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da Silva Nunes G, de Souza JM, Ramalho DG, De Bortoli SA, Polanczyk RA. Bacillus thuringiensis-based bioinsecticides affect predation of Euborellia annulipes on diamondback moth larvae. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:90730-90740. [PMID: 37462876 DOI: 10.1007/s11356-023-28814-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/12/2023] [Indexed: 08/24/2023]
Abstract
Interactions between earwigs and entomopathogens, such as Bacillus thuringiensis (Bt), are still poorly understood. This study tested whether Bt-based bioinsecticides have any effect on the predation of Euborellia annulipes (Lucas) (Dermaptera: Anisolabididae) on Plutella xylostella (L.) (Lepidoptera: Plutellidae), one of the pests with the largest number of cases of use and resistance to Bt. Fourth instar larvae were Bt infected by feeding on collard green leaves treated with Dipel®WG and XenTari®WG at the manufacturer-recommended doses. We used one no-choice condition, in which the predator had access to uninfected or Bt-infected larvae separately, and four free-choice conditions: uninfected vs Dipel®-infected larvae, uninfected vs XenTari®-infected larvae, Dipel®-infected vs XenTari®-infected larvae, and uninfected vs Bt-infected larvae with both bioinsecticides. Uninfected larvae were less consumed than those infected by both Bt-bioinsecticides in the no-choice condition. There was a higher consumption of uninfected over Dipel®-infected larvae in the free-choice condition. Overall, uninfected larvae were preferred over both Bt-based bioinsecticides infected larvae. We also used six different prey densities. The ringlegged earwig's predation rate enhanced as the prey population density increased, but the functional response was not affected by Bt-infection, being type II. The predator invested a low amount of handling time on Bt-fed prey and increased the maximum predation rate. Bt-based bioinsecticides cause effects on E. annulipes predation by altering their feeding preference and some aspects of its predatory behavior. The results of our study provide an important background for understanding interactions between earwigs and Bt. In addition, they can be used for decision making during approaches to integrated P. xylostella management.
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Affiliation(s)
- Gilmar da Silva Nunes
- Instituto Federal Goiano, Rodovia Sul Goiana, km 01, Zona Rural, CEP, Rio Verde, GO, 75901-970, Brazil.
| | - Joice Mendonça de Souza
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
| | - Dagmara Gomes Ramalho
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
| | - Sergio Antonio De Bortoli
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
| | - Ricardo Antonio Polanczyk
- Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castelane, CEP, Jaboticabal, SP, 14884-900, Brazil
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Wang Z, Shea Z, Rosso L, Shang C, Li J, Bewick P, Li Q, Zhao B, Zhang B. Development of new mutant alleles and markers for KTI1 and KTI3 via CRISPR/Cas9-mediated mutagenesis to reduce trypsin inhibitor content and activity in soybean seeds. FRONTIERS IN PLANT SCIENCE 2023; 14:1111680. [PMID: 37223818 PMCID: PMC10200896 DOI: 10.3389/fpls.2023.1111680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/31/2023] [Indexed: 05/25/2023]
Abstract
The digestibility of soybean meal can be severely impacted by trypsin inhibitor (TI), one of the most abundant anti-nutritional factors present in soybean seeds. TI can restrain the function of trypsin, a critical enzyme that breaks down proteins in the digestive tract. Soybean accessions with low TI content have been identified. However, it is challenging to breed the low TI trait into elite cultivars due to a lack of molecular markers associated with low TI traits. We identified Kunitz trypsin inhibitor 1 (KTI1, Gm01g095000) and KTI3 (Gm08g341500) as two seed-specific TI genes. Mutant kti1 and kti3 alleles carrying small deletions or insertions within the gene open reading frames were created in the soybean cultivar Glycine max cv. Williams 82 (WM82) using the CRISPR/Cas9-mediated genome editing approach. The KTI content and TI activity both remarkably reduced in kti1/3 mutants compared to the WM82 seeds. There was no significant difference in terms of plant growth or maturity days of kti1/3 transgenic and WM82 plants in greenhouse condition. We further identified a T1 line, #5-26, that carried double homozygous kti1/3 mutant alleles, but not the Cas9 transgene. Based on the sequences of kti1/3 mutant alleles in #5-26, we developed markers to co-select for these mutant alleles by using a gel-electrophoresis-free method. The kti1/3 mutant soybean line and associated selection markers will assist in accelerating the introduction of low TI trait into elite soybean cultivars in the future.
