside the development and publication of BS7000-6, a guide to inclusive design management. Based on several product design case studies, this paper reflects on how and why this transformation was seen as necessary for future success, and how the transformation was achieved. The evolution of BT's approach has continued since, but this paper looks back in time, and documents the transformation up to 2010 and reflects the state of the company in 2010 rather than at the time of publication.

  13. Genetic Basis of Cry1F-Resistance in a Laboratory Selected Asian Corn Borer Strain and Its Cross-Resistance to Other Bacillus thuringiensis Toxins.

    Science.gov (United States)

    Wang, Yueqin; Wang, Yidong; Wang, Zhenying; Bravo, Alejandra; Soberón, Mario; He, Kanglai

    2016-01-01

    The Asian corn borer (ACB), Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae), is the most destructive insect pest of corn in China. Susceptibility to the Cry1F toxin derived from Bacillus thuringiensis has been demonstrated for ACB, suggesting the potential for Cry1F inclusion as part of an insect pest management program. Insects can develop resistance to Cry toxins, which threatens the development and use of Bt formulations and Bt crops in the field. To determine possible resistance mechanisms to Cry1F, a Cry1F-resistant colony of ACB (ACB-FR) that exhibited more than 1700-fold resistance was established through selection experiments after 49 generations of selection under laboratory conditions. The ACB-FR strain showed moderate cross-resistance to Cry1Ab and Cry1Ac of 22.8- and 26.9-fold, respectively, marginally cross-resistance to Cry1Ah (3.7-fold), and no cross-resistance to Cry1Ie (0.6-fold). The bioassay responses of progeny from reciprocal F1 crosses to different Cry1 toxin concentrations indicated that the resistance trait to Cry1Ab, Cry1Ac and Cry1F has autosomal inheritance with no maternal effect or sex linked. The effective dominance (h) of F1 offspring was calculated at different concentrations of Cry1F, showing that h decreased as concentration of Cry1F increased. Finally, the analysis of actual and expected mortality of the progeny from a backcross (F1 × resistant strain) indicated that the inheritance of the resistance to Cry1F in ACB-FR was due to more than one locus. The present study provides an understanding of the genetic basis of Cry1F resistance in ACB-FR and also shows that pyramiding Cry1F with Cry1Ah or Cry1Ie could be used as a strategy to delay the development of ACB resistance to Bt proteins.

  14. Extrapolating non-target risk of Bt crops from laboratory to field

    OpenAIRE

    Jian J Duan; Lundgren, Jonathan G.; Naranjo, Steve; Marvier, Michelle

    2009-01-01

    The tiered approach to assessing ecological risk of insect-resistant transgenic crops assumes that lower tier laboratory studies, which expose surrogate non-target organisms to high doses of insecticidal proteins, can detect harmful effects that might be manifested in the field. To test this assumption, we performed meta-analyses comparing results for non-target invertebrates exposed to Bacillus thuringiensis (Bt) Cry proteins in laboratory studies with results derived from independent field ...

  15. Identification of relevant non-target organisms exposed to weevil-resistant Bt sweetpotato in Uganda

    OpenAIRE

    Rukarwa, R. J.; Mukasa, S. B.; Odongo, B.; Ssemakula, G.; Ghislain, M.

    2013-01-01

    Assessment of the impact of transgenic crops on non-target organisms (NTO) is a prerequisite to their release into the target environment for commercial use. Transgenic sweetpotato varieties expressing Cry proteins (Bt sweetpotato) are under development to provide effective protection against sweetpotato weevils (Coleoptera) which cause severe economic losses in sub-Saharan Africa. Like any other pest control technologies, genetically engineered crops expressing insecticidal proteins need to ...

  16. Detection and monitoring of insect resistance to transgenic Bt crops

    Institute of Scientific and Technical Information of China (English)

    FANGNENG HUANG

    2006-01-01

    Transgenic crops expressing Bacillus thuringiensis (Bt) endotoxins have become one of the most important tools for managing corn and cotton insect pests in the US and other countries. The widespread adoption of transgenic Bt crops could place a high degree of selection pressure on the target insect populations and accelerate development of resistance, raising concerns about the long-term durability of Bt plants as an effective pest management tool. Conservation of Bt susceptibility in insects has become one of the most active research areas in modern agriculture. One of the key factors for a successful Bt resistance management plan is to have a cost-effective monitoring system that can provide information on: (i) the initial Bt resistance allele frequencies at low levels in field insect populations; and (ii) early shifts in Bt resistance allele frequencies so that proactive measures for managing resistance can be deployed well before field control failures. Developing such a monitoring program has been difficult because: (i) resistance traits that occur at very low frequencies are hard to detect; (ii) many factors affect the sensitivity and accuracy of a Bt resistance monitoring program; and (iii) monitoring resistance is costly. Several novel methods for detecting Bt resistance alleles developed during the last decade have made a cost-effective monitoring system possible. Future studies should focus on how to improve and standardize the methodologies for insect sampling and Bt resistance detection.

  17. Exposure and nontarget effects of transgenic Bt corn debris in streams.

    Science.gov (United States)

    Jensen, Peter D; Dively, Galen P; Swan, Christopher M; Lamp, William O

    2010-04-01

    Corn (Zea mays L.) transformed with a gene from the bacterium Bacillus thuringiensis (Bt) comprises 49% of all corn in the United States. The input of senesced corn tissue expressing the Bt gene may impact stream-inhabiting invertebrates that process plant debris, especially trichopteran species related to the target group of lepidopteran pests. Our goal was to assess risk associated with transgenic corn debris entering streams. First, we show the input of corn tissue after harvest was extended over months in a stream. Second, using laboratory bioassays based on European corn borer [Ostrinia nubilalis (Hübner)], we found no bioactivity of Cry1Ab protein in senesced corn tissue after 2 wk of exposure to terrestrial or aquatic environments. Third, we show that Bt near-isolines modify growth and survivorship of some species of invertebrates. Of the four nontarget invertebrate species fed Bt near-isolines, growth of two closely related trichopterans was not negatively affected, whereas a tipulid crane fly exhibited reduced growth rates, and an isopod exhibited reduced growth and survivorship on the Cry1Ab near-isoline but not on the stacked Cry1Ab + Cry3Bb1 near-isoline. Because of lack of evidence of bioactivity of Bt after 2 wk and because of lack of nontarget effects on the stacked near-isoline, we suggest that tissue-mediated differences, and not the presence of the Cry1Ab protein, caused the different responses among the species. Overall, our results provide evidence that adverse effects to aquatic nontarget shredders involve complex interactions arising from plant genetics and environment that cannot be ascribed to the presence of Cry1Ab proteins.

  18. Multi-state trials of Bt sweet corn varieties for control of the corn earworm (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Shelton, A M; Olmstead, D L; Burkness, E C; Hutchison, W D; Dively, G; Welty, C; Sparks, A N

    2013-10-01

    Field tests in 2010-2011 were performed in New York, Minnesota, Maryland, Ohio, and Georgia to compare Bt sweet corn lines expressing Cry1A.105 + Cry2Ab2 and Cry1Ab with their non-Bt isolines, with and without the use of foliar insecticides. The primary insect pest in all locations during the trial years was Heliocoverpa zea (Boddie), which is becoming the most serious insect pest of sweet corn in the United States. At harvest, the ears were measured for marketability according to fresh market and processing standards. For fresh market and processing, least squares regression showed significant effects of protein expression, state, and insecticide frequency. There was a significant effect of year for fresh market but not for processing. The model also showed significant effects of H. zea per ear by protein expression. Sweet corn containing two genes (Cry1A.105 + Cry2Ab2) and a single gene (Cry1Ab) provided high marketability, and both Bt varieties significantly outperformed the traditional non-Bt isolines in nearly all cases regardless of insecticide application frequency. For pest suppression of H. zea, plants expressing Bt proteins consistently performed better than non-Bt isoline plants, even those sprayed at conventional insecticide frequencies. Where comparisons in the same state were made between Cry1A.105 + Cry2Ab2 and Cry1Ab plants for fresh market, the product expressing Cry1A.105 + Cry2Ab2 provided better protection and resulted in less variability in control. Overall, these results indicate Cry1A.105 + Cry2Ab2 and Cry1Ab plants are suitable for fresh market and processing corn production across a diversity of growing regions and years. Our results demonstrate that Bt sweet corn has the potential to significantly reduce the use of conventional insecticides against lepidopteran pests and, in turn, reduce occupational and environmental risks that arise from intensive insecticide use. PMID:24224259

  19. Consequences for Protaphorura armata (Collembola: Onychiuridae) following exposure to genetically modified Bacillus thuringiensis (Bt) maize and non-Bt maize

    International Nuclear Information System (INIS)

    Studies on the effect of genetically modified Bacillus thuringiensis (Bt) crops on true soil dwelling non-target arthropods are scarce. The objective of this study was to assess the influence of a 4-week exposure to two Bt maize varieties (Cry1Ab) Cascade and MEB307 on the collembolan Protaphorura armata. For comparison three non-Bt maize varieties, Rivaldo (isogenic to Cascade), Monumental (isogenic to MEB307) and DK242, and two control diets based on baker's yeast (uncontaminated and contaminated with Bt toxin Cry1Ab) were also tested. Due to a lower C:N ratio, individuals reared on yeast performed significantly better in all of the measured endpoints than those reared on maize. P. armata performed equally well when reared on two Bt and three non-Bt maize varieties. Although there were no negative effects of Bt maize in this experiment, we recommend future studies on Bt crops to focus on species interactions in long-term, multi-species experiments. - Protaphorura armata performed equally well when reared on two Bt and three non-Bt maize varieties

  20. Dispersal and movement behavior of neonate European corn borer (Lepidoptera: Crambidae) on non-Bt and transgenic Bt corn.

    Science.gov (United States)

    Goldstein, Jessica A; Mason, Charles E; Pesek, John

    2010-04-01

    Neonate movement and dispersal behavior of the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), were investigated under controlled conditions on Bacillus thuringiensis (Bt) and non-Bt corn, Zea mays L., to assess plant abandonment, dispersal from their natal plant, and silking behavior after Bt and non-Bt preexposure. With continuous airflow, neonates on a Bt corn plant for 24 h abandoned that plant 1.78 times more frequently than neonates on a non-Bt corn plant. Indirect evidence indicated that at least one third of the neonates were capable of ballooning within 24 h. In the greenhouse, some neonates were recovered after 24 h from plants 76 and 152 cm away that likely ballooned from their natal plant. After 1 h of preexposure on a Bt corn leaf, neonates placed on a new corn leaf and observed for 10 min began silking off of a new Bt leaf significantly sooner than a new non-Bt leaf. Results suggest that neonates are unable to detect Bt in the corn within 10 min but that they can detect it within the first hour.

  1. Consequences for Protaphorura armata (Collembola: Onychiuridae) following exposure to genetically modified Bacillus thuringiensis (Bt) maize and non-Bt maize

    Energy Technology Data Exchange (ETDEWEB)

    Heckmann, Lars-Henrik [National Environmental Research Institute, Department of Terrestrial Ecology, Vejlsovej 25, PO Box 314, DK-8600 Silkeborg (Denmark); Griffiths, Bryan S. [Scottish Crop Research Institute, Department of Soil Plant Dynamics, Invergowrie, Dundee DD2 5DA (United Kingdom); Caul, Sandra [Scottish Crop Research Institute, Department of Soil Plant Dynamics, Invergowrie, Dundee DD2 5DA (United Kingdom); Thompson, Jacqueline [Scottish Crop Research Institute, Department of Soil Plant Dynamics, Invergowrie, Dundee DD2 5DA (United Kingdom); Pusztai-Carey, Marianne [Case Western Reserve University, Cleveland, OH 44106 (United States); Moar, William J. [Auburn University, Department of Entomology and Plant Pathology, Auburn, AL 36849 (United States); Andersen, Mathias N. [Danish Institute of Agricultural Sciences, Research Centre Foulum, PO Box 50, DK-8830 Tjele (Denmark); Krogh, Paul Henning [National Environmental Research Institute, Department of Terrestrial Ecology, Vejlsovej 25, PO Box 314, DK-8600 Silkeborg (Denmark)]. E-mail: phk@dmu.dk

    2006-07-15

    Studies on the effect of genetically modified Bacillus thuringiensis (Bt) crops on true soil dwelling non-target arthropods are scarce. The objective of this study was to assess the influence of a 4-week exposure to two Bt maize varieties (Cry1Ab) Cascade and MEB307 on the collembolan Protaphorura armata. For comparison three non-Bt maize varieties, Rivaldo (isogenic to Cascade), Monumental (isogenic to MEB307) and DK242, and two control diets based on baker's yeast (uncontaminated and contaminated with Bt toxin Cry1Ab) were also tested. Due to a lower C:N ratio, individuals reared on yeast performed significantly better in all of the measured endpoints than those reared on maize. P. armata performed equally well when reared on two Bt and three non-Bt maize varieties. Although there were no negative effects of Bt maize in this experiment, we recommend future studies on Bt crops to focus on species interactions in long-term, multi-species experiments. - Protaphorura armata performed equally well when reared on two Bt and three non-Bt maize varieties.

  2. TMD factorization and evolution at large $b_T$

    Energy Technology Data Exchange (ETDEWEB)

    Collins, John [Pennsylvania State Univ., University Park, PA (United States); Rogers, Ted [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)

    2015-07-20

    In using transverse-momentum-dependent (TMD) parton densities and fragmentation functions, important non-perturbative information is at large transverse position $b_T$. This concerns both the TMD functions and their evolution. Fits to high energy data tend to predict too rapid evolution when extrapolated to low energies where larger values of $b_T$ dominate. I summarize a new analysis of the issues. It results in a proposal for much weaker $b_T$ dependence at large $b_T$ for the evolution kernel, while preserving the accuracy of the existing fits. The results are particularly important for using transverse-spin-dependent functions like the Sivers function.

  3. The development and status of Bt rice in China.

    Science.gov (United States)

    Li, Yunhe; Hallerman, Eric M; Liu, Qingsong; Wu, Kongming; Peng, Yufa

    2016-03-01

    Multiple lines of transgenic rice expressing insecticidal genes from the bacterium Bacillus thuringiensis (Bt) have been developed in China, posing the prospect of increases in production with decreased application of pesticides. We explore the issues facing adoption of Bt rice for commercial production in China. A body of safety assessment work on Bt rice has shown that Bt rice poses a negligible risk to the environment and that Bt rice products are as safe as non-Bt control rice products as food. China has a relatively well-developed regulatory system for risk assessment and management of genetically modified (GM) plants; however, decision-making regarding approval of commercial production has become politicized, and two Bt rice lines that otherwise were ready have not been allowed to enter the Chinese agricultural system. We predict that Chinese farmers would value the prospect of increased yield with decreased use of pesticide and would readily adopt production of Bt rice. That Bt rice lines may not be commercialized in the near future we attribute to social pressures, largely due to the low level of understanding and acceptance of GM crops by Chinese consumers. Hence, enhancing communication of GM crop science-related issues to the public is an important, unmet need. While the dynamics of each issue are particular to China, they typify those in many countries where adoption of GM crops has been not been rapid; hence, the assessment of these dynamics might inform resolution of these issues in other countries.

  4. The development and status of Bt rice in China.

    Science.gov (United States)

    Li, Yunhe; Hallerman, Eric M; Liu, Qingsong; Wu, Kongming; Peng, Yufa

    2016-03-01

    Multiple lines of transgenic rice expressing insecticidal genes from the bacterium Bacillus thuringiensis (Bt) have been developed in China, posing the prospect of increases in production with decreased application of pesticides. We explore the issues facing adoption of Bt rice for commercial production in China. A body of safety assessment work on Bt rice has shown that Bt rice poses a negligible risk to the environment and that Bt rice products are as safe as non-Bt control rice products as food. China has a relatively well-developed regulatory system for risk assessment and management of genetically modified (GM) plants; however, decision-making regarding approval of commercial production has become politicized, and two Bt rice lines that otherwise were ready have not been allowed to enter the Chinese agricultural system. We predict that Chinese farmers would value the prospect of increased yield with decreased use of pesticide and would readily adopt production of Bt rice. That Bt rice lines may not be commercialized in the near future we attribute to social pressures, largely due to the low level of understanding and acceptance of GM crops by Chinese consumers. Hence, enhancing communication of GM crop science-related issues to the public is an important, unmet need. While the dynamics of each issue are particular to China, they typify those in many countries where adoption of GM crops has been not been rapid; hence, the assessment of these dynamics might inform resolution of these issues in other countries. PMID:26369652

  5. TMD factorization and evolution at large $b_T$

    CERN Document Server

    Collins, John

    2015-01-01

    In using transverse-momentum-dependent (TMD) parton densities and fragmentation functions, important non-perturbative information is at large transverse position $b_T$. This concerns both the TMD functions and their evolution. Fits to high energy data tend to predict too rapid evolution when extrapolated to low energies where larger values of $b_T$ dominate. I summarize a new analysis of the issues. It results in a proposal for much weaker $b_T$ dependence at large $b_T$ for the evolution kernel, while preserving the accuracy of the existing fits. The results are particularly important for using transverse-spin-dependent functions like the Sivers function.

  6. Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae.

    Directory of Open Access Journals (Sweden)

    Harmen P Hendriksma

    Full Text Available The ecologically and economic important honey bee (Apis mellifera is a key non-target arthropod species in environmental risk assessment (ERA of genetically modified (GM crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.

  7. Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae.

    Science.gov (United States)

    Hendriksma, Harmen P; Härtel, Stephan; Steffan-Dewenter, Ingolf

    2011-01-01

    The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.

  8. Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae.

    Science.gov (United States)

    Hendriksma, Harmen P; Härtel, Stephan; Steffan-Dewenter, Ingolf

    2011-01-01

    The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops. PMID:22194811

  9. Effects of transgenic Bacillus thuringiensis maize grain on B. thuringiensis-susceptible Plodia interpunctella (Lepidoptera: Pyralidae).

    Science.gov (United States)

    Giles, K L; Hellmich, R L; Iverson, C T; Lewis, L C

    2000-06-01

    Percentage survivorship, developmental time, adult body length, and sex ratio of Plodia interpunctella (Hübner) reared on field-produced grain from sixteen cultivars of maize, Zea mays L., including several transgenic Bacillus thuringiensis (Bt) Berliner hybrids and selected non-Bt isolines, were evaluated under laboratory conditions. Compared with isolines, development was delayed and survivorship reduced for P. interpunctella reared on grain from transgenic hybrids with the CaMV/35s promoter that express Cry1Ab protein. Similarly, compared with non-Bt hybrids, a transgenic hybrid with the CaMV/35s promoter that expresses Cry9C protein delayed development, decreased survivorship, and caused reductions in adult body length of P. interpunctella. In contrast, no significant differences in P. interpunctella developmental times or survivorship were observed between transgenic hybrids with the PEPC promoter expressing Cry1Ab and their isolines. Additionally, developmental time, survivorship, and adult body length were similar between P. interpunctella reared on a transgenic hybrid with the CaMV/35s promoter expressing Cry1Ac and non-Bt hybrids. Our data demonstrate that transgenic Bt maize grain, especially grain from hybrids with the CaMV/35s promoter expressing Cry1Ab or Cry9C, can significantly affect B. thuringiensis-susceptible P. interpunctella populations up to 4 or 5 mo after harvest.

  10. Current trends in Bt crops and their fate on associated microbial community dynamics: a review.

    Science.gov (United States)

    Singh, Amit Kishore; Dubey, Suresh Kumar

    2016-05-01

    Cry protein expressing insect-resistant trait is mostly deployed to control major devastating pests and minimize reliance on the conventional pesticides. However, the ethical and environmental issues are the major constraints in their acceptance, and consequently, the cultivation of genetically modified (GM) crops has invited intense debate. Since root exudates of Bacillus thuringiensis (Bt) crops harbor the insecticidal protein, there is a growing concern about the release and accumulation of soil-adsorbed Cry proteins and their impact on non-target microorganisms and soil microbial processes. This review pertains to reports from the laboratory studies and field trials to assess the Bt toxin proteins in soil microbes and the processes determining the soil quality in conjunction with the existing hypothesis and molecular approaches to elucidate the risk posed by the GM crops. Ecological perturbations hinder the risk aspect of soil microbiota in response to GM crops. Therefore, extensive research based on in vivo and interpretation of results using high-throughput techniques such as NGS on risk assessment are imperative to evaluate the impact of Bt crops to resolve the controversy related to their commercialization. But more studies are needed on the risk associated with stacked traits. Such studies would strengthen our knowledge about the plant-microbe interactions. PMID:26560114

  11. Does Bt maize cultivation affect the non-target insect community in the agro ecosystem?

    Directory of Open Access Journals (Sweden)

    Daniela Chaves Resende

    2016-03-01

    Full Text Available ABSTRACT The cultivation of genetically modified crops in Brazil has led to the need to assess the impacts of this technology on non-target species. Under field conditions, the potential effect on insect biodiversity was evaluated by comparing a homogeneous corn field with conventional and transgenic maize, expressing different Bt proteins in seven counties of Minas Gerais, Brazil. The richness pattern of non-target insect species, secondary pests and natural enemies were observed. The results do not support the hypothesis that Bt protein affects insect biodiversity. The richness and diversity data of insects studied were dependent on the location and other factors, such as the use of insecticides, which may be a major factor where they are used.