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Affiliation(s)
- Zhibo Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Zachary Shea
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Luciana Rosso
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Chao Shang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Jianyong Li
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, United States
| | - Patrick Bewick
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Qi Li
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Bingyu Zhao
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Bo Zhang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
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Guo M, Wang Z, Cai W, Hua H, Zhao J. Safety assessment of transgenic Cry2Aa rice to a generalist predator, Paederus fuscipes Curtis (Coleoptera: Staphylinidae). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 200:110719. [PMID: 32460046 DOI: 10.1016/j.ecoenv.2020.110719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 04/27/2020] [Accepted: 05/10/2020] [Indexed: 06/11/2023]
Abstract
The insecticidal crystal proteins of Cry2A family from Bacillus thuringiensis (Bt) are important candidate proteins expressed in gene pyramiding Bt crops. A transgenic rice line (T2A-1) harboring a synthetic Cry2A* (Cry2Aa) gene showed effective resistance to some lepidopteran rice pests. As a generalist predator in rice ecosystems, the rove beetle (Paederus fuscipes) can prey on many rice insect pests such as planthoppers. Considering the possible exposure of Cry2Aa to P. fuscipes through tritrophic food chain, it is necessary to assess the potential risks of T2A-1 rice to this predator. In this study, a tritrophic experiment was conducted to assess the prey-mediated effects of Cry2Aa on P. fuscipes through the T2A-1 rice-Nilaparvata lugens-P. fuscipes food chain. After preying on N. lugens nymphs reared on T2A-1, no accumulated Cry2Aa could be detected in P. fuscipes adults, despite Cry2Aa being detected in N. lugens. In addition, no harmful effects were detected on the life table parameters of P. fuscipes in this tritrophic chain. Additionally, direct exposure to a high dose of purified Cry2Aa protein, representing the worst case scenario, showed no significant adverse effects on the development of P. fuscipes. These results showed that transgenic Cry2Aa rice had no harmful effects on P. fuscipes.
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Affiliation(s)
- Mengjian Guo
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhengjie Wang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wanlun Cai
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hongxia Hua
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jing Zhao
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
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Buhl C, Meilan R, Lindroth RL. Genetic Modification of Lignin in Hybrid Poplar (Populus alba × Populus tremula) Does Not Substantially Alter Plant Defense or Arthropod Communities. JOURNAL OF INSECT SCIENCE (ONLINE) 2017; 17:3858857. [PMID: 28973575 PMCID: PMC5538326 DOI: 10.1093/jisesa/iex052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Indexed: 06/07/2023]
Abstract
Lignin impedes access to cellulose during biofuel production and pulping but trees can be genetically modified to improve processing efficiency. Modification of lignin may have nontarget effects on mechanical and chemical resistance and subsequent arthropod community responses with respect to pest susceptibility and arthropod biodiversity. We quantified foliar mechanical and chemical resistance traits in lignin-modified and wild-type (WT) poplar (Populus alba × Populus tremula) grown in a plantation and censused arthropods present on these trees to determine total abundance, as well as species richness, diversity and community composition. Our results indicate that mechanical resistance was not affected by lignin modification and only one genetic construct resulted in a (modest) change in chemical resistance. Arthropod abundance and community composition were consistent across modified and WT trees, but transgenics produced using one construct exhibited higher species richness and diversity relative to the WT. Our findings indicate that modification of lignin in poplar does not negatively affect herbivore resistance traits or arthropod community response, and may even result in a source of increased genetic diversity in trees and arthropod communities.