  12. Cry Proteins from Bacillus thuringiensis Active against Diamondback Moth and Fall Armyworm.

    Science.gov (United States)

    Silva, M C; Siqueira, H A A; Silva, L M; Marques, E J; Barros, R

    2015-08-01

    Biopesticides based on Bacillus thuringiensis and genetically modified plants with genes from this bacterium have been used to control Plutella xylostella (L.) and Spodoptera frugiperda (J.E. Smith). However, the selection pressure imposed by these technologies may undermine the efficiency of this important alternative to synthetic insecticides. Toxins with different modes of action allow a satisfactory control of these insects. The purpose of this study was to characterize the protein and gene contents of 20 B. thuringiensis isolates from soil and insect samples collected in several areas of Northeast Brazil which are active against P. xylostella and S. frugiperda. Protein profiles were obtained by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Polymerase chain reaction assays were used to determine toxin genes present within bacterial isolates. The protein profile of the majority of the isolates produced bands of approximately 130 kDa, suggesting the presence of Cry1, Cry8 and Cry9 proteins. The gene content of the isolates of B. thuringiensis investigated showed different gene profiles. Isolates LIIT-4306 and LIIT-4311 were the most actives against both species, with LC50 of 0.03 and 0.02 × 10(8) spores mL(-1), respectively, for P. xylostella, and LC50 of 0.001 × 10(8) spores mL(-1) for S. frugiperda. These isolates carried the cry1, cry1Aa, cry1Ab, cry1Ac, cry1B, cry1C, cry1D, cry1F, cry2, cry2A, cry8, and cry9C genes. The obtained gene profiles showed great potential for the control of P. xylostella and S. frugiperda, primarily because of the presence of several cry1A genes, which are found in isolates of B. thuringiensis active against these insects. PMID:26070631

  13. A Meta-Analysis of Effects of Bt Crops on Honey Bees (Hymenoptera: Apidae)

    OpenAIRE

    Jian J Duan; Michelle Marvier; Joseph Huesing; Galen Dively; Zachary Y Huang

    2008-01-01

    BACKGROUND: Honey bees (Apis mellifera L.) are the most important pollinators of many agricultural crops worldwide and are a key test species used in the tiered safety assessment of genetically engineered insect-resistant crops. There is concern that widespread planting of these transgenic crops could harm honey bee populations. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a meta-analysis of 25 studies that independently assessed potential effects of Bt Cry proteins on honey bee survival (or ...

  14. 苦楝果实提取物对Bt-8010和Bt-7216的抑菌活性%Studies on the Bacteriostasis Activity of Azadirachtin Against Bt-8010 and Bt-7216

    Institute of Scientific and Technical Information of China (English)

    翟兴礼; 刘秀花

    2006-01-01

    将采摘的苦楝果实烘干、粉碎,以甲醇为溶剂,用超声波法提取苦楝果实的提取物,配成不同浓度的苦楝果实提取液,用于测定2种生物农药Bt-8010和Bt-7216的抑菌圈和抑菌率.结果表明:苦楝果实提取液浓度越高,其抑菌程度越大.其中,对Bt-7216的抑菌活性较大,Bt-8010次之.高浓度的苦楝提取物与生物农药(Bt)混用会降低Bt的药效.

  15. Call for Papers--Bt Research (ISSN 1925-1939)

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Bt Research (ISSN 1925-1939) is a new launched, open access and peer-reviewed journal that disseminates significant creative reviews and opinions or innovative research work in the area of Bacillus thuringiensis, including the isolation and identification of novel Bt strains, identification of novel Bt toxic genes and their functions, the insecticidal mechanism Bt toxics, Bt genetic engineering, transgenic Bt plants, the resistance mechanism of target-insect to Bt toxins, and the development of novel experimental methods and techniques for Bt Research.

  16. Immunotoxicological studies of genetically modified rice expressing PHA-E lectin or Bt toxin in Wistar rats

    DEFF Research Database (Denmark)

    Kroghsbo, Stine; Madsen, Charlotte Bernhard; Poulsen, Morten;

    2008-01-01

    As part of the SAFOTEST project the immunmodulating effect of Cry1Ab protein from Bacillus thuringiensis (Bt) and PHA-E lectin from kidney bean (Phaseolus vulgaris erythroagglutinin) was examined in 28- and 90-day feeding studies in Wistar rats. PHA-E lectin was chosen as positive control. Rats w...

  17. Bt maize and integrated pest management--a European perspective.

    Science.gov (United States)

    Meissle, Michael; Romeis, Jörg; Bigler, Franz

    2011-09-01

    The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include the risk of resistance evolution in target pest populations, risk of secondary pest outbreaks and increased administration to comply with licence agreements. Growers willing to plant Bt maize in the European Union (EU) often face the problem that authorisation is denied. Only one Bt maize transformation event (MON810) is currently authorised for commercial cultivation, and some national authorities have banned cultivation. Spain is the only EU member state where Bt maize adoption levels are currently delivering farm income gains near full potential levels. In an integrated pest management (IPM) context, Bt maize can be regarded as a preventive (host plant resistance) or a responsive pest control measure. In any case, Bt maize is a highly specific tool that efficiently controls the main pests and allows combination with other preventive or responsive measures to solve other agricultural problems including those with secondary pests.

  18. Bt-CoV HKU3 PCR/Sequencing Primers

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Rachel Graham ### Abstract This protocol details the primers and conditions used for forward and reverse PCR amplification and sequencing of Bt-CoV HKU3 genomes. ### Introduction This protocol details the steps, reagents, and conditions required to sequence Bt-CoV HKU3 genomes in the forward and reverse directions. The protocol begins with the RT-PCR step, assuming that BtCoV HKU3 RNA purified using a standard procedure (i.e., TRIzol extraction) has already been perfo...

  19. Bt-CoV HKU5 PCR/Sequencing Primers

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Rachel Graham ### Abstract This protocol details the primers and conditions used for forward and reverse PCR amplification and sequencing of Bt-CoV HKU5 genomes. ### Introduction This protocol details the steps, reagents, and conditions required to sequence Bt-CoV HKU5 genomes in the forward and reverse directions. The protocol begins with the RT-PCR step, assuming that BtCoV HKU5 RNA purified using a standard procedure (i.e., TRIzol extraction) has already been perfo...

  20. Can other host species of cotton bollworm be non-Bt refuges to prolong the effectiveness of Bt-cotton?

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The potential ecological risks of Bacillus thurigiensis (Bt) insecticides and Bt-crops have caused increasing concern since their commercial release in the field,among which pests' resistance to Bt-crops is the major ecological risk. Refuge tactic, which can produce sensitive populations, has proved to be a key and sound resistance management strategy in USA and Australia; however, no tactics have been performed in China where Bt-cotton is mostly planted with other host crops of cotton bollworm.Genetic variation and gene flow among different host populations of the cotton bollworm Helicoverpa armigera were analyzed using PCR fingerprinting method. The results show that maize and castor-oil plant, as well as cotton can take effect as refuges to prevent resistance of cotton bollworm to Bt-cotton, while peanut and sesame are not as suitable for planting with Bt-cotton as refuges in the field as low gene flow was detected among populations on peanut, sesame and Bt cotton.

  1. Suppressing Resistance to Bt Cotton with Sterile Insect Releases

    International Nuclear Information System (INIS)

    Genetically engineered crops that produce insecticidal toxins from Bacillus thuringiensis (Bt) are grown widely for pest control. However, insect adaptation can reduce the toxins' efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to provide susceptible insects to mate with resistant insects. Variable farmer compliance is one of the limitations of this approach. Here we report the benefits of an alternative strategy where sterile insects are released to mate with resistant insects and refuges are scarce or absent. Computer simulations show that this approach works in principle against pests with recessive or dominant inheritance of resistance. During a largescale, four-year field deployment of this strategy in Arizona, resistance of pink bollworm (Pectinophora gossypiella) to Bt cotton did not increase. A multitactic eradication program that included the release of sterile moths reduced pink bollworm abundance by >99%, while eliminating insecticide sprays against this key invasive pest. (author)

  2. Consumption of Bt maize pollen expressing Cry1Ab or Cry3Bb1 does not harm adult green Lacewings, Chrysoperla carnea (Neuroptera: Chrysopidae.

    Directory of Open Access Journals (Sweden)

    Yunhe Li

    Full Text Available Adults of the common green lacewing, Chrysoperla carnea (Stephens (Neuroptera: Chrysopidae, are prevalent pollen-consumers in maize fields. They are therefore exposed to insecticidal proteins expressed in the pollen of insect-resistant, genetically engineered maize varieties expressing Cry proteins derived from Bacillus thuringiensis (Bt. Laboratory experiments were conducted to evaluate the impact of Cry3Bb1 or Cry1Ab-expressing transgenic maize (MON 88017, Event Bt176 pollen on fitness parameters of adult C. carnea. Adults were fed pollen from Bt maize varieties or their corresponding near isolines together with sucrose solution for 28 days. Survival, pre-oviposition period, fecundity, fertility and dry weight were not different between Bt or non-Bt maize pollen treatments. In order to ensure that adults of C. carnea are not sensitive to the tested toxins independent from the plant background and to add certainty to the hazard assessment, adult C. carnea were fed with artificial diet containing purified Cry3Bb1 or Cry1Ab at about a 10 times higher concentration than in maize pollen. Artificial diet containing Galanthus nivalis agglutinin (GNA was included as a positive control. No differences were found in any life-table parameter between Cry protein containing diet treatments and control diet. However, the pre-oviposition period, daily and total fecundity and dry weight of C. carnea were significantly negatively affected by GNA-feeding. In both feeding assays, the stability and bioactivity of Cry proteins in the food sources as well as the uptake by C. carnea was confirmed. These results show that adults of C. carnea are not affected by Bt maize pollen and are not sensitive to Cry1Ab and Cry3Bb1 at concentrations exceeding the levels in pollen. Consequently, Bt maize pollen consumption will pose a negligible risk to adult C. carnea.

  3. Response of last instar Helicoverpa armigera larvae to Bt toxin ingestion: changes in the development and in the CYP6AE14, CYP6B2 and CYP9A12 gene expression.

    Directory of Open Access Journals (Sweden)

    Pilar Muñoz

    Full Text Available Bt crops are able to produce Cry proteins, which were originally present in Bacillus thuringiensis bacteria. Although Bt maize is very efficient against corn borers, Spanish crops are also attacked by the earworm H. armigera, which is less susceptible to Bt maize. Many mechanisms could be involved in this low susceptibility to the toxin, including the insect's metabolic resistance to toxins due to cytochrome P450 monooxygenases. This paper examines the response of last instar H. armigera larvae to feeding on a diet with Bt and non-Bt maize leaves in larval development and in the gene expression of three P450 cytochromes: CYP6AE14, CYP6B2 and CYP9A12. Larvae fed on sublethal amounts of the Bt toxin showed reduced food ingestion and reduced growth and weight, preventing most of them from achieving the critical weight and pupating; additionally, after feeding for one day on the Bt diet the larvae showed a slight increase in juvenile hormone II in the hemolymp. Larvae fed on the non-Bt diet showed the highest CYP6AE14, CYP6B2 and CYP9A12 expression one day after feeding on the non-Bt diet, and just two days later the expression decreased abruptly, a finding probably related to the developmental programme of the last instar. Moreover, although the response of P450 genes to plant allelochemicals and xenobiotics has been related in general to overexpression in the resistant insect, or induction of the genes when feeding takes place, the expression of the three genes studied was suppressed in the larvae feeding on the Bt toxin. The unexpected inhibitory effect of the Cry1Ab toxin in the P450 genes of H. armigera larvae should be thoroughly studied to determine whether this response is somehow related to the low susceptibility of the species to the Bt toxin.

  4. The Adoption of Bt-Maize - An Econometric Analysis

    OpenAIRE

    Consmuller, Nicola; Beckmann, Volker; Petrick, Martin

    2009-01-01

    In this study, we theoretically and empirically investigate the determinants of Bt maize adoption in German regions. Specifically, we ask how the regulatory framework, the farm structures as well as the socio-political environment of GM expansion in Germany have influenced regional adoption rates. Following a description of the relevant legal and economic framework in Germany, we develop theoretical hypotheses concerning regional variation in Bt-maize adoption and test them econometrically wi...

  5. Bt brinjal in India: a long way to go.

    Science.gov (United States)

    Kumar, Sandeep; Misra, Amita; Verma, Alok Kumar; Roy, Ruchi; Tripathi, Anurag; Ansari, Kausar M; Das, Mukul; Dwivedi, Premendra D

    2011-01-01

    Brinjal occupies the major proportion amongst all vegetable crops in India and is vulnerable to many diseases caused by insect-pests, fungus, bacteria and virus. Brinjal production is extensively affected by the insect brinjal fruit and shoot borer. Use of conventional chemical pesticides not only damage environment including the biotic and abiotic components but, also affect human health. Bt Brinjal was developed to combat brinjal fruit and shoot borer that has an advantage minimizing use of chemical pesticides. Extensive biosafety investigations, nutritional studies, substantial equivalence studies, relative toxicity and allergenicity assessment using animal models like Sprague Dawley rats, Brown Norway rats, rabbit, fish, chicken, goats, etc. revealed no significant differences between genetically modified brinjal and its native counterpart. Bt brinjal could effectively control the target pest and was found to be safe for environment and human health. In spite of all the scientific studies, release of Bt Brinjal has been put under moratorium. Indian government has constituted an expert committee to address this issue. In this review we have tried to explore the facts related to Bt Brinjal including its production, use of Bt toxin, use of chemical pesticides in controlling the FSB in native brinjal, along with perspective of public opinion and government initiatives. Key words: Bt Brinjal, agriculture, insecticides, GM foods, agrobacterium, transgenic crops. PMID:21865863

  6. Bt稻Cry1Ab蛋白的表达和降解及对采后季节土表灰橄榄长角跳虫发生的影响%Expression and degradation of Cry1Ab protein in Bt hybrid rice and its impacts on ground-dwelling Entomobrya griseoolivata occurrence in postharvest seasons

    Institute of Scientific and Technical Information of China (English)

    闫瑞红; 白耀宇; 程家安; 叶恭银

    2009-01-01

    To assess the potential ecological risk of Bt rice plant straw returning to field on nontarget ground-dwelling springtails in postharvest seasons, field expression and postharvest degradation of Cry1Ah protein in Bt hybrid rice Donglong (DL) were determined by using standard ELISA test kits of US EPA. At the same time, the individual numbers of the predominant springtail Entomobrya griseoolivata (Packard) (Collembola: Entomobryidae) were compared between DL and their non-parental control rice lines Xianyou 46 (XY) or Xinongyou 1 (XN) in postharvest paddy fields. Results showed that the Cry1Ab concentrations in the leaf blades, stems and roots of DL were 2.49-16.13 μg/g fresh weight in different developmental stages. The Cry1Ab could persist in DL plant litters for a long term after rice straw returning-to-field in postharvest seasons, and the Cry1Ab concentrations of the ground litters of stem and leaf, the rice plant stubbles and the root litters were 0.072, 0.074 and 0.033 μg/g dry weight at 132 day, respectively. The population densities of E. griseoolivata between DL and XY or XN fields were not significantly different, and the population dynamics of E. griseoolivata in DL field is similar to the two controls in most cases.%Bt水稻及其植株残体中的Bt杀虫蛋白对土壤跳虫具有潜在的生态风险.作者以Bt杂交稻东龙(DL)及非亲本对照汕优46(XY)和西农优1号(XN)为材料,采用ELISA法分析了DL各植株组织中Cry1Ab蛋白的田间表达和采后残留,并评价了采后季节DL植株秸秆还田对稻田土表跳虫发生量的影响.结果表明,在测定的各生长阶段,DL Cry1Ab在叶、茎和根系中的表达量为2.49~16.13 μg/g FW;在采后季节,DL各秸秆还田植株残体中的Cry1Ab可残留较长时间,在试验第132天地表茎叶、稻桩和根系中的残留量分别为0.072、0.074和0.033 μg/g DW;DL秸秆还田未对采后季节稻田土表发生量大的灰橄榄长角跳虫Entomobrya griseoolivata

  7. Comparative diversity of arthropods on Bt maize and non-Bt maize in two different cropping systems in South Africa.

    Science.gov (United States)

    Truter, J; Van Hamburg, H; Van Den Berg, J

    2014-02-01

    The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.

  8. Generation of insect-resistant and glyphosate-tolerant rice by introduction of a T-DNA containing two Bt insecticidal genes and an EPSPS gene

    Institute of Scientific and Technical Information of China (English)

    Qi-chao ZHAO; Ming-hong LIU; Xian-wen ZHANG; Chao-yang LIN; Qing ZHANG; Zhi-cheng SHEN‡

    2015-01-01

    题目:转Cry1Ac、Cry1Ig和EPSPS基因水稻及其抗虫、抗草甘膦活性鉴定  目的:获得具有高水平表达 Cry1Ac、Cry1Ig和 EPSPS基因并且具有抗虫、抗草甘膦活性的转基因水稻株。  创新点:Cry1Ig为新发现的苏云金杆菌(Bt)杀虫基因;Cry1Ig与 Cry1Ac共同使用有利于延缓害虫产生对Bt杀虫蛋白抗性。  方法:将Cry1Ac、Cry1Ig和EPSPS(G10)基因的表达框依次插入到同一转移 DNA(T-DNA)中,再将此 T-DNA 利用农杆菌介导法转化到水稻中。从转基因后代中,利用蛋白质印迹法(Western blot)、DNA印迹法(Southern blot)和热不对称交错聚合酶链式反应(TAIL-PCR)技术,筛选出能够高水平表达上述三个基因以及 T-DNA 单拷贝插入并且未发生明显插入突变的转化株。对于筛选到的转化株,利用 Western blot进一步分析 Cry1Ac、Cry1Ig和 G10基因的表达水平;使用酶联免疫吸附测定(ELISA)检测Cry1Ac的表达量;使用棉铃虫、二化螟和稻纵卷叶螟为对象,测定转基因水稻的抗虫活性;使用草甘膦喷施法,测定转基因水稻的抗草甘膦活性。最后,在大田试验中,考察转基因水稻与非转基因水稻的基本农艺性状,观察 T-DNA 的插入是否对转基因水稻的生长产生明显的影响。  结论:本实验最终获得具有高水平表达Cry1Ac、Cry1Ig和G10基因以及T-DNA单拷贝插入并且未引起明显变化的转化株 GAI-14。GAI-14对棉铃虫、二化螟、稻纵卷叶螟以及草甘膦均具有明显的抗性。田间试验表明 GAI-14在基本农艺性状上与非转基因水稻无明显差异。%Insect resistance and glyphosate tolerance have been two of the most important traits in the genetic improvement of various crops. In this study, two Bacil us thuringiensis (Bt) insecticidal genes, Cry1Ac and Cry1Ig, and a modified glyphosate-tolerant 5-enolpyruvylshikimate-3-phosphate

  9. Field-Evolved Mode 1 Resistance of the Fall Armyworm to Transgenic Cry1Fa-Expressing Corn Associated with Reduced Cry1Fa Toxin Binding and Midgut Alkaline Phosphatase Expression.

    Science.gov (United States)

    Jakka, Siva R K; Gong, Liang; Hasler, James; Banerjee, Rahul; Sheets, Joel J; Narva, Kenneth; Blanco, Carlos A; Jurat-Fuentes, Juan L

    2015-12-04

    Insecticidal protein genes from the bacterium Bacillus thuringiensis (Bt) are expressed by transgenic Bt crops (Bt crops) for effective and environmentally safe pest control. The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of Bt crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and Bt corn was withdrawn from the local market. In this study, we used a field-collected Cry1Fa corn-resistant strain (456) of S. frugiperda to identify the mechanism responsible for field-evolved resistance. Binding assays detected reduced Cry1Fa, Cry1Ab, and Cry1Ac but not Cry1Ca toxin binding to midgut brush border membrane vesicles (BBMV) from the larvae of strain 456 compared to that from the larvae of a susceptible (Ben) strain. This binding phenotype is descriptive of the mode 1 type of resistance to Bt toxins. A comparison of the transcript levels for putative Cry1 toxin receptor genes identified a significant downregulation (>90%) of a membrane-bound alkaline phosphatase (ALP), which translated to reduced ALP protein levels and a 75% reduction in ALP activity in BBMV from 456 compared to that of Ben larvae. We cloned and heterologously expressed this ALP from susceptible S. frugiperda larvae and demonstrated that it specifically binds with Cry1Fa toxin. This study provides a thorough mechanistic description of field-evolved resistance to a transgenic Bt crop and supports an association between resistance and reduced Cry1Fa toxin binding and levels of a putative Cry1Fa toxin receptor, ALP, in the midguts of S. frugiperda larvae.

  10. Field-Evolved Mode 1 Resistance of the Fall Armyworm to Transgenic Cry1Fa-Expressing Corn Associated with Reduced Cry1Fa Toxin Binding and Midgut Alkaline Phosphatase Expression.

    Science.gov (United States)

    Jakka, Siva R K; Gong, Liang; Hasler, James; Banerjee, Rahul; Sheets, Joel J; Narva, Kenneth; Blanco, Carlos A; Jurat-Fuentes, Juan L

    2016-02-01

    Insecticidal protein genes from the bacterium Bacillus thuringiensis (Bt) are expressed by transgenic Bt crops (Bt crops) for effective and environmentally safe pest control. The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of Bt crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and Bt corn was withdrawn from the local market. In this study, we used a field-collected Cry1Fa corn-resistant strain (456) of S. frugiperda to identify the mechanism responsible for field-evolved resistance. Binding assays detected reduced Cry1Fa, Cry1Ab, and Cry1Ac but not Cry1Ca toxin binding to midgut brush border membrane vesicles (BBMV) from the larvae of strain 456 compared to that from the larvae of a susceptible (Ben) strain. This binding phenotype is descriptive of the mode 1 type of resistance to Bt toxins. A comparison of the transcript levels for putative Cry1 toxin receptor genes identified a significant downregulation (>90%) of a membrane-bound alkaline phosphatase (ALP), which translated to reduced ALP protein levels and a 75% reduction in ALP activity in BBMV from 456 compared to that of Ben larvae. We cloned and heterologously expressed this ALP from susceptible S. frugiperda larvae and demonstrated that it specifically binds with Cry1Fa toxin. This study provides a thorough mechanistic description of field-evolved resistance to a transgenic Bt crop and supports an association between resistance and reduced Cry1Fa toxin binding and levels of a putative Cry1Fa toxin receptor, ALP, in the midguts of S. frugiperda larvae. PMID:26637593

  11. Ocorrência do ácaro fitófago Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae em cultivares de milho Bt Occurrence of the phytophagous mite Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae on Bt corn cultivars

    Directory of Open Access Journals (Sweden)

    Marcos Antônio Matiello Fadini

    2012-09-01

    Full Text Available O objetivo deste trabalho foi avaliar a ocorrência do microácaro-da-face-inferior-das-folhas-de-milho Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae em cultivares transgênicas de milho, contendo as proteínas Cry1F e Cry 1 A(b e milho não Bt. Durante o período de junho de 2010 a janeiro de 2011, foram coletadas, quinzenalmente, cinco amostras aleatórias de quatro folhas em talhões de milho Bt, contendo a proteína Cry 1F e Cry 1 A(b, e de milho não Bt em áreas experimentais da Embrapa Milho e Sorgo, em Sete Lagoas, MG. As amostras de folhas foram vistoriadas por 15 minutos na região da nervura central, em busca de adultos de C. tricholaenae. Foram registrados 2.930 indivíduos de C. tricholaenae, sendo que 1.114 no milho Bt Cry 1F, 753 em Cry 1 A(b e 1063 indivíduos em folhas das cultivares não Bt. As maiores abundâncias populacionais médias ocorreram nos meses de novembro e dezembro. Os fatores estágio fenológico das plantas e precipitação afetaram positivamente a abundância de C. tricholaenae. A abundância média do período de coleta de C. tricholaenae foi reduzida pela cultivar de milho contendo a proteína Cry 1 A(b. Esse é o primeiro registro de ácaros sobre cultivares de milho transgênico no Brasil.The objective of this study was to evaluate the occurrence of "microácaro-da-face-inferior-das-folhas-de-milho" Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae on transgenic cultivars of corn containing proteins Cry1F and Cry 1 A (b and non-Bt corn. During the period from June 2010 to January 2011 were collected, every two weeks, five random samples of four leaves in plots of Bt corn containing the protein Cry 1F and Cry 1 A (b and non-Bt corn in the experimental area of Embrapa Corn and Sorghum, Sete Lagoas, MG. The leaf samples were examined for 15 minutes in the central region of leaf in search of adult C. tricholaenae. We recorded 2930 individuals of C. tricholaenae, 1114 on Bt Cry 1F, 752 on Cry 1 A

  12. Effects of Exogenous Jasmonic Acid on Concentrations of Direct-Defense Chemicals and Expression of Related Genes in Bt(Bacillus thuringiensis)Corn(Zea mays)

    Institute of Scientific and Technical Information of China (English)

    FENG Yuan-jiao; WANG Jian-wu; LUO Shi-ming

    2007-01-01

    Bt corn is one of the top three large-scale commercialized transgenic crops around the world.It is increasingly clear that the complementary durable approaches for pest control,which combine the endogenous defense of the crop with the introduced foreign genes,are promising alternative strategies for pest resistance management and the next generation of insect-resistant transgenic crops.In the present study,we tested the inducible effects of exogenous jasmonic acid(JA) on direct-defense chemical content,Bt protein concentration,and related gene expression in the leaves of Bt corn cultivar 34B24 and non-Bt cultivar 34B23 by chemical analysis,ELISA,and RT-PCR.The results show that the expression of LOX,PR-2αMPI,and PR-1 genes in the treated leaf(the first leaf)was promoted by exogenous JA both in 34B24 and 34B23.As compared with the control,the concentration of DIMBOA in the treated leaf was significantly increased by 63 and 18% for 34B24 and 34B23,respectively.The total phenolic acid was also increased by 24 and 12% for both 34B24 and 34B23.The Bt protein content of 34B24 in the treated leaf was increased by 13% but decreased significantly by 27% in the second leaf.The induced response of 34B24 was in a systemic way and was much stronger than that of 34B23.Those findings indicated that there is a synergistic interaction between Bt gene and internally induced chemical defense system triggered by externally applied JA in Bt corn.

  13. Poly-β-hydroxybutyrate Metabolism Is Unrelated to the Sporulation and Parasporal Crystal Protein Formation in Bacillus thuringiensis.

    Science.gov (United States)

    Wang, Xun; Li, Zhou; Li, Xin; Qian, Hongliang; Cai, Xia; Li, Xinfeng; He, Jin

    2016-01-01

    Poly-3-hydroxybutyrate (PHB) is a natural polymer synthesized by many bacteria as a carbon-energy storage material. It was accumulated maximally prior to the spore formation but was degraded during the process of sporulation in Bacillus thuringiensis. Intriguingly, B. thuringiensis also accumulates large amounts of insecticidal crystal proteins (ICPs) during sporulation, which requires considerable input of carbon and energy sources. How PHB accumulation affects sporulation and ICP formation remains unclear to date. Intuitively, one would imagine that accumulated PHB provides the energy required for ICP formation. Yet our current data indicate that this is not the case. First, growth curves of the deletion mutants of phaC (encoding the PHB synthase) and phaZ (encoding the PHB depolymerase) were found to be similar to the parent strain BMB171; no difference in growth rate could be observed. In addition we further constructed the cry1Ac10 ICP gene overexpression strains of BMB171 (BMB171-cry), as well as its phaC and phaZ deletion mutants ΔphaC-cry and ΔphaZ-cry to compare their spore and ICP production rates. Again, not much change of ICP production was observed among these strains either. In fact, PHB was still degraded in most ΔphaZ-cry cells as observed by transmission electron microscopy. Together these results indicated that there is no direct association between the PHB accumulation and the sporulation and ICP formation in B. thuringiensis. Some other enzymes for PHB degradation or other energy source may be responsible for the sporulation and/or ICP formation in B. thuringiensis. PMID:27379025

  14. Poly-β-hydroxybutyrate Metabolism Is Unrelated to the Sporulation and Parasporal Crystal Protein Formation in Bacillus thuringiensis

    Science.gov (United States)

    Wang, Xun; Li, Zhou; Li, Xin; Qian, Hongliang; Cai, Xia; Li, Xinfeng; He, Jin

    2016-01-01

    Poly-3-hydroxybutyrate (PHB) is a natural polymer synthesized by many bacteria as a carbon-energy storage material. It was accumulated maximally prior to the spore formation but was degraded during the process of sporulation in Bacillus thuringiensis. Intriguingly, B. thuringiensis also accumulates large amounts of insecticidal crystal proteins (ICPs) during sporulation, which requires considerable input of carbon and energy sources. How PHB accumulation affects sporulation and ICP formation remains unclear to date. Intuitively, one would imagine that accumulated PHB provides the energy required for ICP formation. Yet our current data indicate that this is not the case. First, growth curves of the deletion mutants of phaC (encoding the PHB synthase) and phaZ (encoding the PHB depolymerase) were found to be similar to the parent strain BMB171; no difference in growth rate could be observed. In addition we further constructed the cry1Ac10 ICP gene overexpression strains of BMB171 (BMB171-cry), as well as its phaC and phaZ deletion mutants ΔphaC-cry and ΔphaZ-cry to compare their spore and ICP production rates. Again, not much change of ICP production was observed among these strains either. In fact, PHB was still degraded in most ΔphaZ-cry cells as observed by transmission electron microscopy. Together these results indicated that there is no direct association between the PHB accumulation and the sporulation and ICP formation in B. thuringiensis. Some other enzymes for PHB degradation or other energy source may be responsible for the sporulation and/or ICP formation in B. thuringiensis. PMID:27379025

  15. Poly-β-hydroxybutyrate Metabolism Is Unrelated to the Sporulation and Parasporal Crystal Protein Formation in Bacillus thuringiensis.

    Science.gov (United States)

    Wang, Xun; Li, Zhou; Li, Xin; Qian, Hongliang; Cai, Xia; Li, Xinfeng; He, Jin

    2016-01-01

    Poly-3-hydroxybutyrate (PHB) is a natural polymer synthesized by many bacteria as a carbon-energy storage material. It was accumulated maximally prior to the spore formation but was degraded during the process of sporulation in Bacillus thuringiensis. Intriguingly, B. thuringiensis also accumulates large amounts of insecticidal crystal proteins (ICPs) during sporulation, which requires considerable input of carbon and energy sources. How PHB accumulation affects sporulation and ICP formation remains unclear to date. Intuitively, one would imagine that accumulated PHB provides the energy required for ICP formation. Yet our current data indicate that this is not the case. First, growth curves of the deletion mutants of phaC (encoding the PHB synthase) and phaZ (encoding the PHB depolymerase) were found to be similar to the parent strain BMB171; no difference in growth rate could be observed. In addition we further constructed the cry1Ac10 ICP gene overexpression strains of BMB171 (BMB171-cry), as well as its phaC and phaZ deletion mutants ΔphaC-cry and ΔphaZ-cry to compare their spore and ICP production rates. Again, not much change of ICP production was observed among these strains either. In fact, PHB was still degraded in most ΔphaZ-cry cells as observed by transmission electron microscopy. Together these results indicated that there is no direct association between the PHB accumulation and the sporulation and ICP formation in B. thuringiensis. Some other enzymes for PHB degradation or other energy source may be responsible for the sporulation and/or ICP formation in B. thuringiensis.

  16. Proteomic Analysis of Bacillus thuringiensis Strain 4.0718 at Different Growth Phases

    Directory of Open Access Journals (Sweden)

    Xiaohui Li

    2012-01-01

    Full Text Available The growth process of Bacillus thuringiensis Bt4.0718 strain was studied using proteomic technologies. The proteins of Bt whole cells at three phases—middle vegetative, early sporulation, and late sporulation—were extracted with lysis buffer, followed with separation by 2-DE and identified by MALDI-TOF/TOF MS. Bioactive factors such as insecticidal crystal proteins (ICPs including Cry1Ac(3, Cry2Aa, and BTRX28, immune inhibitor (InhA, and InhA precursor were identified. InhA started to express at the middle vegetative phase, suggesting its contribution to the survival of Bt in the host body. At the early sporulation phase, ICPs started their expression. CotJC, OppA, ORF1, and SpoIVA related to the formation of crystals and spores were identified, the expression characteristics of which ensured the stable formation of crystals and spores. This study provides an important foundation for further exploration of the stable expression of ICPs, the smooth formation of crystals, and the construction of recombinant strains.

  17. Transgenic Bacillus thuringiensis (Bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart.

    Science.gov (United States)

    Li, Guangsheng; Wang, Yongmo; Liu, Biao; Zhang, Guoan

    2014-01-01

    Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt) have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt) significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems.

  18. Transgenic Bacillus thuringiensis (Bt rice is safer to aquatic ecosystems than its non-transgenic counterpart.

    Directory of Open Access Journals (Sweden)

    Guangsheng Li

    Full Text Available Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems.

  19. Scoring Strategies for the TOEFL iBT A Complete Guide

    CERN Document Server

    Stirling, Bruce

    2012-01-01

    TOEFL students all ask: How can I get a high TOEFL iBT score? Answer: Learn argument scoring strategies. Why? Because the TOEFL iBT recycles opinion-based and fact-based arguments for testing purposes from start to finish. In other words, the TOEFL iBT is all arguments. That's right, all arguments. If you want a high score, you need essential argument scoring strategies. That is what Scoring Strategies for the TOEFL iBT gives you, and more!. TEST-PROVEN STRATEGIES. Learn essential TOEFL iBT scoring strategies developed in American university classrooms and proven successful on the TOEFL iBT. R

  20. Isolation of Gossypol and Analysis of Phytochemicals in Seed Extract of Bt and Non-Bt Varieties of Cotton

    Directory of Open Access Journals (Sweden)

    R.Chandrashekar

    2013-05-01

    Full Text Available The purpose of this study was to isolate the gossypol (Phenolic compound and screening of phytochemical constituents from seed extract. During this study gossypol was extracted from cotton seeds and cotton seed cake using different organic solvents like acetone, ethanol, methanol, pet ether, chloroform and hot water and screened for phytochemical constituents. Analysis revealed the presence of phenols, glycosides, flavonoids, and steroids. Specific tests were conducted for each group of the phytochemicals. Among the extracts tested polar solvents like acetone, ethanol, methanol extracts showed more phytochemicals than others followed by pet ether, hot water, chloroform. The phytochemicals like saponins, flavonoids, tri-terpenoids, and tannins were not found in seed extract, specifically showed phenols with more quantity in polar solvent extract like acetone, ethanol and methanol cardiac glycosides and steroids are observed in both polar and non-polar solvent of seed extracts. Similar kind of compounds are present in Bt and non-Bt but the appearance of test coloration of seed extracts predicted as is slightly darker for Bt variety. This could be due to more amount of the component may be present in Bt cotton seed extract than non-Bt cotton seed extract. The compound Gossypol was detected in extracts by applying Chromatographic technique as well as chemical tests with antimony chloride (SbCl3, and stannic chloride (SnCl3 and leadacetate (Pb(CH3COO2 . Spectrophotometric techniques were also employed for quantitative analysis by measuring absorbance of samples at wavelength of 290nm.

  1. Isolation and Characterization of Gut Bacterial Proteases Involved in Inducing Pathogenicity of Bacillus thuringiensis Toxin in Cotton Bollworm, Helicoverpa armigera

    Science.gov (United States)

    Regode, Visweshwar; Kuruba, Sreeramulu; Mohammad, Akbar S.; Sharma, Hari C.

    2016-01-01

    Bacillus thuringiensis toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac) to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation toward pro-Cry1Ac. Among 12 gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2, and IVS3) were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2, and IVS3 isolates were purified to 11.90-, 15.50-, and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40°C. Maximum inhibition of total proteolytic activity was exerted by phenylmethane sulfonyl fluoride followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65, and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity toward H. armigera. The gut bacterial isolates IVS1, IVS2, and IVS3 showed homology with B. thuringiensis (CP003763.1), Vibrio fischeri (CP000020.2), and Escherichia coli (CP011342.1), respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of B. thuringiensis protoxin and play a major role in inducing pathogenicity of B. thuringiensis toxins in H. armigera. PMID:27766093

  2. Hepatic gene mutations induced in Big Blue rats by both the potent rat liver azo-carcinogen 6BT and its reported noncarcinogenic analogue 5BT.

    Science.gov (United States)

    Fletcher, K; Soames, A R; Tinwell, H; Lefevre, P A; Ashby, J

    1999-01-01

    The potent rat liver carcinogen 6-p-dimethylaminophenylazobenzthiazole (6BT) and its reported noncarcinogenic analogue 5-p-dimethylaminophenylazobenzthiazole (5BT; evaluated for carcinogenicity under the similar limited bioassay conditions used for 6BT) have been studied in order to seek an explanation for their different carcinogenic activities. Both compounds act as DNA-damaging agents to the rat liver, and both have now been shown to induce lacI (-) gene mutations in the liver of Big Blue(trade mark) transgenic rats. Both compounds were mutagenic following ten daily gavage doses or following administration in diet for 10 days. Neither chemical induced cell proliferation in the liver following repeat gavage administrations. In contrast, dietary administration of 6BT, and to a lesser extent of 5BT, induced hepatic cell proliferation. The carcinogen 6BT, but not the noncarcinogen 5BT, caused proliferation of oval stem cells in the livers by both routes of administration. It is possible that mutations induced in oval cells by 6BT are responsible for its potent carcinogenicity, and that the comparative absence of these cells in 5BT-treated livers may account for the carcinogenic inactivity of 5BT. Equally, the proliferation of the oval cells may reflect changes in liver homeostasis associated with the liver toxicity observed at the dose level of 6BT used (which was, nonetheless, the dose level used in the positive cancer bioassays). It is concluded that the new data presented cannot explain the differing carcinogenic activities of 5BT and 6BT, and that the reported noncarcinogen 5BT may also be carcinogenic when adequately assessed for this activity.

  3. Effects of Resistance to Bt Cotton on Diapause in the Pink Bollworm, Pectinophora gossypiella

    Science.gov (United States)

    Carrière, Yves; Ellers-Kirk, Christa; Biggs, Robert W.; Sims, Maria A.; Dennehy, Timothy J.; Tabashnik, Bruce E.

    2007-01-01

    Fitness costs associated with resistance to Bacillus thuringiensis (Bt) crops are expected to delay the evolution of resistance. In a previous study where pink bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae), larvae overwintered in outdoor insectaries, individuals from Bt-resistant strains had lower survival than individuals from Bt-susceptible strains or F1 progeny from crosses between resistant and susceptible adults. To investigate the physiological basis of such recessive cost, diapause duration was experimentally manipulated in the laboratory. Compared to a Bt-susceptible strain and F1 progeny, we hypothesized that Bt-resistant strains could exhibit a lower propensity or intensity of diapause, faster weight loss during overwintering, lower initial weight of diapausing larvae, and reduced longevity of moths emerging from diapause. Results were as expected for initial weight of diapausing larvae and longevity of overwintered male moths or female moths remaining in diapause for a short period. However, a higher diapause induction and intensity and slower weight loss occurred in F1 progeny and Bt-resistant strains than in a Bt-susceptible strain. Moreover, F1 progeny had greater overwintering survival than the Bt-resistant and Bt-susceptible strains, and F1 female moths had the greatest longevity after sustaining long diapausing periods. All of these unexpected results may be explained by pleiotropic effects of resistance to Bt cotton that increased the strength of diapause in the F1 progeny and Bt-resistant strains. Incomplete resistance was reflected in disadvantages suffered by Bt-resistant individuals feeding on a Bt diet instead of a non-Bt diet, including lower diapause propensity, lower diapause intensity and reduced longevity of overwintered male moths. While this study suggests that the evolution of resistance to Bt cotton and feeding on a Bt diet in Bt-resistant individuals have pervasive effects on several traits associated with diapause

  4. In situ degrability of dry matter of sheep fed with corn silage with or without Bt gene

    OpenAIRE

    Camila Memari Trava; Mauro Sartori Bueno; Geraldo Balieiro

    2012-01-01

    Silage corn is a food widely used, composing the bulk of feed for ruminants, because its present high nutritional value. Since the release by CNTBio seeds of modified genetically corn, many of it began to use transgenic silage corn, which was inserted into genetic code the Bt (Bacillus thuringiensis) gene that expresses a toxic protein to caterpillar pests of corn, so occurs the reduction of production costs and pesticide use. Due to rapid expansion of transgenic maize and your wide use in an...

  5. Breeding and Characterization of a New Rice Restorer Line Containing Bt Gene

    Institute of Scientific and Technical Information of China (English)

    GAO Fang-yuan; LU Xian-jun; HE Shu-lin; CHEN Xiao-juan; LU Dai-hua; SUN Shu-xia; LI Zhi-hua; LIU Guang-chun; ZHANG Yi-zheng; REN Guang-jun

    2009-01-01

    Bt5198, a new rice restorer line containing Bt gene, was developed from the cross and backcross of the elite restorer line Chenghui 177 with Bt Minghui 63, a transgenic Bt restorer line. The inbred lines were evaluated using PCR amplification, test paper evaluation, insect resistance evaluation in both the laboratory and paddy fields, nursery evaluation of rice blast resistance and pedigree selection of agronomic traits. Larval mortalities on Bt5198 and Bt Minghui 63 were 100% when rice culms were inoculated with the eggs of the striped stem borer (SSB) in the laboratory. Bt5198 was highly resistant against SSB and the yellow stem borer (YSB) under field conditions. The F1 hybrids derived from Bt5198 and four cytoplasmic male sterile (CMS) lines were also highly resistant to SSB and YSB and had a significant heterosis. Two-year evaluation of rice blast resistance confirmed that the resistance levels of Bt5198 to leaf blast and neck blast were similar to those of Chenghui 177 and significantly better than those of Bt Minghui 63. Seed germination ability and pollen yield of Bt5198 were similar with Chenghui 177, suggesting that the introduction of the Bt gene into the new restorer line had no significant effects on seed vitality or the yield of seed production. To identify the presence of the Bt gene, it was effective to combine test paper examination with the evaluation of insect-resistance, both in the laboratory and under field conditions.

  6. Apparent digestibility coefficients and consumption of corn silage with and without Bt gene in sheep

    Directory of Open Access Journals (Sweden)

    Camila Memari Trava

    2012-12-01

    Full Text Available Corn silage is the most important preserved food for ruminants. The transgenic corn was inserted into the genetic code Bt gene (Bacillus thuringiensis that expresses a toxic protein to caterpillars pests of maize, reducing production costs. To evaluate the varieties of plant corn silage DKB and AG with or without the Bt gene on the voluntary intake of DM (g/day and apparent digestibility coefficients (CDA of nutrients in sheep, the experiment was conducted at the Institute of Animal Science Nova Odessa-SP. Were used 20 sheep and the experimental design was randomized blocks in scheme factorial type 2x2 (two varieties of plant corn to silage, with the presence or absence of Bt gene, with five animals per treatment. These animals were housed in metabolism cages, with collector and separator feces and urine for 21 days, comprising 8 days for diet adaptation and 7 days for determination of intake, followed by 6 days of collection of feces, to measure DMI (g/day, CDA DM, CP and NDF. Samples of feed offered, leftovers and feces were identified and placed in a circulating air oven maintained at 55°C to constant weight. The analyses were performed in Bromatological Analysis Laboratory of the Institute of Animal Science. To CTMS (g/day was interaction effect (p<0.05 than in the variety AG (779.36 was greater than DKB (637.52, because the DM content of the sheet AG (31.09 was superior to DKB (29.17. The AG (779.36 was higher than your counterpart isogenic without the gene (575.15 p<0.05. The DKB without the gene (637.52 did not differ (p>0.05 from your counterpart DKBBt with the gene (590.78. The lowest total DM intake in g/day was observed for varieties with Bt gene insertion (genetically modified organism - GMO and a possible explanation is the higher value of NDF in the silages of variety with the Bt gene in relation to their isogenic counterparts without the gene. The CDA, DM and NDF no had interaction effect between varieties factors and GMO (p>0

  7. Three toxins, two receptors, one mechanism: Mode of action of Cry1A toxins from Bacillus thuringiensis in Heliothis virescens.

    Science.gov (United States)

    Bretschneider, Anne; Heckel, David G; Pauchet, Yannick

    2016-09-01

    Insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) are highly active against Lepidoptera. However, field-evolved resistance to Bt toxins is on the rise. The 12-cadherin domain protein HevCaLP and the ABC transporter HevABCC2 are both genetically linked to Cry toxin resistance in Heliothis virescens. We investigated their interaction using stably expressing non-lytic clonal Sf9 cell lines expressing either protein or both together. Untransfected Sf9 cells are innately sensitive to Cry1Ca toxin, but not to Cry1A toxins; and quantitative PCR revealed negligible expression of genes involved in Cry1A toxicity such as cadherin, ABCC2, alkaline phosphatase (ALP) and aminopeptidase N (APN). Cry1Aa, Cry1Ab or Cry1Ac caused swelling of Sf9 cells expressing HevABCC2, and caused faster swelling, lysis and up to 86% mortality in cells expressing both proteins. No such effect was observed in control Sf9 cells or in cells expressing only HevCaLP. The results of a mixing experiment demonstrated that both proteins need to be expressed within the same cell for high cytotoxicity, and suggest a novel role for HevCaLP. Binding assays showed that the toxin-receptor interaction is specific. Our findings confirm that HevABCC2 is the central target in Cry1A toxin mode of action, and that HevCaLP plays a supporting role in increasing Cry1A toxicity.

  8. Three toxins, two receptors, one mechanism: Mode of action of Cry1A toxins from Bacillus thuringiensis in Heliothis virescens.

    Science.gov (United States)

    Bretschneider, Anne; Heckel, David G; Pauchet, Yannick

    2016-09-01

    Insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) are highly active against Lepidoptera. However, field-evolved resistance to Bt toxins is on the rise. The 12-cadherin domain protein HevCaLP and the ABC transporter HevABCC2 are both genetically linked to Cry toxin resistance in Heliothis virescens. We investigated their interaction using stably expressing non-lytic clonal Sf9 cell lines expressing either protein or both together. Untransfected Sf9 cells are innately sensitive to Cry1Ca toxin, but not to Cry1A toxins; and quantitative PCR revealed negligible expression of genes involved in Cry1A toxicity such as cadherin, ABCC2, alkaline phosphatase (ALP) and aminopeptidase N (APN). Cry1Aa, Cry1Ab or Cry1Ac caused swelling of Sf9 cells expressing HevABCC2, and caused faster swelling, lysis and up to 86% mortality in cells expressing both proteins. No such effect was observed in control Sf9 cells or in cells expressing only HevCaLP. The results of a mixing experiment demonstrated that both proteins need to be expressed within the same cell for high cytotoxicity, and suggest a novel role for HevCaLP. Binding assays showed that the toxin-receptor interaction is specific. Our findings confirm that HevABCC2 is the central target in Cry1A toxin mode of action, and that HevCaLP plays a supporting role in increasing Cry1A toxicity. PMID:27456115

  9. Bt Sweet Corn: What Is It and Why Should We Use It?

    OpenAIRE

    Barlow, Vonny M.; Kuhar, Thomas Patrick, 1969-; Speese, III, John

    2009-01-01

    This publication reviews Transgenic Bt sweet corn hybrids which are a genetically modified organism (GMO) that are the result of combining commercially available sweet corn varieties with genes from a naturally occurring soil bacterium called Bacillus thuringiensis Berliner or Bt.

  10. Susceptibility of Ostrinia furnacalis to Bacillus thuringiensis and Bt Corn Under Long-Term Laboratory Selection

    Institute of Scientific and Technical Information of China (English)

    WEN Li-ping; HE Kang-lai; WANG Zhen-ying; ZHOU Da-rong; BAI Shu-xiong

    2005-01-01

    The susceptibility of the Asian corn borer, Ostrinia furnacalis to Bacillus thuringiensis (Bt) formulation and Bt corn was evaluated using insect bioassays for 6 years. Four strains of O. furnacalis were developed by laboratory selection from the laboratory strain reared on a non-agar semi-artificial diet. The RR-1 strain was exposed to a commercial formulation of B. thuringiensis subsp. kurstaki (Btk) incorporated into the artificial diet, the RR-2 strain was exposed to Bt corn (MON810)tissue incorporated into the diet, and the SS-1 and SS-2 strains were reared on the standard diet with or without non-Bt corn tissues material. Decreasing susceptibility of O. furnacalis to Bt and to Bt corn were found in each selected strain although the ED50 and larval weight fluctuated from generation to generation. The resistance of Bt-exposed strain (RR-1)to Btk increased 48-fold by generation 39; the Bt corn-exposed strain (RR-2) increased its resistance 37-fold to Btk by generation 24. No larvae of SS-1 survived when they were exposed to the leaves of Bt corn, Bt1 1 and MON810. However,2-54% of the RR-1 (generation 46) and RR-2 (generation 20) larvae survived a 3 day-exposure to the leaves of Bt1 1 and MON810. The survival of both selected strains on Bt corn silk increased by 10-69%, and the larval weights after many generations selection were increased by 15-22% compared with the unselected susceptible strain. The young larvae were much more susceptible to Bt than older larvae. The highest mortality occurred when the larvae were exposed to Bt at the neonate stage. All of the results suggested that ACB could not only develop resistance to Bt preparation but also to Bt corn. Bt had significant effects on the growth and development of Asian corn borer than on the larval mortality. In order to maintain the long-term effectiveness of Bt pesticide and Bt corn, the resistance management should pay much attention to the larvae that may have opportunities to grow and developed on non-Bt

  11. Regulatory considerations surrounding the deployment of Bt-expressing cowpea in Africa: report of the deliberations of an expert panel.

    Science.gov (United States)

    Huesing, Joseph; Romeis, Jörg; Ellstrand, Norman; Raybould, Alan; Hellmich, Richard; Wolt, Jeff; Ehlers, Jeff; Dabiré, Clémentine; Fatokun, Christian; Hokanson, Karen; Ishiyaku, Mohammad F; Margam, Venu; Obokoh, Nompumelelo; Mignouna, Jacob; Nangayo, Francis; Ouedraogo, Jeremy; Pasquet, Rémy; Pittendrigh, Barry; Schaal, Barbara; Stein, Jeff; Tamò, Manuele; Murdock, Larry

    2011-01-01

    Cowpea (Vigna unguiculata spp unguiculata) is adapted to the drier agro-ecological zones of West Africa where it is a major source of dietary protein and widely used as a fodder crop. Improving the productivity of cowpea can enhance food availability and security in West Africa. Insect predation--predominately from the legume pod borer (Maruca vitrata), flower thrips (Megalurothrips sjostedti) and a complex of pod-sucking bugs (e.g., Clavigralla spp)--is a major yield-limiting factor in West African cowpea production. Dramatic increases in yield are shown when M. vitrata is controlled with insecticides. However, availability, costs, and safety considerations limit pesticides as a viable option for boosting cowpea production. Development of Bt-cowpea through genetic modification (GM) to control the legume pod borer is a promising approach to cowpea improvement. Cowpea expressing the lepidopteran-active Cry1Ab protein from Bacillus thuringiensis is being developed as a first generation Bt-cowpea crop for West Africa. Appropriate stewardship of Bt-cowpea to assure its sustainability under West African conditions is critical to its successful development. A first step in this process is an environmental risk assessment to determine the likelihood and magnitude of adverse effects of the Cry1Ab protein on key environmental protection goals in West Africa. Here we describe the results of an expert panel convened in 2009 to develop the problem formulation phase for Bt-cowpea and to address specific issues around gene flow, non-target arthropods, and insect resistance management.

  12. Identification of Glyceraldehyde-3-phosphate dehydrogenase (GAPDH as a binding protein for a 68-kDa Bacillus thuringiensis parasporal protein cytotoxic against leukaemic cells

    Directory of Open Access Journals (Sweden)

    Nadarajah Vishna

    2010-11-01

    Full Text Available Abstract Background Bacillus thuringiensis (Bt, an ubiquitous gram-positive spore-forming bacterium forms parasporal proteins during the stationary phase of its growth. Recent findings of selective human cancer cell-killing activity in non-insecticidal Bt isolates resulted in a new category of Bt parasporal protein called parasporin. However, little is known about the receptor molecules that bind parasporins and the mechanism of anti-cancer activity. A Malaysian Bt isolate, designated Bt18 produces parasporal protein that exhibit preferential cytotoxic activity for human leukaemic T cells (CEM-SS but is non-cytotoxic to normal T cells or other cancer cell lines such as human cervical cancer (HeLa, human breast cancer (MCF-7 and colon cancer (HT-29 suggesting properties similar to parasporin. In this study we aim to identify the binding protein for Bt18 in human leukaemic T cells. Methods Bt18 parasporal protein was separated using Mono Q anion exchange column attached to a HPLC system and antibody was raised against the purified 68-kDa parasporal protein. Receptor binding assay was used to detect the binding protein for Bt18 parasporal protein in CEM-SS cells and the identified protein was sent for N-terminal sequencing. NCBI protein BLAST was used to analyse the protein sequence. Double immunofluorescence staining techniques was applied to localise Bt18 and binding protein on CEM-SS cell. Results Anion exchange separation of Bt18 parasporal protein yielded a 68-kDa parasporal protein with specific cytotoxic activity. Polyclonal IgG (anti-Bt18 for the 68-kDa parasporal protein was successfully raised and purified. Receptor binding assay showed that Bt18 parasporal protein bound to a 36-kDa protein from the CEM-SS cells lysate. N-terminal amino acid sequence of the 36-kDa protein was GKVKVGVNGFGRIGG. NCBI protein BLAST revealed that the binding protein was Glyceraldehyde-3-phosphate dehydrogenase (GAPDH. Double immunofluorescence staining showed

  13. SNS ønsker kommentarer om oplysninger fra Syngenta Seeds vedr forurening med Bt10 i Bt11-majsen ændrer konklusionerne i risikovurderingen. Zea mays (Bt11) . Supplerende informationer om Bt11 - evt. konsekvenser for tidligere vurderinger. Modtaget 04-05-2005, deadline 06-06-2005, svar 24-05-2005

    DEFF Research Database (Denmark)

    Kjellsson, Gøsta

    2012-01-01

    "Vedr. oplysningerne om iblanding af Bt-10 majsen i Bt-11 viser det tilsendte materiale, at Syngenta har undersøgt og fået bekræftet at undersøgelserne til grundlag for risikovurderingen blev foretaget på Bt-11 majs. DMU ser derfor ingen grund til at ændre konklusionerne i den tidligere risikovur...

  14. ADVERSE SELECTION, MORAL HAZARD, AND GROWER COMPLIANCE WITH BT CORN REFUGE

    OpenAIRE

    Mitchell, Paul D.; Zhu, En (John); Terrance M. Hurley

    2004-01-01

    This paper develops a principal-agent model of farmer compliance with Bt corn refuge requirements intended to manage the evolution of resistance to the Bt toxin by insect pests. The model endogenizes the price of the technology, the audit rate, and the fine imposed on non-complying farmers when farmer willingness to pay for Bt corn and compliance effort is private information.

  15. Influences of elevated CO2 and pest damage on the allocation of plant defense compounds in Bt-transgenic cotton and enzymatic activity of cotton aphid

    Institute of Scientific and Technical Information of China (English)

    Gang Wu; Fa-Jun Chen; Neng-Wen Xiao; Feng Ge

    2011-01-01

    Plant allocation to defensive compounds by elevated CO2-grown nontransgenic and transgenic Bt cotton in response to infestation by cotton aphid,Aphis gossypii (Glover) in open-top chambers under elevated CO2 were studied.The results showed that significantly lower foliar nitrogen concentration and Bt toxin protein occurred in transgenic Bt cotton with and without cotton aphid infestation under elevated CO2.However,significantly higher carbon/nitrogen ratio,condensed tannin and gossypol were observed in transgenic Bt cotton "GK-12" and non-transgenic Bt cotton ‘Simian-3' under elevated CO2.The CO2 level and cotton variety significantly influenced the foliar nitrogen,condensed tannin and gossypol concentrations in the plant leaves after feeding by A.gossypii.The interaction between CO2 level × infestation time (24 h,48 h and 72 h)showed a significant increase in cotton condensed tannin concentrations,while the interaction between CO2 level × cotton variety significantly decreased the true choline esterase (TChE) concentration in the body ofA.gossypi.This study exemplified the complexities of predicting how transgenic and non-transgenic plants will allocate defensive compounds in response to herbivorous insects under differing climatic conditions.Plant defensive compound allocation patterns and aphid enzyme changes observed in this study appear to be broadly applicable across a range of plant and herbivorous insect interactions as CO2 atmosphere rises.

  16. Genetic markers for western corn rootworm resistance to Bt toxin.

    Science.gov (United States)

    Flagel, Lex E; Swarup, Shilpa; Chen, Mao; Bauer, Christopher; Wanjugi, Humphrey; Carroll, Matthew; Hill, Patrick; Tuscan, Meghan; Bansal, Raman; Flannagan, Ronald; Clark, Thomas L; Michel, Andrew P; Head, Graham P; Goldman, Barry S

    2015-03-01

    Western corn rootworm (WCR) is a major maize (Zea mays L.) pest leading to annual economic losses of more than 1 billion dollars in the United States. Transgenic maize expressing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely used for the management of WCR. However, cultivation of Bt-expressing maize places intense selection pressure on pest populations to evolve resistance. Instances of resistance to Bt toxins have been reported in WCR. Developing genetic markers for resistance will help in characterizing the extent of existing issues, predicting where future field failures may occur, improving insect resistance management strategies, and in designing and sustainably implementing forthcoming WCR control products. Here, we discover and validate genetic markers in WCR that are associated with resistance to the Cry3Bb1 Bt toxin. A field-derived WCR population known to be resistant to the Cry3Bb1 Bt toxin was used to generate a genetic map and to identify a genomic region associated with Cry3Bb1 resistance. Our results indicate that resistance is inherited in a nearly recessive manner and associated with a single autosomal linkage group. Markers tightly linked with resistance were validated using WCR populations collected from Cry3Bb1 maize fields showing significant WCR damage from across the US Corn Belt. Two markers were found to be correlated with both diet (R2 = 0.14) and plant (R2 = 0.23) bioassays for resistance. These results will assist in assessing resistance risk for different WCR populations, and can be used to improve insect resistance management strategies. PMID:25566794

  17. Agrobacterium-meditated Genetic Transformation of an Upland Cotton (Gossypium hirsutum cv Coker 310) Using a Novel Bt Gene Cry 2Ac

    Institute of Scientific and Technical Information of China (English)

    THIRUVENGADAM V; RASHMI J A; UDYASURIAN V; BALASUBRAMANIAN P; RAVEENDRAN T S

    2008-01-01

    @@ The development of transgenic cotton varieties resistant to bollworms has been a major success of applying plant genetic engineering technology to agriculture,evidenced by phenomenal increase in the cultivable area under (B.thuringiensis) Bt cotton in recent years worldwide.Of late,there are reports of insects developing resistance against the most commonly used Bt toxin CrylAc.Hence,there is an urgent need to broaden the source of resistance by employing new genes in order to reduce the chances of insects developing Bt resistance.Keeping this objective in view,cotton (Gossypium hirsuturn cv Coker 310) plants expressing a novel insecticidal crystal protein Cry2Ac were developed in the present study.

  18. Test Takers' Attitudes about the TOEFL iBT[TM]. TOEFL iBT Research Report. RR-10-2

    Science.gov (United States)

    Stricker, Lawrence J.; Attali, Yigal

    2010-01-01

    The principal aims of this study, a conceptual replication of an earlier investigation of the TOEFL[R] computer-based test, or TOEFL CBT, in Buenos Aires, Cairo, and Frankfurt, were to assess test takers' reported acceptance of the TOEFL Internet-based test, or TOEFL iBT[TM], and its associations with possible determinants of this acceptance and…

  19. Calculation and Analysis of B/T (Burning and/or Transmutation Rate of Minor Actinides and Plutonium Performed by Fast B/T Reactor

    Directory of Open Access Journals (Sweden)

    Marsodi

    2006-01-01

    Full Text Available Calculation and analysis of B/T (Burning and/or Transmutation rate of MA (minor actinides and Pu (Plutonium has been performed in fast B/T reactor. The study was based on the assumption that the spectrum shift of neutron flux to higher side of neutron energy had a potential significance for designing the fast B/T reactor and a remarkable effect for increasing the B/T rate of MA and/or Pu. The spectrum shifts of neutron have been performed by change MOX to metallic fuel. Blending fraction of MA and or Pu in B/T fuel and the volume ratio of fuel to coolant in the reactor core were also considered. Here, the performance of fast B/T reactor was evaluated theoretically based on the calculation results of the neutronics and burn-up analysis. In this study, the B/T rate of MA and/or Pu increased by increasing the blending fraction of MA and or Pu and by changing the F/C ratio. According to the results, the total B/T rate, i.e. [B/T rate]MA + [B/T rate]Pu, could be kept nearly constant under the critical condition, if the sum of the MA and Pu inventory in the core is nearly constant. The effect of loading structure was examined for inner or outer loading of concentric geometry and for homogeneous loading. Homogeneous loading of B/T fuel was the good structure for obtaining the higher B/T rate, rather than inner or outer loading

  20. [Exposure degree of important non-target arthropods to Cry2Aa in Bt rice fields].

    Science.gov (United States)

    Zhang, Qing-Ling; Li, Yun-He; Hua, Hong-Xia; Yang, Chang-Ju; Wu, Hong-Jin; Peng, Yu-Fa

    2013-06-01

    Based on the principle of "risk = hazard x exposure", the selected representative nontarget organisms in the assessment of the potential effects of insect-resistant genetically modified (GM) crops on non-target arthropods in laboratory are generally the arthropod species highly exposed to the insecticidal proteins expressed by the GM crops in farmland ecosystem. In order to understand the exposure degree of the important arthropod species to Cry proteins in Bt rice fields, and to select the appropriate non-target arthropods in the risk assessment of insect-resistant GM crops, the enzyme-linked immunosorbent assay (ELISA) was conducted to measure the Cry2Aa protein concentration in the arthropods collected from the cry2Aa rice fields at different rice growth stages. The results showed that there was a significant difference in the Cry2Aa content protein concentration in different arthropod species. Some species did not contain Cry2Aa protein, while some species contained larger amounts of Cry2Aa protein. Relative to the arthropods colleted after rice anthesis, the arthropods colleted in rice anthesis contained relative higher concentrations of Cry2Aa protein, especially for the predacious arthropods. No Cry proteins were detected in parasitic arthropods. This study provided references for the laboratory assessment of the effects of GM rice on nontarget arthropods.

  1. FUM gene expression profile and fumonisin production by Fusarium verticillioides inoculated in Bt and non-Bt maize

    Directory of Open Access Journals (Sweden)

    Liliana Oliveira Rocha

    2016-01-01

    Full Text Available This study aimed to determine the levels of fumonisins produced by F. verticillioides and FUM gene expression on Bt (Bacillus thuringiensis and non-Bt maize, post harvest, during different periods of incubation. Transgenic hybrids 30F35 YG, 2B710 Hx and their isogenic (30F35 and 2B710 were collected from the field and a subset of 30 samples selected for the experiments. Maize samples were sterilized by gamma radiation at a dose of 20 kGy. Samples were then inoculated with Fusarium verticillioides and analysed under controlled conditions of temperature and relative humidity for fumonisin B1 and B2 (FB¬1 and FB2 production and FUM1, FUM3, FUM6, FUM7, FUM8, FUM13, FUM14, FUM15 and FUM19 expression. 2B710 Hx and 30F35 YG kernel samples were virtually intact when compared to the non-Bt hybrids that came from the field. Statistical analysis showed that FB¬1 production was significantly lower in 30F35 YG and 2B710 Hx than in the 30F35 and 2B710 hybrids (P 0.05. The kernel injuries observed in the non-Bt samples have possibly facilitated F. verticillioides penetration and promoted FB1 production under controlled conditions. FUM genes were expressed by F. verticillioides in all of the samples. However, there was indication of lower expression of a few FUM genes in the Bt hybrids; and a weak association between FB1 production and the relative expression of some of the FUM genes were observed in the 30F35 YG hybrid.

  2. FUM Gene Expression Profile and Fumonisin Production by Fusarium verticillioides Inoculated in Bt and Non-Bt Maize

    Science.gov (United States)

    Rocha, Liliana O.; Barroso, Vinícius M.; Andrade, Ludmila J.; Pereira, Gustavo H. A.; Ferreira-Castro, Fabiane L.; Duarte, Aildson P.; Michelotto, Marcos D.; Correa, Benedito

    2016-01-01

    This study aimed to determine the levels of fumonisins produced by Fusarium verticillioides and FUM gene expression on Bt (Bacillus thuringiensis) and non-Bt maize, post harvest, during different periods of incubation. Transgenic hybrids 30F35 YG, 2B710 Hx and their isogenic (30F35 and 2B710) were collected from the field and a subset of 30 samples selected for the experiments. Maize samples were sterilized by gamma radiation at a dose of 20 kGy. Samples were then inoculated with F. verticillioides and analyzed under controlled conditions of temperature and relative humidity for fumonisin B1 and B2 (FB1 and FB2) production and FUM1, FUM3, FUM6, FUM7, FUM8, FUM13, FUM14, FUM15, and FUM19 expression. 2B710 Hx and 30F35 YG kernel samples were virtually intact when compared to the non-Bt hybrids that came from the field. Statistical analysis showed that FB1 production was significantly lower in 30F35 YG and 2B710 Hx than in the 30F35 and 2B710 hybrids (P 0.05). The kernel injuries observed in the non-Bt samples have possibly facilitated F. verticillioides penetration and promoted FB1 production under controlled conditions. FUM genes were expressed by F. verticillioides in all of the samples. However, there was indication of lower expression of a few FUM genes in the Bt hybrids; and a weak association between FB1 production and the relative expression of some of the FUM genes were observed in the 30F35 YG hybrid. PMID:26779158

  3. Changes in bacillus thuringiensis tolerance levels due to hybridization of Bt-tolerant and susceptible silkworm populations

    International Nuclear Information System (INIS)

    Males and females of a Bt-tolerant mulberry silkworm (Bombyx mori L.) population were crossed with females and males of a Bt-susceptible population, to produce Bt-tolerant silkworm hybrids, and to determine the expression of the Bt-tolerance pattern in the F 1 hybrids. It was observed that when a Bt-tolerant (42% larval mortality) female (BtT ) silkworm was crossed with a Bt-susceptible (85% larval mortality) male (BtS ), the resultant F 1 offspring showed lower levels of Bt-tolerance (87% larval mortality). On the other hand, when a Bt-tolerant male (BtT ) was crossed with a Bt-susceptible female (BtS ), the F 1 hybrid showed higher levels of Bt-tolerance (35% larval mortality) characteristic. The probit statistics showed that both hybrids expressed Bt-tolerance or susceptible levels similar to their male parents. These different patterns of Bt-tolerance in F 1 hybrids might be due to the transferring of a Bt-tolerant gene, from the parents to offspring, through the homozygotic male (ZZ) silkworm. (author)

  4. Mega-nano detection of foodborne pathogens and transgenes using molecular beacon and semiconductor quantum dot technologies.

    Science.gov (United States)

    Burris, Kellie P; Wu, Tsai-Chin; Vasudev, Milana; Stroscio, Michael A; Millwood, Reginald J; Stewart, C Neal

    2013-09-01

    Signature molecules derived from Listeria monocytogenes, Bacillus thuringiensis, and Salmonella Typhimurium were detected directly on food substrates (mega) by coupling molecular beacon technology utilizing fluorescent resonance energy transfer (FRET), luminescent nanoscale semiconductor quantum dots, and nanoscale quenchers. We designed target DNA sequences for detecting hlyA, Bt cry1Ac, and invA genes from L. monocytogenes, B. thuringiensis and Salmonella Typhimurium, respectively, and prepared molecular beacons for specific targets for use in real-time monitoring. We successfully detected increased fluorescence in the presence of signature molecules at molecular beacon (MB) concentrations from 1.17 nM to 40 nM, depending upon system tested in (water, milk or plant leaves), respective target (hlyA, Bt cry1Ac, or invA) and genomic DNA target concentration (50-800 ng). We were able to detect bacterial genomic DNA derived from L. monocytogenes and Salmonella sp. in a food system, 2% milk ( > 20% of total volume). Furthermore, we infiltrated the Bt cry1Ac beacon in the presence of genomic DNA extracted from B. thuringiensis into Arabidopsis thaliana leaves and observed increased fluorescence in the presence of the target, indicating the ability to use these beacons in a plant system.

  5. Dominant inheritance of field-evolved resistance to Bt corn in Busseolafusca.

    Directory of Open Access Journals (Sweden)

    Pascal Campagne

    Full Text Available Transgenic crops expressing Bacillus thuringiensis (Bt toxins have been adopted worldwide, notably in developing countries. In spite of their success in controlling target pests while allowing a substantial reduction of insecticide use, the sustainable control of these pest populations is threatened by the evolution of resistance. The implementation of the "high dose/refuge" strategy for managing insect resistance in transgenic crops aims at delaying the evolution of resistance to Bt crops in pest populations by promoting survival of susceptible insects. However, a crucial condition for the "high dose/refuge" strategy to be efficient is that the inheritance of resistance should be functionally recessive. Busseolafusca developed high levels of resistance to the Bt toxin Cry 1Ab expressed in Bt corn in South Africa. To test whether the inheritance of B. fusca resistance to the Bt toxin could be considered recessive we performed controlled crosses with this pest and evaluated its survival on Bt and non-Bt corn. Results show that resistance of B. fusca to Bt corn is dominant, which refutes the hypothesis of recessive inheritance. Survival on Bt corn was not lower than on non-Bt corn for both resistant larvae and the F1 progeny from resistant × susceptible parents. Hence, resistance management strategies of B. fusca to Bt corn must address non-recessive resistance.

  6. Decrease in catalase activity of Folsomia candida fed a Bt rice diet

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Yiyang, E-mail: yuanyy@ioz.ac.cn [State Key Laboratory of Integrated Management of Pest and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Ke Xin, E-mail: xinke@sibs.ac.cn [Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032 (China); Chen Fajun, E-mail: fajunchen@njau.edu.cn [College of Plant Protection, Department of Entomology, Nanjing Agricultural University, Nanjing 210095 (China); Krogh, Paul Henning, E-mail: phk@dmu.dk [Department of Bioscience, University of Aarhus, P.O. Box 314, Vejlsoevej 25, DK-8600 Silkeborg (Denmark); Ge Feng, E-mail: gef@ioz.ac.cn [State Key Laboratory of Integrated Management of Pest and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101 (China)

    2011-12-15

    Here we report the effects of three Bt-rice varieties and their non-Bt conventional isolines on biological traits including survival, reproduction, and the activities of three antioxidant enzymes superoxide dismutase, catalase and peroxidase, in the Collembolan, Folsomia candida. The reproduction was significantly lower when fed Kemingdao and Huahui1 than those feeding on their non-GM near-isogenic varieties Xiushui and Minghui63 respectively, this can be explained by the differences of plant compositions depended on variety of rice. The catalase activity of F. candida was significantly lower when fed the Bt-rice variety Kemingdao compared to the near-isogenic non-Bt-rice variety Xiushui. This suggests that some Bt-rice varieties may impose environmental stress to collembolans. We emphasize that changes in activity of antioxidant enzymes of non-target organisms are important in understanding the ecological consequences for organisms inhabiting transgenic Bt-rice plantations. - Highlights: > We examine the effects of Bt-rice on Folsomia candida with laboratory test. > The reproduction of F. candida was decreased by two Bt-rice varieties. > Decreased reproduction caused by the differences of varieties or C/N ratio of rice. > The catalase activity was decreased by Bt-rice Kemingdao. > Some Bt-rice may impose environmental stress on NTOs. - The catalase of the collembolan (Folsomia candida) was decreased when fed Bt-rice, Kemingdao.

  7. The effect of Bt-transgene introgression on plant growth and reproduction in wild Brassica juncea.

    Science.gov (United States)

    Liu, Yong-Bo; Darmency, Henry; Stewart, C Neal; Wei, Wei; Tang, Zhi-Xi; Ma, Ke-Ping

    2015-06-01

    This study aims to investigate the relative plant growth and reproduction of insect-resistant and susceptible plants following the introgression of an insect-resistance Bt-transgene from Brassica napus, oilseed rape, to wild Brassica juncea. The second backcrossed generation (BC2) from a single backcross family was grown in pure and mixed stands of Bt-transgenic and non-transgenic siblings under two insect treatments. Various proportions of Bt-transgenic plants were employed in mixed stands to study the interaction between resistant and susceptible plants. In the pure stands, Bt-transgenic BC2 plants performed better than non-transgenic plants with or without insect treatments. In mixed stands, Bt-transgenic BC2 plants produced fewer seeds than their non-Bt counterparts at low proportions of Bt-transgenic BC2 plants in the absence of insects. Reproductive allocation of non-transgenic plants marginally increased with increasing proportions of Bt-transgenic plants under herbivore pressure, which resulted in increased total biomass and seed production per stand. The results showed that the growth of non-transgenic plants was protected by Bt-transgenic plants under herbivore pressure. The Bt-transgene might not be advantageous in mixed stands of backcrossed hybrids; thus transgene introgression would not be facilitated when herbivorous insects are not present. However, a relatively large initial population of Bt-transgenic plants might result in transgene persistence when target herbivores are present.

  8. Evaluation of Broiler Performance when fed insect-protected, control, or commercial varieties of dehulled Soybean Meal1.

    NARCIS (Netherlands)

    Kan, C.A.; Hartnell, G.F.

    2004-01-01

    We evaluated the nutritional value of broiler diets containing approximately 35% soybean meal from insect-protected soybean containing Cry1Ac protein, or from a similar nontransgenic control, or from 7 reference commercial soybean varieties. The feeding trial lasted 41 d, and each treatment consiste

  9. Genetic Basis of Cry1F-Resistance in a Laboratory Selected Asian Corn Borer Strain and Its Cross-Resistance to Other Bacillus thuringiensis Toxins

    Science.gov (United States)

    Wang, Yueqin; Wang, Yidong; Wang, Zhenying; Bravo, Alejandra; Soberón, Mario; He, Kanglai

    2016-01-01

    The Asian corn borer (ACB), Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae), is the most destructive insect pest of corn in China. Susceptibility to the Cry1F toxin derived from Bacillus thuringiensis has been demonstrated for ACB, suggesting the potential for Cry1F inclusion as part of an insect pest management program. Insects can develop resistance to Cry toxins, which threatens the development and use of Bt formulations and Bt crops in the field. To determine possible resistance mechanisms to Cry1F, a Cry1F-resistant colony of ACB (ACB-FR) that exhibited more than 1700-fold resistance was established through selection experiments after 49 generations of selection under laboratory conditions. The ACB-FR strain showed moderate cross-resistance to Cry1Ab and Cry1Ac of 22.8- and 26.9-fold, respectively, marginally cross-resistance to Cry1Ah (3.7-fold), and no cross-resistance to Cry1Ie (0.6-fold). The bioassay responses of progeny from reciprocal F1 crosses to different Cry1 toxin concentrations indicated that the resistance trait to Cry1Ab, Cry1Ac and Cry1F has autosomal inheritance with no maternal effect or sex linked. The effective dominance (h) of F1 offspring was calculated at different concentrations of Cry1F, showing that h decreased as concentration of Cry1F increased. Finally, the analysis of actual and expected mortality of the progeny from a backcross (F1 × resistant strain) indicated that the inheritance of the resistance to Cry1F in ACB-FR was due to more than one locus. The present study provides an understanding of the genetic basis of Cry1F resistance in ACB-FR and also shows that pyramiding Cry1F with Cry1Ah or Cry1Ie could be used as a strategy to delay the development of ACB resistance to Bt proteins. PMID:27518813

  10. Genetic Basis of Cry1F-Resistance in a Laboratory Selected Asian Corn Borer Strain and Its Cross-Resistance to Other Bacillus thuringiensis Toxins.

    Science.gov (United States)

    Wang, Yueqin; Wang, Yidong; Wang, Zhenying; Bravo, Alejandra; Soberón, Mario; He, Kanglai

    2016-01-01

    The Asian corn borer (ACB), Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae), is the most destructive insect pest of corn in China. Susceptibility to the Cry1F toxin derived from Bacillus thuringiensis has been demonstrated for ACB, suggesting the potential for Cry1F inclusion as part of an insect pest management program. Insects can develop resistance to Cry toxins, which threatens the development and use of Bt formulations and Bt crops in the field. To determine possible resistance mechanisms to Cry1F, a Cry1F-resistant colony of ACB (ACB-FR) that exhibited more than 1700-fold resistance was established through selection experiments after 49 generations of selection under laboratory conditions. The ACB-FR strain showed moderate cross-resistance to Cry1Ab and Cry1Ac of 22.8- and 26.9-fold, respectively, marginally cross-resistance to Cry1Ah (3.7-fold), and no cross-resistance to Cry1Ie (0.6-fold). The bioassay responses of progeny from reciprocal F1 crosses to different Cry1 toxin concentrations indicated that the resistance trait to Cry1Ab, Cry1Ac and Cry1F has autosomal inheritance with no maternal effect or sex linked. The effective dominance (h) of F1 offspring was calculated at different concentrations of Cry1F, showing that h decreased as concentration of Cry1F increased. Finally, the analysis of actual and expected mortality of the progeny from a backcross (F1 × resistant strain) indicated that the inheritance of the resistance to Cry1F in ACB-FR was due to more than one locus. The present study provides an understanding of the genetic basis of Cry1F resistance in ACB-FR and also shows that pyramiding Cry1F with Cry1Ah or Cry1Ie could be used as a strategy to delay the development of ACB resistance to Bt proteins. PMID:27518813

  11. Aryl Hydrocarbon Receptor (AHR)-Active Pharmaceuticals Are Selective AHR Modulators in MDA-MB-468 and BT474 Breast Cancer Cells

    OpenAIRE

    Jin, Un-Ho; Lee, Syng-Ook; Safe, Stephen

    2012-01-01

    Leflunomide, flutamide, nimodipine, mexiletine, sulindac, tranilast, 4-hydroxytamoxifen, and omeprazole are pharmaceuticals previously characterized as aryl hydrocarbon receptor (AHR) agonists in various cell lines and animal models. In this study, the eight AHR-active pharmaceuticals were investigated in highly aggressive aryl hydrocarbon (Ah)-responsive BT474 and MDA-MB-468 breast cancer cell lines, and their effects on AHR protein, CYP1A1 (protein and mRNA), CYP1B1 (mRNA), and cell migrati...

  12. Sequence variation and differential splicing of the midgut cadherin gene in Trichoplusia ni.

    Science.gov (United States)

    Zhang, Xin; Kain, Wendy; Wang, Ping

    2013-08-01

    The insect midgut cadherin serves as an important receptor for the Cry toxins from Bacillus thuringiensis (Bt). Variation of the cadherin in insect populations provides a genetic potential for development of cadherin-based Bt resistance in insect populations. Sequence analysis of the cadherin from the cabbage looper, Trichoplusia ni, together with cadherins from 18 other lepidopterans showed a similar phylogenetic relationship of the cadherins to the phylogeny of Lepidoptera. The midgut cadherin in three laboratory populations of T. ni exhibited high variability, although the resistance to Bt toxin Cry1Ac in the T. ni strain is not genetically associated with cadherin gene mutations. A total of 142 single nucleotide polymorphisms (SNPs) were identified in the cadherin cDNAs from the T. ni strains, including 20 missense mutations. In addition, insertion and deletion polymorphisms (indels) were also identified in the cadherin alleles in T. ni. More interestingly, the results from this study reveal that differential splicing of mRNA also occurs in the cadherin gene expression. Therefore, variation of the midgut cadherin in insects may not only be caused by cadherin gene mutations, but could also result from alternative splicing of its mRNA regulated by factors acting in trans. Analysis of cadherin gene alleles in F2, F3 and F4 progenies from the cross between the Cry1Ac resistant and the susceptible strain after consecutive selections with Cry1Ac for three generations showed that selection with Cry1Ac did not result in an increase of frequencies of the cadherin alleles originated from the resistant strain. PMID:23743444

  13. Expresión de la proteína Cry1Ac en tejidos de líneas transgénicas de papa (Solanum tuberosum spp. Andígena) Var. Diacol capiro.

    OpenAIRE

    Blanco Martinez Jennifer Teresa; Vanegas Araujo Pablo Andres; Chaparro Giraldo Alejandro

    2010-01-01

    RESUMEN

  14. Assessing Fungal Population in Soil Planted with Cry1Ac and CPTI Transgenic Cotton and Its Conventional Parental Line Using 18S and ITS rDNA Sequences over Four Seasons.

    Science.gov (United States)

    Qi, Xiemin; Liu, Biao; Song, Qinxin; Zou, Bingjie; Bu, Ying; Wu, Haiping; Ding, Li; Zhou, Guohua

    2016-01-01

    Long-term growth of genetically modified plants (GMPs) has raised concerns regarding their ecological effects. Here, FLX-pyrosequencing of region I (18S) and region II (ITS1, 5.8S, and ITS2) rDNA was used to characterize fungal communities in soil samples after 10-year monoculture of one representative transgenic cotton line (TC-10) and 15-year plantation of various transgenic cotton cultivars (TC-15mix) over four seasons. Soil fungal communities in the rhizosphere of non-transgenic control (CC) were also compared. No notable differences were observed in soil fertility variables among CC, TC-10, and TC-15mix. Within seasons, the different estimations were statistically indistinguishable. There were 411 and 2 067 fungal operational taxonomic units in the two regions, respectively. More than 75% of fungal taxa were stable in both CC and TC except for individual taxa with significantly different abundance between TC and CC. Statistical analysis revealed no significant differences between CC and TC-10, while discrimination of separating TC-15mix from CC and TC-10 with 37.86% explained variance in PCoA and a significant difference of Shannon indexes between TC-10 and TC-15mix were observed in region II. As TC-15mix planted with a mixture of transgenic cottons (Zhongmian-29, 30, and 33B) for over 5 years, different genetic modifications may introduce variations in fungal diversity. Further clarification is necessary by detecting the fungal dynamic changes in sites planted in monoculture of various transgenic cottons. Overall, we conclude that monoculture of one representative transgenic cotton cultivar may have no effect on fungal diversity compared with conventional cotton. Furthermore, the choice of amplified region and methodology has potential to affect the outcome of the comparison between GM-crop and its parental line. PMID:27462344

  15. Assessing Fungal Population in Soil Planted with Cry1Ac and CPTI Transgenic Cotton and Its Conventional Parental Line Using 18S and ITS rDNA Sequences over Four Seasons

    Science.gov (United States)

    Qi, Xiemin; Liu, Biao; Song, Qinxin; Zou, Bingjie; Bu, Ying; Wu, Haiping; Ding, Li; Zhou, Guohua

    2016-01-01

    Long-term growth of genetically modified plants (GMPs) has raised concerns regarding their ecological effects. Here, FLX-pyrosequencing of region I (18S) and region II (ITS1, 5.8S, and ITS2) rDNA was used to characterize fungal communities in soil samples after 10-year monoculture of one representative transgenic cotton line (TC-10) and 15-year plantation of various transgenic cotton cultivars (TC-15mix) over four seasons. Soil fungal communities in the rhizosphere of non-transgenic control (CC) were also compared. No notable differences were observed in soil fertility variables among CC, TC-10, and TC-15mix. Within seasons, the different estimations were statistically indistinguishable. There were 411 and 2 067 fungal operational taxonomic units in the two regions, respectively. More than 75% of fungal taxa were stable in both CC and TC except for individual taxa with significantly different abundance between TC and CC. Statistical analysis revealed no significant differences between CC and TC-10, while discrimination of separating TC-15mix from CC and TC-10 with 37.86% explained variance in PCoA and a significant difference of Shannon indexes between TC-10 and TC-15mix were observed in region II. As TC-15mix planted with a mixture of transgenic cottons (Zhongmian-29, 30, and 33B) for over 5 years, different genetic modifications may introduce variations in fungal diversity. Further clarification is necessary by detecting the fungal dynamic changes in sites planted in monoculture of various transgenic cottons. Overall, we conclude that monoculture of one representative transgenic cotton cultivar may have no effect on fungal diversity compared with conventional cotton. Furthermore, the choice of amplified region and methodology has potential to affect the outcome of the comparison between GM-crop and its parental line. PMID:27462344

  16. The impact of common smut(Ustilago maydis) on aflatoxin and fumonisin in transgenic Bt and non-Bt maize (Zea mays)

    Science.gov (United States)

    Corn infected with Ustilago maydis (common smut), produces galls that are valued food in certain cultures, but may be contaminated with mycotoxins. Field studies conducted in Elizabeth, Mississippi used near-isogenic Bt and non-Bt corn hybrids. The levels of aflatoxin and fumonisin were determined ...

  17. Survival of Corn Earworm (Lepidoptera: Noctuidae) on Bt Maize and Cross-Pollinated Refuge Ears From Seed Blends.

    Science.gov (United States)

    Crespo, André Luiz Barreto; Alves, Analiza Piovesan; Wang, Yiwei; Hong, Bonnie; Flexner, John Lindsey; Catchot, Angus; Buntin, David; Cook, Donald

    2016-02-01

    Refuge is mandated in the United States where genetically modified maize (Zea mays L.) expressing insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) are cultivated. Currently, refuge is deployed in different ways including blocks, field strips, or seed blends containing Bt and non-Bt maize. Seed blends provide practical advantages for refuge implementation. However, concerns related to the movement of insect larvae, potential differential survival of heterozygous resistant larvae, reduction in insect production, and cross-pollination of ears resulting in sublethal selection, have delayed seed blend use for Lepidoptera in the southern United States, where maize plantings are used as refuge for Helicoverpa zea (Boddie). In this study, we evaluated the relative survival of H. zea in Bt events and in seed blends compared with pure stand refuge and the relative survival of H. zea on the individual components of the pyramid 1507xMON810xMIR162. The results showed variation on the production of H. zea in refuge plants from seed blends compared with pure stand refuge plants. The relative survival of H. zea on the events 1507, MON810, MIR162, and 1507xMON810xMIR162 ranked similarly across the three locations tested. These results can be used in computer simulation modeling efforts to evaluate the feasibility of seed blends as a refuge deployment strategy with the pyramid 1507xMON810xMIR162. Because the reduction on survival of H. zea due to blending was variable, a sensitivity analysis that includes all possible scenarios of reduction in survival should be considered. PMID:26357846

  18. Vip3A resistance alleles exist at high levels in Australian targets before release of cotton expressing this toxin.

    Directory of Open Access Journals (Sweden)

    Rod J Mahon

    Full Text Available Crops engineered to produce insecticidal crystal (Cry proteins from the soil bacterium Bacillus thuringiensis (Bt have revolutionised pest control in agriculture. However field-level resistance to Bt has developed in some targets. Utilising novel vegetative insecticidal proteins (Vips, also derived from Bt but genetically distinct from Cry toxins, is a possible solution that biotechnical companies intend to employ. Using data collected over two seasons we determined that, before deployment of Vip-expressing plants in Australia, resistance alleles exist in key targets as polymorphisms at frequencies of 0.027 (n = 273 lines, 95% CI = 0.019-0.038 in H. armigera and 0.008 (n = 248 lines, 0.004-0.015 in H. punctigera. These frequencies are above mutation rates normally encountered. Homozygous resistant neonates survived doses of Vip3A higher than those estimated in field-grown plants. Fortunately the resistance is largely, if not completely, recessive and does not confer resistance to the Bt toxins Cry1Ac or Cry2Ab already deployed in cotton crops. These later characteristics are favourable for resistance management; however the robustness of Vip3A inclusive varieties will depend on resistance frequencies to the Cry toxins when it is released (anticipated 2016 and the efficacy of Vip3A throughout the season. It is appropriate to pre-emptively screen key targets of Bt crops elsewhere, especially those such as H. zea in the USA, which is not only closely related to H. armigera but also will be exposed to Vip in several varieties of cotton and corn.

  19. Structure of a SusD Homologue, BT1043, Involved in Mucin O-Glycan Utilization in a Prominent Human Gut Symbiont

    Energy Technology Data Exchange (ETDEWEB)

    Koropatkin, Nicole; Martens, Eric C.; Gordon, Jeffrey I.; Smith, Thomas J.; (Danforth); (WU-MED)

    2009-05-21

    Mammalian distal gut bacteria have an expanded capacity to utilize glycans. In the absence of dietary sources, some species rely on host-derived mucosal glycans. The ability of Bacteroides thetaiotaomicron, a prominent human gut symbiont, to forage host glycans contributes to both its ability to persist within an individual host and its ability to be transmitted naturally to new hosts at birth. The molecular basis of host glycan recognition by this species is still unknown but likely occurs through an expanded suite of outermembrane glycan-binding proteins that are the primary interface between B. thetaiotaomicron and its environment. Presented here is the atomic structure of the B. thetaiotaomicron protein BT1043, an outer membrane lipoprotein involved in host glycan metabolism. Despite a lack of detectable amino acid sequence similarity, BT1043 is a structural homologue of the B. thetaiotaomicron starch-binding protein SusD. Both structures are dominated by tetratrico peptide repeats that may facilitate association with outer membrane {beta}-barrel transporters required for glycan uptake. The structure of BT1043 complexed with N-acetyllactosamine reveals that recognition is mediated via hydrogen bonding interactions with the reducing end of {beta}-N-acetylglucosamine, suggesting a role in binding glycans liberated from the mucin polypeptide. This is in contrast to CBM 32 family members that target the terminal nonreducing galactose residue of mucin glycans. The highly articulated glycan-binding pocket of BT1043 suggests that binding of ligands to BT1043 relies more upon interactions with the composite sugar residues than upon overall ligand conformation as previously observed for SusD. The diversity in amino acid sequence level likely reflects early divergence from a common ancestor, while the unique and conserved {alpha}-helical fold the SusD family suggests a similar function in glycan uptake.

  20. Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding.

    Science.gov (United States)

    Chakroun, Maissa; Banyuls, Núria; Walsh, Tom; Downes, Sharon; James, Bill; Ferré, Juan

    2016-01-01

    Crops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past four seasons until 2014/15. Three new isofemale lines were determined to be allelic with previously isolated lines, suggesting that they belong to one common gene and this mechanism is relatively frequent. Vip3Aa-resistance does not confer cross-resistance to Cry1Ac or Cry2Ab. Vip3Aa was labeled with (125)I and used to show specific binding to H. armigera brush-border membrane vesicles (BBMV). Binding was of high affinity (Kd = 25 and 19 nM for susceptible and resistant insects, respectively) and the concentration of binding sites was high (Rt = 140 pmol/mg for both). Despite the narrow-spectrum resistance, binding of (125)I-labeled Vip3Aa to BBMV of resistant and susceptible insects was not significantly different. Proteolytic conversion of Vip3Aa protoxin into the activated toxin rendered the same products, though it was significantly slower in resistant insects. PMID:27095284

  1. Photothermal effects of multi-walled carbon nanotubes on the viability of BT-474 cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Hung-Tao [Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Sec. 2 Kuang-Fu Rd., Hsin-chu 30013, Taiwan (China); Wang, Tsung-Pao [Department of Medical Science, National Tsing Hua University, No. 101, Sec. 2 Kuang-Fu Rd., Hsin-chu 30013, Taiwan (China); Lee, Chi-Young [Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Sec. 2 Kuang-Fu Rd., Hsin-chu 30013, Taiwan (China); Tai, Nyan-Hwa, E-mail: nhtai@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Sec. 2 Kuang-Fu Rd., Hsin-chu 30013, Taiwan (China); Chang, Hwan-You, E-mail: hychang@mx.nthu.edu.tw [Department of Medical Science, National Tsing Hua University, No. 101, Sec. 2 Kuang-Fu Rd., Hsin-chu 30013, Taiwan (China)

    2013-03-01

    Functionalized multi-walled carbon nanotubes (f-MWCNTs) were conjugated to an antibody of BT-474 cancer cells (f-MWCNTs-ab), and the photothermal effect of the f-MWCNTs-ab for BT-474 cancer cell destruction was demonstrated. After near-infrared irradiation, the f-MWCNTs-ab were more capable of killing cancer cells and possessed higher cell specificity than f-MWCNTs. Quantitative results showed that the viability of the cancer cells was affected by the concentration of the f-MWCNTs-ab solution, irradiation time, and settling time after irradiation. The membrane impermeable fluorescence dye ethidium bromide was used to detect cell viability after near-infrared irradiation, and the results agreed with those obtained from the Alamar Blue cell viability assay. The EtBr fluorescence results suggest that the cell membrane, attached to f-MWCNTs-ab, was damaged after irradiation, which led to cell death and necrosis. Using confocal microscopy, a few f-MWCNTs-ab were detected in the cell, indicating the endocytosis effect. The results not only explain the improved efficiency of thermotherapy but also indicate that necrosis may result from protein denaturation attributing to the heated f-MWCNTs-ab in the cell. Highlights: Black-Right-Pointing-Pointer f-MWCNTs conjugated with anti-HER2 antibody by chemical method. Black-Right-Pointing-Pointer Kill breast cancer cells by using low dose f-MWCNTs-ab due to photothermal effect. Black-Right-Pointing-Pointer Use EtBr fluorescent to prove that the cell membrane was broken by heated f-MWCNTs. Black-Right-Pointing-Pointer Few f-MWCNTs-ab were detected in the cell indicating the endocytosis effect. Black-Right-Pointing-Pointer Necrosis may result from protein denaturation due to contact with the heated CNTs.

  2. Improved Agrobacterium-mediated transformation of cowpea via sonication and vacuum infiltration.

    Science.gov (United States)

    Bakshi, Souvika; Sadhukhan, Ayan; Mishra, Sagarika; Sahoo, Lingaraj

    2011-12-01

    An improved method of Agrobacterium-mediated transformation of cowpea was developed employing both sonication and vacuum infiltration treatments. 4 day-old cotyledonary nodes were used as explants for co-cultivation with Agrobacterium tumefaciens strain EHA105 harbouring the binary vector pSouv-cry1Ac. Among the different injury treatments, vacuum infiltration and their combination treatments tested, sonication for 20 s followed by vacuum infiltration for 5 min with A. tumefaciens resulted in highest transient GUS expression efficiency (93% explants expressing GUS at regenerating sites). After 3 days of co-cultivation, the explants were cultured in 150 mg/l kanamycin-containing selection medium and putative transformed plants were recovered. The presence, integration and expression of nptII and cry1Ac genes in T0 transgenic plants were confirmed by polymerase chain reaction (PCR), genomic Southern and qualitative reverse transcription (RT)-PCR analysis. Western blot hybridization and enzyme-linked immunosorbent assay (ELISA) detected and demonstrated the accumulation of Cry1Ac protein in transgenic plants. The cry1Ac gene transmitted in a Mendelian fashion. The stable transformation efficiency increased by 88.4% using both sonication-assisted Agrobacterium-mediated transformation (SAAT) and vacuum infiltration than simple Agrobacterium-mediated transformation in cowpea.

  3. Estimating the Benefits of Bt Corn and Cost of Insect Resistance Management Ex Ante

    OpenAIRE

    Terrance M. Hurley; Langrock, Ines; Ostlie, Kenneth

    2006-01-01

    This paper estimates farmer benefits for corn rootworm (CRW) active Bt corn and costs of complying with Environmental Protection Agency insect resistance management requirements. The estimates are obtained from farmer survey data that were collected in Minnesota in 2002, just prior to the commercial releases of CRW Bt corn. Benefit estimates range from $14 to $33.4 million, while compliance cost estimated range from $3.5 to $8.7 million depending on whether or not CRW Bt corn also controlled ...

  4. Modified accumulation of selected heavy metals in Bt transgenic rice

    Institute of Scientific and Technical Information of China (English)

    WANG Haiyan; HUANG Jianzhong; YE Qingfu; WU Dianxing; CHEN Ziyuan

    2009-01-01

    Safety assessment of genetically modified crops generally does not take into account the potential hazard of altered patterns of heavy metal accumulation in plants.A pot experiment was conducted under greenhouse conditions to evaluate the impact of heavy metal amendments on the accumulation of Cd,Cu,Pb and Zn in a Bt transgenic rice Ke-Ming-Dao (KMD) and its wild-type Xiushui 11 (Xs11).In control soils,significant difference was only found in contents of Cu (p < 0.01) and Pb (p < 0.05) in straw between KMD and Xs11.At three levels of Cd amendments (5,10,and 20 mg/kg),the Cd contents in grain and straw of KMD were significantly higher than those of Xs11,and all grain Cd contents were significantly higher than the international criteria (0.2-0.4 mg/kg) as specified by the Codex Alimentarius Commission (CAC).These results implied that it may be unsafe for growing Bt transgenic rice in heavily Cd-polluted areas.No significant difference in Zn was found between the two varieties with the exception of roots at Zn amendment level of 600 mg/kg,while Pb contents in KMD were much higher in the straw at the lead amendment level of 1000 mg/kg and in the root at 250 mg Pb/kg.Data on the heavy metal accumulation patterns for the genetically modified rice may be used for the selection of growing areas as well as for plant residue management for Bt rice.

  5. Cross-pollination of nontransgenic corn ears with transgenic Bt corn: efficacy against lepidopteran pests and implications for resistance management.

    Science.gov (United States)

    Burkness, E C; O'Rourke, P K; Hutchison, W D

    2011-10-01

    The efficacy of nontransgenic sweet corn, Zea mays L., hybrids cross-pollinated by Bacillus thuringiensis (Bt) sweet corn hybrids expressing Cry1Ab toxin was evaluated in both field and laboratory studies in Minnesota in 2000. Non-Bt and Bt hybrids (maternal plants) were cross-pollinated with pollen from both non-Bt and Bt hybrids (paternal plants) to create four crosses. Subsequent crosses were evaluated for efficacy in the field against European corn borer, Ostrinia nubilalis (Hübner), and corn earworm, Helicoverpa zea (Boddie), and in laboratory bioassays against O. nubilalis. Field studies indicated that crosses with maternal Bt plants led to low levels of survival for both O. nubilalis and H. zea compared with the non-Bt x non-Bt cross. However, the cross between non-Bt ears and Bt pollen led to survival rates of 43 and 63% for O. nubilalis and H. zea larvae, respectively. This intermediate level of survival also was reflected in the number of kernels damaged. Laboratory bioassays for O. nubilalis, further confirmed field results with larval survival on kernels from the cross between non-Bt ears and Bt pollen reaching 60% compared with non-Bt crossed with non-Bt. These results suggest that non-Bt refuge plants, when planted in proximity to Bt plants, and cross-pollinated, can result in sublethal exposure of O. nubilalis and H. zea larvae to Bt and may undermine the high-dose/refuge resistance management strategy for corn hybrids expressing Cry1Ab.

  6. Strong oviposition preference for Bt over non-Bt maize in Spodoptera frugiperda and its implications for the evolution of resistance

    Science.gov (United States)

    2014-01-01

    Background Transgenic crops expressing Bt toxins have substantial benefits for growers in terms of reduced synthetic insecticide inputs, area-wide pest management and yield. This valuable technology depends upon delaying the evolution of resistance. The ‘high dose/refuge strategy’, in which a refuge of non-Bt plants is planted in close proximity to the Bt crop, is the foundation of most existing resistance management. Most theoretical analyses of the high dose/refuge strategy assume random oviposition across refugia and Bt crops. Results In this study we examined oviposition and survival of Spodoptera frugiperda across conventional and Bt maize and explored the impact of oviposition behavior on the evolution of resistance in simulation models. Over six growing seasons oviposition rates per plant were higher in Bt crops than in refugia. The Cry1F Bt maize variety retained largely undamaged leaves, and oviposition preference was correlated with the level of feeding damage in the refuge. In simulation models, damage-avoiding oviposition accelerated the evolution of resistance and either led to requirements for larger refugia or undermined resistance management altogether. Since larval densities affected oviposition preferences, pest population dynamics affected resistance evolution: larger refugia were weakly beneficial for resistance management if they increased pest population sizes and the concomitant degree of leaf damage. Conclusions Damaged host plants have reduced attractiveness to many insect pests, and crops expressing Bt toxins are generally less damaged than conventional counterparts. Resistance management strategies should take account of this behavior, as it has the potential to undermine the effectiveness of existing practice, especially in the tropics where many pests are polyvoltinous. Efforts to bring down total pest population sizes and/or increase the attractiveness of damaged conventional plants will have substantial benefits for slowing the

  7. Effects of feeding Bt maize to sows during gestation and lactation on maternal and offspring immunity and fate of transgenic material.

    Directory of Open Access Journals (Sweden)

    Stefan G Buzoianu

    Full Text Available BACKGROUND: We aimed to determine the effect of feeding transgenic maize to sows during gestation and lactation on maternal and offspring immunity and to assess the fate of transgenic material. METHODOLOGY/PRINCIPAL FINDINGS: On the day of insemination, sows were assigned to one of two treatments (n = 12/treatment; 1 non-Bt control maize diet or 2 Bt-MON810 maize diet, which were fed for ~143 days throughout gestation and lactation. Immune function was assessed by leukocyte phenotyping, haematology and Cry1Ab-specific antibody presence in blood on days 0, 28 and 110 of gestation and at the end of lactation. Peripheral-blood mononuclear cell cytokine production was investigated on days 28 and 110 of gestation. Haematological analysis was performed on offspring at birth (n = 12/treatment. Presence of the cry1Ab transgene was assessed in sows' blood and faeces on day 110 of gestation and in blood and tissues of offspring at birth. Cry1Ab protein presence was assessed in sows' blood during gestation and lactation and in tissues of offspring at birth. Blood monocyte count and percentage were higher (P<0.05, while granulocyte percentage was lower (P<0.05 in Bt maize-fed sows on day 110 of gestation. Leukocyte count and granulocyte count and percentage were lower (P<0.05, while lymphocyte percentage was higher (P<0.05 in offspring of Bt maize-fed sows. Bt maize-fed sows had a lower percentage of monocytes on day 28 of lactation and of CD4(+CD8(+ lymphocytes on day 110 of gestation, day 28 of lactation and overall (P<0.05. Cytokine production was similar between treatments. Transgenic material or Cry1Ab-specific antibodies were not detected in sows or offspring. CONCLUSIONS/SIGNIFICANCE: Treatment differences observed following feeding of Bt maize to sows did not indicate inflammation or allergy and are unlikely to be of major importance. These results provide additional data for Bt maize safety assessment.

  8. FARMER DEMAND FOR CORN ROOTWORM BT CORN: DO INSECT RESISTANCE MANAGEMENT GUIDELINES MATTER?

    OpenAIRE

    Langrock, Ines; Terrance M. Hurley; Ostlie, Kenneth

    2003-01-01

    Farmer adoption of Bt corn and compliance with insect resistance management (IRM) regulations will influence the success of these regulations. The purpose of this paper is to use farmer survey data to estimate the demand for new corn rootworm Bt corn and the cost of complying with proposed IRM regulations.

  9. Effects of Transgenic Bt Cotton on Insecticide Use and Predatory Insect Abundance

    Science.gov (United States)

    Considerable effort has been expended to determine if crops genetically engineered to produce Bacillus thuringiensis (Bt) toxins harm non-target arthropods. However, if Bt crops kill target pests and thereby reduce insecticide use, this could benefit some non-target arthropods. We analyzed data fr...

  10. Delta's Key to the TOEFL iBT[R]: Advanced Skill Practice. Revised Edition

    Science.gov (United States)

    Gallagher, Nancy

    2012-01-01

    Delta's Key to the TOEFL iBT: Advanced Skill Practice is a revised and updated edition of Delta's Key to the Next Generation TOEFL Test. Since the introduction of the TOEFL iBT in 2005, there have been significant changes to some of the test questions, particularly the integrated writing and integrated speaking tasks. The new 2011 edition of…

  11. Data of evolutionary structure change: 1BT8B-1UNFX [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1BT8B-1UNFX 1BT8 1UNF B X ---AVYTLPELPYDYSALEPYISGEIMELHHDKHHKAYV...EEEEEEEEEGGG EEEEEEE EEE EEE HHHH HHHHHHHHHH EEHHHHHHHHHHHHHH EVID> 1UNF X 1UNFX VN...d>2.942183017730713 5.374790191650391 ...> TRP CA 395 ASP CA 318 ASP CA 362 1UNF

  12. Resistance to Bt maize by western corn rootworm: insights from the laboratory and the field.

    Science.gov (United States)

    Gassmann, Aaron J

    2016-06-01

    Western corn rootworm is a serious pest of maize. Beginning in 2003, management of western corn rootworm included transgenic maize that produces insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). The first Bt maize hybrids produced Cry3Bb1, but additional Bt toxins have since been introduced, including eCry3.1Ab, mCry3A and Cry34/35Ab1. Laboratory selection experiments found that western corn rootworm could develop resistance to all types of Bt maize following three to seven generations of selection. By 2009 cases of field-evolved resistance to Cry3Bb1 maize had been identified, with populations also showing cross-resistance to mCry3A maize. Factors likely contributing to resistance were the lack of a high dose of Bt toxin for maize targeting rootworm and minimal fitness costs of resistance. PMID:27436740

  13. Persistence of Bt Bacillus thuringiensis Cry1Aa toxin in various soils determined by physicochemical reactions

    Science.gov (United States)

    Helassa, N.; Noinville, S.; Déjardin, P.; Janot, J. M.; Quiquampoix, H.; Staunton, S.

    2009-04-01

    Insecticidal Cry proteins from the soil bacterium, Bacillus thuringiensis (Bt) are produced by a class of genetically modified (GM) crops, and released into soils through root exudates and upon decomposition of residues. In contrast to the protoxin produced by the Bacillus, the protein produced in GM crops does not require activation in insect midguts and thereby potentially looses some of its species specificity. Although gene transfer and resistance emergence phenomena are well documented, the fate of these toxins in soil has not yet been clearly elucidated. Cry proteins, in common with other proteins, are adsorbed on soils and soil components. Adsorption on soil, and the reversibility of this adsorption is an important aspect of the environmental behaviour of these toxins. The orientation of the molecule and conformational changes on surfaces may modify the toxicity and confer some protection against microbial degradation. Adsorption will have important consequences for both the risk of exposition of non target species and the acquisition of resistance by target species. We have adopted different approaches to investigate the fate of Cry1Aa in soils and model minerals. In each series of experiments we endeavoured to maintain the protein in a monomeric form (pH above 6.5 and a high ionic strength imposed with 150 mM NaCl). The adsorption and the desorbability of the Cry1Aa Bt insecticidal protein were measured on two different homoionic clays: montmorillonite and kaolinite. Adsorption isotherms obtained followed a low affinity interaction for both clays and could be fitted using the Langmuir equation. Binding of the toxin decreased as the pH increased from 6.5 (close to the isoelectric point) to 9. Maximum adsorption was about 40 times greater on montmorillonite (1.71 g g-1) than on kaolinite (0.04 g g-1) in line with the contrasting respective specific surface areas of the minerals. Finally, some of the adsorbed toxin was desorbed by water and more, about 36

  14. Does the growing of Bt maize change populations or ecological functions of non-target animals compared to the growing of conventional non-GM maize? A systematic review protocol

    Science.gov (United States)

    Since 1996, genetically modified (GM) crops have been grown on an ever increasing area worldwide. Maize producing a Cry protein from the bacterium Bacillus thuringiensis (Bt) was among the first GM crops released for commercial production and it is the only GM crop currently cultivated in Europe. A ...

  15. Effects of Bt transgenic crops on soil ecosystems: a review of a ten-year research in China

    Institute of Scientific and Technical Information of China (English)

    Wenke LIU

    2009-01-01

    Bacillus thuringiensis (Bt) transgenic cotton is the unique Bt transgenic crop planted on a large scale in China, and its commercialized varieties and hectareage had increased rapidly in China during the past decade (1997-2006) with broad geographic distribution for the economic, environmental, and health benefits. In 2004, the planting area of Bt transgenic cotton in China ranked first worldwide with up to 370 × 106hm2. In addition, Bt transgenic rice varieties in field tests have been close to approval for commercialization. However, ecological risks, a complex issue of Bt transgenic crops on soil ecosystem is urgently faced in China due to more than 60 varieties transferred single or bivalent Bt genes grown under diverse geographic regions. Two main pathways, biomass incorporation and root exudates, are involved in the effects of Bt transgenic crops on soil ecosystems. In this paper, the research results in recent years in China involved in the effects of Bt transgenic crops (Bt transgenic cottons and rice) on soil ecosystems were summarized with special attentions paid to the release and persistence of Bt toxins, and the toxicology to microorganisms, as well as the change of soil biochemical properties in soils where Bt transgenic crops were planted or incubated with their biomass. In addition, the complexity and current research defaults of ecological risk evaluation of Bt transgenic crops in China were highlighted.

  16. Decrease in catalase activity of Folsomia candida fed a Bt rice diet

    DEFF Research Database (Denmark)

    Yuan, Yiyang; Ke, Xin; Chen, Fajun;

    2011-01-01

    the Bt-rice variety Kemingdao compared to the near-isogenic non-Bt-rice variety Xiushui. This suggests that some Bt-rice varieties may impose environmental stress to collembolans. We emphasize that changes in activity of antioxidant enzymes of non-target organisms are important in understanding...

  17. Emergence and Abundance of Western Corn Rootworm (Coleoptera: Chrysomelidae) in Bt Cornfields With Structured and Seed Blend Refuges.

    Science.gov (United States)

    Hughson, Sarah A; Spencer, Joseph L

    2015-02-01

    To slow evolution of western corn rootworm (Diabrotica virgifera virgifera LeConte) resistance to Bt (Bacillus thuringiensis Berliner) corn hybrids, non-Bt "refuges" must be planted within or adjacent to Bt cornfields, allowing susceptible insects to develop without exposure to Bt toxins. Bt-susceptible adults from refuges are expected to find and mate with resistant adults that have emerged from Bt corn, reducing the likelihood that Bt-resistant offspring are produced. The spatial and temporal distribution of adults in four refuge treatments (20, 5, and 0% structured refuges and 5% seed blend) and adjacent soybean fields was compared from 2010 to 2012. Adult emergence (adults/trap/day) from refuge corn in structured refuge treatments was greater than that from Bt corn, except during the post-pollination period of corn phenology when emergence from refuge and Bt plants was often the same. Abundance of free-moving adults was greatest in and near refuge rows in structured refuge treatments during vegetative and pollination periods. By post-pollination, adult abundance became evenly distributed. In contrast, adult abundance in 5% seed blends and 0% refuges was evenly distributed, or nearly so, across plots throughout the season. The persistent concentration of adults in refuge rows suggests that structured refuge configurations may not facilitate the expected mixing of adults from refuge and Bt corn. Seed blends produce uniform distributions of adults across the field that may facilitate mating between Bt and refuge adults and ultimately delay the evolution of Bt resistance. PMID:26470111

  18. Effects of Transgenic Bt Maize on Soil Nutrient Content%转 Bt 基因玉米对土壤养分含量的影响

    Institute of Scientific and Technical Information of China (English)

    景小鹏; 李建东; 周旭梅; 景希强

    2015-01-01

    The transgenic Bt maize Dan BT01 was used as the subjects to study on the effects of transgenic Bt maize on farmland nutrition in different growth periods of seedling stage,jointing stage,huge bellbottom stage, tasseling stage,silking stage and mature stage under field condition.The results showed that oil organic matter content at the tasseling stage and mature stage,total phosphorus content at the silking stage,slowly available potassium concentrations at the huge bellbottom stage and mature stage of transgenic Bt maize were significant-ly higher than the non-transgenic maize,and there was no significant difference of the oil organic matter con-tent,total nitrogen,total phosphorus content and slowly available potassium concentrations at the other growth stages.transgenic Bt maize’s the nitrogen content of the soil hydrolase at the huge bellbottom stage was signif-icantly higher than the non-transgenic maize,at tasseling and silking stage was significantly lower than the non-transgenic maize.Soil nitrate content of transgenic Bt maize at jointing and tasseling is significantly lower than non-transgenic maize,at maturity has significantly increased.Transgenic Bt maize’s soil ammonium ni-trogen in the the huge bellbottom and tasseling stage is significantly lower than non-transgenic maize.From the jointing stage,in addition to the available phosphorus content of the grain-filling stage,non-genetically modi-fied corn available P and K content was significantly higher than transgenic Bt maize.%试验以转 Bt 基因玉米丹 BT01为研究对象,研究了在大田种植条件下转 Bt 基因玉米对苗期、拔节期、大喇叭口期、抽雄期、灌浆期和成熟期土壤养分含量的影响。结果表明,转 Bt 基因玉米抽雄期和成熟期土壤有机质含量,灌浆期全磷含量,大喇叭口期和成熟期缓效钾含量显著高于非转基因玉米,其余生育时期与非转基因玉米的土壤有机质、全氮、

  19. Mobility of adsorbed Cry1Aa insecticidal toxin from Bacillus thuringiensis (Bt) on montmorillonite measured by fluorescence recovery after photobleaching (FRAP)

    Science.gov (United States)

    Helassa, Nordine; Daudin, Gabrielle; Noinville, Sylvie; Janot, Jean-Marc; Déjardin, Philippe; Staunton, Siobhán; Quiquampoix, Hervé

    2010-06-01

    The insecticidal toxins produced by genetically modified Bt crops are introduced into soil through root exudates and tissue decomposition and adsorb readily on soil components, especially on clays. This immobilisation and the consequent concentration of the toxins in "hot spots" could increase the exposure of soil organisms. Whereas the effects on non-target organisms are well documented, few studies consider the migration of the toxin in soil. In this study, the residual mobility of Bt Cry1Aa insecticidal toxin adsorbed on montmorillonite was assessed using fluorescence recovery after photobleaching (FRAP). This technique, which is usually used to study dynamics of cytoplasmic and membrane molecules in live cells, was applied for the first time to a protein adsorbed on a finely divided swelling clay mineral, montmorillonite. No mobility of adsorbed toxin was observed at any pH and at different degrees of surface saturation.

  20. Insect pests management of bt cotton through the manipulation of different eco-friendly techniques

    International Nuclear Information System (INIS)

    This study was designed to manage insect pests of Bt cotton through the manipulation of different eco-friendly techniques. A perusal of data, based on the overall performance of different treatments reflected that lowest population of jassids (0.29) was observed in bio-control treated Bt cotton followed by bio-control treated conventional cotton (0.41). Mean per leaf population of thrips was found lowest in insecticide treated Bt cotton (0.97) which was statically at par with bi-control treated conventional cotton (0.95), biocontrol treated Bt cotton (1.09) and colour traps treated Bt cotton (1.50). In case of white flies, bio-control treated Bt cotton and bio-control treated conventional cotton again proved effective in maintaining the population at lower levels per leaf (0.33 and 0.35 respectively). No bollworms infestation was recorded in transgenic cotton whereas higher attack of the same was observed in the untreated conventional cotton block. The best results were achieved with the application of bio-control agents in combination with Bt cotton resulting in least infestation by insect pests and maximum seed yield of 3657 kg/ha. The population of Chrysoperla carnea was significantly higher in Bt and conventional cotton treated with bio-control agents as compared to the other treatments. The parasitism percentage of Trichogramma chilonis was observed significantly higher in bio-control treated conventional cotton. The studies manifested that combination of bio-control technology with Bt cotton effectively preserves the local beneficial insect fauna indicating its potential to be used as integrated management system against different insect pests of cotton. (author)

  1. Loading and Light Degradation Characteristics of Bt Toxin on Nanogoethite: A Potential Material for Controlling the Environmental Risk of Bt Toxin

    Directory of Open Access Journals (Sweden)

    Xueyong Zhou

    2015-01-01

    Full Text Available Transgenic Bt-modified crops release toxins into soil through root exudates and upon decomposition of residues. The fate of these toxins in soil has not been yet clearly elucidated. Nanogoethite was found to have a different influence on the lifetime and insecticidal activity of Bt toxin. The aim of this study was to elucidate the adsorption characteristics of Bt toxin on nanogoethite and its activity changes before and after adsorption. The adsorption of toxin on nanogoethite reached equilibrium within 5 h, and the adsorption isotherm of Bt toxin on nanogoethite conformed to the Langmuir equation (R2>0.9690. In the range of pH from 6.0 to 8.0, larger adsorption occurred at lower pH value. The toxin adsorption decreased with the temperature between 10 and 50°C. The results of FTIR, XRD, and SEM indicated that toxin did not influence the structure of nanogoethite and the adsorption of toxin only on the surface of nanogoethite. The LC50 value for bound toxin was higher than that of free toxin, and the nanogoethite greatly accelerated the degradation of toxin by ultraviolet irradiation. The above results suggested that nanogoethite is a potential material for controlling the environmental risk of toxin released by Bt transgenic plants.

  2. Potential Benefits of Bt Brinjal in India — An Economic Assessment

    OpenAIRE

    Kumar, Sant; Lakshmi Prasanna, P.A.; Wankhade, Shwetal

    2011-01-01

    The potential economic benefits of Bt brinjal hybrids in terms of yield gain, reduction in insecticide-use, and increase in net returns per hectare have been reported in this study. Results have shown that adoption of Bt brinjal hybrids would provide yield gain of 37 per cent and reduction in total insecticide-use of about 42 per cent over non-Bt hybrids. Other benefits like increase in additional brinjal production (30 thousand tonnes), savings from insecticides (` 47 crore) against Fruit an...

  3. Introgression of Bt Genes in Novel Germplasm and Contribution to Indian Cotton Economy

    Institute of Scientific and Technical Information of China (English)

    VIDYASAGAR Parchuri

    2008-01-01

    @@ Emergence of transgenic Bt-cotton technology has opened up a new chapter in Indian cotton production in 21st century.The crylAc gene of Monsanto derived from American Upland Coker-312 background was not directly suitable for varied cotton growing situations in India.Delivery of Bt-gene technology to Indian farming systems should be superimposed on hybrid technology,fiber quality,and superior agronomic adaptation.Protection offered by this alien Bt-gene against major serious pest Helicoverpa armigera,by preventing annual losses ranging from 15~35 percent,automaticaly contributed to higher yield.

  4. Risk assessment of Bt crops on the non-target plant-associated insects and soil organisms.

    Science.gov (United States)

    Yaqoob, Amina; Shahid, Ahmad Ali; Samiullah, Tahir Rehman; Rao, Abdul Qayyum; Khan, Muhammad Azmat Ullah; Tahir, Sana; Mirza, Safdar Ali; Husnain, Tayyab

    2016-06-01

    Transgenic plants containing Bacillus thuringiensis (Bt) genes are being cultivated worldwide to express toxic insecticidal proteins. However, the commercial utilisation of Bt crops greatly highlights biosafety issues worldwide. Therefore, assessing the risks caused by genetically modified crops prior to their commercial cultivation is a critical issue to be addressed. In agricultural biotechnology, the goal of safety assessment is not just to identify the safety of a genetically modified (GM) plant, rather to demonstrate its impact on the ecosystem. Various experimental studies have been made worldwide during the last 20 years to investigate the risks and fears associated with non-target organisms (NTOs). The NTOs include beneficial insects, natural pest controllers, rhizobacteria, growth promoting microbes, pollinators, soil dwellers, aquatic and terrestrial vertebrates, mammals and humans. To highlight all the possible risks associated with different GM events, information has been gathered from a total of 76 articles, regarding non-target plant and soil inhabiting organisms, and summarised in the form of the current review article. No significant harmful impact has been reported in any case study related to approved GM events, although critical risk assessments are still needed before commercialisation of these crops. © 2016 Society of Chemical Industry. PMID:26857894

  5. Risk assessment of Bt crops on the non-target plant-associated insects and soil organisms.

    Science.gov (United States)

    Yaqoob, Amina; Shahid, Ahmad Ali; Samiullah, Tahir Rehman; Rao, Abdul Qayyum; Khan, Muhammad Azmat Ullah; Tahir, Sana; Mirza, Safdar Ali; Husnain, Tayyab

    2016-06-01

    Transgenic plants containing Bacillus thuringiensis (Bt) genes are being cultivated worldwide to express toxic insecticidal proteins. However, the commercial utilisation of Bt crops greatly highlights biosafety issues worldwide. Therefore, assessing the risks caused by genetically modified crops prior to their commercial cultivation is a critical issue to be addressed. In agricultural biotechnology, the goal of safety assessment is not just to identify the safety of a genetically modified (GM) plant, rather to demonstrate its impact on the ecosystem. Various experimental studies have been made worldwide during the last 20 years to investigate the risks and fears associated with non-target organisms (NTOs). The NTOs include beneficial insects, natural pest controllers, rhizobacteria, growth promoting microbes, pollinators, soil dwellers, aquatic and terrestrial vertebrates, mammals and humans. To highlight all the possible risks associated with different GM events, information has been gathered from a total of 76 articles, regarding non-target plant and soil inhabiting organisms, and summarised in the form of the current review article. No significant harmful impact has been reported in any case study related to approved GM events, although critical risk assessments are still needed before commercialisation of these crops. © 2016 Society of Chemical Industry.

  6. Study of effects of Bt maize (Zea mays) events on Lepidoptera Ostrinia nubilalis, Sesamia nonagrioidesin southwestern France.

    Science.gov (United States)

    Folcher, L; Eychenne, N; Weissenberger, A; Jarry, M; Regnault-Roger, C; Delos, M

    2006-01-01

    Crops of maize (Zea mays L.) were conducted in southwestern France with GMO (Genetic Modified Organism) vs isogenetic varieties in order to verify the control of European Corn Borer (ECB) Ostrinia nubilalis (Hübner) and the Corn Stalk Borer (CBS) Sesamia nonagrioides (Lefevbre) by GMO in field conditions. The bioassays were carried out in 1998 and 1999 before moratorium, then in 2005. Experiments involved respectively 18, 12 and 19 fields cultivated with Furio/Furio cb (GMO), Cecilia/ Elgina (GMO) and PR33P66/PR33P67 (GMO) varieties. These transgenic events expressed Cry1A(b) protein (Bt maize). Plants were noted for insect infestation assessment (number of larvae in stalks and ears per plant). Statistical tests used t-test on couple of plots. Results showed a significant difference in the density of both ECB and CBS between control and the two transgenic events. The two transgenic events acted differently. The control of the two Bt events on the two pests were differentiated and discussed. These experiments underlined the importance of field evaluation for testing real effects of transgenic events on crop according the environmental context.

  7. Study of effects of Bt maize (Zea mays) events on Lepidoptera Ostrinia nubilalis, Sesamia nonagrioidesin southwestern France.

    Science.gov (United States)

    Folcher, L; Eychenne, N; Weissenberger, A; Jarry, M; Regnault-Roger, C; Delos, M

    2006-01-01

    Crops of maize (Zea mays L.) were conducted in southwestern France with GMO (Genetic Modified Organism) vs isogenetic varieties in order to verify the control of European Corn Borer (ECB) Ostrinia nubilalis (Hübner) and the Corn Stalk Borer (CBS) Sesamia nonagrioides (Lefevbre) by GMO in field conditions. The bioassays were carried out in 1998 and 1999 before moratorium, then in 2005. Experiments involved respectively 18, 12 and 19 fields cultivated with Furio/Furio cb (GMO), Cecilia/ Elgina (GMO) and PR33P66/PR33P67 (GMO) varieties. These transgenic events expressed Cry1A(b) protein (Bt maize). Plants were noted for insect infestation assessment (number of larvae in stalks and ears per plant). Statistical tests used t-test on couple of plots. Results showed a significant difference in the density of both ECB and CBS between control and the two transgenic events. The two transgenic events acted differently. The control of the two Bt events on the two pests were differentiated and discussed. These experiments underlined the importance of field evaluation for testing real effects of transgenic events on crop according the environmental context. PMID:17390797

  8. Bt Maize Seed Mixtures for Helicoverpa zea (Lepidoptera: Noctuidae): Larval Movement, Development, and Survival on Non-transgenic Maize.

    Science.gov (United States)

    Burkness, Eric C; Cira, T M; Moser, S E; Hutchison, W D

    2015-12-01

    In 2012 and 2013, field trials were conducted near Rosemount, MN, to assess the movement and development of Helicoverpa zea (Boddie) larvae on non-Bt refuge corn plants within a seed mixture of non-Bt and Bt corn. The Bt corn hybrid expressed three Bt toxins-Cry1Ab, Cry1F, and Vip3A. As the use of seed mixtures for insect resistance management (IRM) continues to be implemented, it is necessary to further characterize how this IRM approach impacts resistance development in ear-feeding Lepidopteran pests. The potential for Bt pollen movement and cross pollination of the non-Bt ears in a seed mixture may lead to Bt toxin exposure to larvae developing on those refuge ears. Larval movement and development by H. zea, feeding on non-Bt refuge plants adjacent to either transgenic Bt or non-Bt plants, were measured to investigate the potential for unintended Bt exposure. Non-Bt plants were infested with H. zea eggs and subplots were destructively sampled twice per week within each treatment to assess larval development, location, and kernel injury. Results indicate that H. zea larval movement between plants is relatively low, ranging from 2-16% of larvae, and occurs mainly after reaching the second instar. Refuge plants in seed mixtures did not produce equivalent numbers of H. zea larvae, kernel injury, and larval development differed as compared with a pure stand of non-Bt plants. This suggests that there may be costs to larvae developing on refuge plants within seed mixtures and additional studies are warranted to define potential impacts.

  9. Bt Maize Seed Mixtures for Helicoverpa zea (Lepidoptera: Noctuidae): Larval Movement, Development, and Survival on Non-transgenic Maize.

    Science.gov (United States)

    Burkness, Eric C; Cira, T M; Moser, S E; Hutchison, W D

    2015-12-01

    In 2012 and 2013, field trials were conducted near Rosemount, MN, to assess the movement and development of Helicoverpa zea (Boddie) larvae on non-Bt refuge corn plants within a seed mixture of non-Bt and Bt corn. The Bt corn hybrid expressed three Bt toxins-Cry1Ab, Cry1F, and Vip3A. As the use of seed mixtures for insect resistance management (IRM) continues to be implemented, it is necessary to further characterize how this IRM approach impacts resistance development in ear-feeding Lepidopteran pests. The potential for Bt pollen movement and cross pollination of the non-Bt ears in a seed mixture may lead to Bt toxin exposure to larvae developing on those refuge ears. Larval movement and development by H. zea, feeding on non-Bt refuge plants adjacent to either transgenic Bt or non-Bt plants, were measured to investigate the potential for unintended Bt exposure. Non-Bt plants were infested with H. zea eggs and subplots were destructively sampled twice per week within each treatment to assess larval development, location, and kernel injury. Results indicate that H. zea larval movement between plants is relatively low, ranging from 2-16% of larvae, and occurs mainly after reaching the second instar. Refuge plants in seed mixtures did not produce equivalent numbers of H. zea larvae, kernel injury, and larval development differed as compared with a pure stand of non-Bt plants. This suggests that there may be costs to larvae developing on refuge plants within seed mixtures and additional studies are warranted to define potential impacts. PMID:26318006

  10. Natural refuge crops, buildup of resistance, and zero-refuge strategy for Bt cotton in China

    Institute of Scientific and Technical Information of China (English)

    ROZELLE; Scott; WILEN; James

    2010-01-01

    In the context of genetically modified crops expressing the Bacillus thuringiensis (Bt) toxin, a ‘refuge’ refers to a crop of the same or a related species that is planted nearby to enable growth and reproduction of the target pest without the selection pres- sure imposed by the Bt toxin. The goal of this study is to discuss the role of natural refuge crops in slowing down the buildup of resistance of cotton bollworm (CBW), and to evaluate China’s no-refuge policy for Bt cotton. We describe in detail the dif- ferent factors that China should consider in relation to the refuge policy. Drawing on a review of scientific data, economic analyses of other cases, and a simulation exercise using a bio-economic model, we show that in the case of Bt cotton in China, the no-refuge policy is defensible.

  11. Impact of Bt crops on non-target organisms – 3 systematic reviews

    Science.gov (United States)

    The cultivation of genetically modified (GM) crops producing Cry toxins, originating from the bacterium Bacillus thuringiensis (Bt), has raised environmental concerns over their sustainable use and consequences for biodiversity and ecosystem services in agricultural land. During the last two decades...

  12. Test Takers' Writing Activities during the "TOEFL iBT"® Writing Tasks: A Stimulated Recall Study. "TOEFL iBT"® Research Report. TOEFL iBT-25. ETS Research Report No. RR-15-04

    Science.gov (United States)

    Barkaoui, Khaled

    2015-01-01

    This study aimed to describe the writing activities that test takers engage in when responding to the writing tasks in the "TOEFL iBT"[superscript R] test and to examine the effects of task type and test-taker English language proficiency (ELP) and keyboarding skills on the frequency and distribution of these activities. Each of 22 test…

  13. Chronic Responses of Daphnia magna Under Dietary Exposure to Leaves of a Transgenic (Event MON810) Bt-Maize Hybrid and its Conventional Near-Isoline.

    Science.gov (United States)

    Holderbaum, Daniel Ferreira; Cuhra, Marek; Wickson, Fern; Orth, Afonso Inácio; Nodari, Rubens Onofre; Bøhn, Thomas

    2015-01-01

    Insect resistance is the second most common trait globally in cultivated genetically modified (GM) plants. Resistance is usually obtained by introducing into the plant's genome genes from the bacterium Bacillus thuringiensis (Bt) coding for insecticidal proteins (Cry proteins or toxins) that target insect pests. The aim of this study was to examine the hypothesis that a chronic, high-dose dietary exposure to leaves of a Bt-maize hybrid (GM event MON810, expressing a transgenic or recombinant Cry1Ab toxin), exerted no adverse effects on fitness parameters of the aquatic nontarget organism Daphnia magna (water flea) when compared to an identical control diet based on leaves of the non-GM near-isoline. Cry1Ab was immunologically detected and quantified in GM maize leaf material used for Daphnia feed. A 69-kD protein near Bt's active core-toxin size and a 34-kD protein were identified. The D. magna bioassay showed a resource allocation to production of resting eggs and early fecundity in D. magna fed GM maize, with adverse effects for body size and fecundity later in life. This is the first study to examine GM-plant leaf material in the D. magna model, and provides of negative fitness effects of a MON810 maize hybrid in a nontarget model organism under chronic, high dietary exposure. Based upon these results, it is postulated that the observed transgenic proteins exert a nontarget effect in D. magna and/or unintended changes were produced in the maize genome/metabolome by the transformation process, producing a nutritional difference between GM-maize and non-GM near-isoline. PMID:26262442

  14. Adoption of Bt Cotton: Threats and Challenges Adopción de Algodón Bt: Desafíos y Amenazas

    OpenAIRE

    Muhammad Faisal Bilal; Muhammad Farrukh Saleem; Muhammad Ashfaq Wahid; Amir Shakeel; Mudassar Maqbool

    2012-01-01

    Adopting new technology always involves advantages and risks; Bt cotton (Gossypium hirsutum L.) is a new technology well known in developed countries for its many advantages, such as reduced pesticide application, better insect pest control, and higher lint yield. However, its success in developing countries is still a question mark. Global adoption of Bt cotton has risen dramatically from 0.76 million ha when introduced in 1996 to 7.85 million ha in the 2005 cotton-growing season where 54% o...

  15. A decade of Bt cotton in Chinese fields: Assessing the direct effects and indirect externalities of Bt cotton adoption in China

    Institute of Scientific and Technical Information of China (English)

    Scott; ROZELLE; Carl; PRAY

    2010-01-01

    The objective of this study is to examine whether or not the gains from reduced spraying for bollworms are being sustained more than one decade after the initial adoption in 2007. Based on farm-level data collected by the authors in 1999–2007 in 16 villages from 4 provinces, this study shows that insecticides applied for controlling bollworms have declined. This analysis supports Chinese policy makers’ decision to not require refuges of non-Bt cotton fields. It also suggests that past studies may have underestimated the benefits from adopting Bt technology.

  16. Adoption of Bt Cotton: Threats and Challenges Adopción de Algodón Bt: Desafíos y Amenazas

    Directory of Open Access Journals (Sweden)

    Muhammad Faisal Bilal

    2012-09-01

    Full Text Available Adopting new technology always involves advantages and risks; Bt cotton (Gossypium hirsutum L. is a new technology well known in developed countries for its many advantages, such as reduced pesticide application, better insect pest control, and higher lint yield. However, its success in developing countries is still a question mark. Global adoption of Bt cotton has risen dramatically from 0.76 million ha when introduced in 1996 to 7.85 million ha in the 2005 cotton-growing season where 54% of the cotton crops in the USA, 76% in China, and 80% in Australia were grown with single or multiple Bt genes. Bollworms are serious cotton pests causing 30-40% yield reduction in Pakistan and 20-66% potential crop losses in India. The major advances shown in this review include: (1 Evolution of Bt cotton may prove to be a green revolution to enhance cotton yield; (2 adoption of Bt cotton by farmers is increasing due to its beneficial environmental effects by reducing pesticide application: however, a high seed price has compelled farmers to use illegal non-approved Bt causing huge damage to crops because of low tolerance to insect pests; and (3 some factors responsible for changes in the efficiency of the Bt gene and Bt cotton yield include internal phenology (genetics, atmospheric changes (CO2 concentration, nutrition, insect pests, boll distribution pattern, disease and nematodes, removal of fruiting branch and/or floral bud, introduction of Bt gene, and terpenoids and tannin production in the plant body.La adopción de nueva tecnología siempre involucra ventajas y riesgos; algodón Bt (Gossypium hirsutum L. es una nueva tecnología bien conocida en países desarrollados por muchas ventajas como reducida aplicación de pesticidas, mejor control de insectos plaga, y mayor producción de fibra, pero su éxito en países en desarrollo aún conlleva dudas. La adopción global de algodón Bt ha aumentado dramáticamente de 0,76 millones de hectáreas en su

  17. Research on Chip's Deform in Cryonic Cutting BT20 Titanium Alloy%BT20钛合金低温切屑变形的研究

    Institute of Scientific and Technical Information of China (English)

    魏树国; 马光锋; 钱宇强

    2005-01-01

    金属切屑变形过程的研究,对切削加工技术的发展有很大的影响.BT20钛合金是典型的难加工材料,针对切削加工性差的原因采用低温切削改善其切削加工性,试验证明低温切削是改善BT20钛合金切屑变形的有效加工方法.

  18. Evidence of Field-Evolved Resistance of Spodoptera frugiperda to Bt Corn Expressing Cry1F in Brazil That Is Still Sensitive to Modified Bt Toxins

    OpenAIRE

    Rose Monnerat; Erica Martins; Cristina Macedo; Paulo Queiroz; Lilian Praça; Carlos Marcelo Soares; Helio Moreira; Isabella Grisi; Joseane Silva; Mario Soberon; Alejandra Bravo

    2015-01-01

    Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold highe...

  19. Is Monsanto Leaving Money on the Table? Monopoly Pricing and Bt Cotton Value with Heterogeneous Adopters

    OpenAIRE

    Oehmke, James F.; Wolf, Christopher A.

    2004-01-01

    We examine the allocation of technology rents between a price-setting, innovating monopolist and heterogeneous technology adopters. A model of monopoly pricing in the presence of heterogeneous adopters is used to examine conditions under which greater producer (farmer) heterogeneity leads to greater producer benefit from innovation in non-competitive markets. An application to Bt cotton determines the profit-maximizing price of Bt cotton seed and reveals that Monsanto and Delta and Pine Land ...

  20. Competitive release and outbreaks of non-target pests associated with transgenic Bt cotton.

    Science.gov (United States)

    Zeilinger, Adam R; Olson, Dawn M; Andow, David A

    2016-06-01

    The adoption of transgenic Bt cotton has, in some cases, led to environmental and economic benefits through reduced insecticide use. However, the distribution of these benefits and associated risks among cotton growers and cotton-growing regions has been uneven due in part to outbreaks of non-target or secondary pests, thereby requiring the continued use of synthetic insecticides. In the southeastern USA, Bt cotton adoption has resulted in increased abundance of and damage from stink bug pests, Euschistus servus and Nezara viridula (Heteroptera: Pentatomidae). While the impact of increased stink bug abundance has been well-documented, the causes have remained unclear. We hypothesize that release from competition with Bt-susceptible target pests may drive stink bug outbreaks in Bt cotton. We first examined the evidence for competitive release of stink bugs through meta-analysis of previous studies. We then experimentally tested if herbivory by Bt-susceptible Helicoverpa zea increases stink bug leaving rates and deters oviposition on non-Bt cotton. Consistent with previous studies, we found differences in leaving rates only for E servus, but we found that both species strongly avoided ovipositing on H. zea-damaged plants. Considering all available evidence, competitive release of stink bug populations in Bt cotton likely contributes to outbreaks, though the relative importance of competitive release remains an open question. Ecological risk assessments of Bt crops and other transgenic insecticidal crops would benefit from greater understanding of the ecological mechanisms underlying non-target pest outbreaks and greater attention to indirect ecological effects more broadly.

  1. Competitive release and outbreaks of non-target pests associated with transgenic Bt cotton.

    Science.gov (United States)

    Zeilinger, Adam R; Olson, Dawn M; Andow, David A

    2016-06-01

    The adoption of transgenic Bt cotton has, in some cases, led to environmental and economic benefits through reduced insecticide use. However, the distribution of these benefits and associated risks among cotton growers and cotton-growing regions has been uneven due in part to outbreaks of non-target or secondary pests, thereby requiring the continued use of synthetic insecticides. In the southeastern USA, Bt cotton adoption has resulted in increased abundance of and damage from stink bug pests, Euschistus servus and Nezara viridula (Heteroptera: Pentatomidae). While the impact of increased stink bug abundance has been well-documented, the causes have remained unclear. We hypothesize that release from competition with Bt-susceptible target pests may drive stink bug outbreaks in Bt cotton. We first examined the evidence for competitive release of stink bugs through meta-analysis of previous studies. We then experimentally tested if herbivory by Bt-susceptible Helicoverpa zea increases stink bug leaving rates and deters oviposition on non-Bt cotton. Consistent with previous studies, we found differences in leaving rates only for E servus, but we found that both species strongly avoided ovipositing on H. zea-damaged plants. Considering all available evidence, competitive release of stink bug populations in Bt cotton likely contributes to outbreaks, though the relative importance of competitive release remains an open question. Ecological risk assessments of Bt crops and other transgenic insecticidal crops would benefit from greater understanding of the ecological mechanisms underlying non-target pest outbreaks and greater attention to indirect ecological effects more broadly. PMID:27509747

  2. The adoption of Bt-maize in Germany: An econometric analysis

    OpenAIRE

    Consmuller, Nicola; Beckmann, Volker; Petrick, Martin

    2009-01-01

    In this study, we theoretically and empirically investigate the determinants of Bt-maize adoption in German regions. Specifically, we ask how the regulatory framework, the farm structures as well as the socio-political environment of GM expansion in Germany have influenced regional adoption rates. Following a description of the relevant legal and economic framework in Germany, we develop theoretical hypotheses concerning regional variation in Bt-maize adoption and test them econometrically wi...

  3. The emergence of insect resistance in Bt-corn: implication of resistance management information under uncertainty

    OpenAIRE

    Linacre, Nicholas A.; Thompson, Colin J.

    2005-01-01

    "The successful management of transgenic technology is likely to depend on the economic behavioral response of farmers to the regulated use of transgenic crops. A well-studied example is the widespread use of Bt-corn, in the United States, and elsewhere, to control the European Corn Borer, a major corn pest. The extensive use of Bt-corn has led to concerns about the emergence of insect resistance. The United States Environment Protection Agency addressed this potential problem by developing a...

  4. Early Detection and Mitigation of Resistance to Bt Maize by Western Corn Rootworm (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Andow, David A; Pueppke, Steven G; Schaafsma, Arthur W; Gassmann, Aaron J; Sappington, Thomas W; Meinke, Lance J; Mitchell, Paul D; Hurley, Terrance M; Hellmich, Richard L; Porter, R Pat

    2016-02-01

    Transgenic Bt maize that produces less than a high-dose has been widely adopted and presents considerable insect resistance management (IRM) challenges. Western corn rootworm, Diabrotica virgifera virgifera LeConte, has rapidly evolved resistance to Bt maize in the field, leading to local loss of efficacy for some corn rootworm Bt maize events. Documenting and responding to this resistance has been complicated by a lack of rapid diagnostic bioassays and by regulatory triggers that hinder timely and effective management responses. These failures are of great concern to the scientific and agricultural community. Specific challenges posed by western corn rootworm resistance to Bt maize, and more general concerns around Bt crops that produce less than a high-dose of Bt toxin, have caused uncertainty around current IRM protocols. More than 15 years of experience with IRM has shown that high-dose and refuge-based IRM is not applicable to Bt crops that produce less than a high-dose. Adaptive IRM approaches and pro-active, integrated IRM-pest management strategies are needed and should be in place before release of new technologies that produce less than a high-dose. We suggest changes in IRM strategies to preserve the utility of corn rootworm Bt maize by 1) targeting local resistance management earlier in the sequence of responses to resistance and 2) developing area-wide criteria to address widespread economic losses. We also favor consideration of policies and programs to counteract economic forces that are contributing to rapid resistance evolution. PMID:26362989

  5. Development of Insect-Resistant Hybrid Rice by Introgressing the Bt Gene from Bt Rice Huahui 1 into II-32A/B, a Widely Used Cytogenic Male Sterile System

    Institute of Scientific and Technical Information of China (English)

    LAI Yun-song; HUANG Hai-qing; XU Meng-yun; WANG Liang-chao; ZHANG Xiao-bo; ZHANG Ji-wen; TU Ju-min

    2014-01-01

    Huahui 1 is an elite transgenic male sterile restorer line of wild rice abortive-type that expresses a Bacillus thuringiensis (Bt)δ-endotoxin and provides effective and economic control of lepidopteran insects. To exploit Huahui 1 to develop a new Bt rice, the insertion site of the Bt gene was determined by thermal asymmetric interlaced PCR (TAIL-PCR). Bt was located in the promoter region of LOC.Os10g10360, approximately 5.35 Mb from the telomere of the short arm of chromosome 10. For the ifrst time, a Bt cytoplasmic male sterile (CMS) system was developed by int