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Affiliation(s)
- Christine Buhl
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706 (; )
- Current address: 2600 State St., Salem, OR 97310
| | - Richard Meilan
- Department of Forestry and Natural Resources, Purdue University, 715 W. State St., West Lafayette, IN 47907 ()
| | - Richard L. Lindroth
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706 (; )
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Van Den Berg J, Warren JF, Du Plessis H. The Potential Effect of Bt Maize on Chrysoperla pudica (Neuroptera: Chrysopidae). ENVIRONMENTAL ENTOMOLOGY 2017; 46:413-417. [PMID: 28334097 DOI: 10.1093/ee/nvx045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 01/27/2017] [Indexed: 06/06/2023]
Abstract
Previous studies into third trophic level exposure of Chrysoperla spp. (Neuroptera: Chrysopidae) to Cry1Ab proteins produced by Bt crops yielded contradicting results. These contradictions were largely ascribed to differences in prey quality and exposure methods. In this study, we used healthy prey to expose lacewing larvae to Cry1Ab protein produced by Bt maize, and also determined the concentration of this protein at different trophic levels. Experiments were conducted in which Chrysoperla pudica (Navás) larvae were fed different diets which included aphids and healthy Bt-resistant Busseola fusca (Fuller) (Lepidoptera: Noctuidae) larvae feeding on Bt maize tissue. Lacewing larval and pupal development times as well as overall mortality were determined. The concentration of Cry1Ab protein in B. fusca larvae were fourfold reduced compared with that in leaf tissue and was below detection level in lacewing larvae. Survival to the pupal stage was higher than 96% in all treatments. Larval and pupal development periods did not differ significantly between treatments in which prey fed on Bt or non-Bt maize. This study showed feeding on healthy prey that consumed Cry1Ab protein has no adverse effect on the biology of C. pudica.
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Affiliation(s)
- J Van Den Berg
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa (; ; )
| | - J F Warren
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa (; ; )
| | - H Du Plessis
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa (; ; )
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Sun X, Zhou W, Liu H, Zhang A, Ai CR, Zhou SS, Zhou CX, Wang MQ. Transgenic Bt rice does not challenge host preference of the target pest of rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae). PLoS One 2013; 8:e79032. [PMID: 24244410 PMCID: PMC3823965 DOI: 10.1371/journal.pone.0079032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 09/17/2013] [Indexed: 11/20/2022] Open
Abstract
Background Transgenic Bt rice line T2A-1 expresses a synthesized cry2A gene that shows high resistance to Lepidoptera pests, including Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). Plant volatile orientation cues and the physical characteristics of the leaf surface play key roles in host location or host-plant acceptance of phytophagous insects. These volatile compounds and physical traits may become altered in Bt rice and it is not known whether this influences the behavior of C. medinalis when searching for oviposition sites. Results The results of electronic nose analysis showed that the Radar map of Bt rice cultivars was analogous to the non- Bt rice cultivars at each growing stage. PCA analysis was able to partly discriminate between some of the Bt vs. non-Bt rice sensors, but could not to separate Bt cultivars from non-Bt cultivars. The total ion chromatogram between Bt and non-Bt rice cultivars at the seedling, booting and tillering stages were similar and 25 main compounds were identified by GC-MS. For most compounds, there was no significant difference in compound quantities between Bt and non-Bt rice cultivars at equivalent growth stages. The densities of the tubercle papicles and the trichomes on the upper and lower surfaces were statistically equal in Bt and non-Bt rice. The target pest, C. medinalis, was attracted to host rice plants, but it could not distinguish between the transgenic and the isogenic rice lines. Conclusions There were no significant differences between the Bt rice line, T2A-1 and the non-Bt rice for volatiles produced or in its physical characteristics and there were no negative impacts on C. medinalis oviposition behavior. These results add to the mounting evidence that Bt rice has no negative impact on the target insect oviposition behavior.
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Affiliation(s)
- Xiao Sun
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Wen Zhou
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Hao Liu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Aijun Zhang
- Invasive Insect Biocontrol and Behavior Laboratory, United States Department of Agriculture-Agricultural Research Service, Beltsville, Maryland, United States of America
| | - Chao-Ren Ai
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Shuang-Shuang Zhou
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Chang-Xiang Zhou
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Man-Qun Wang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
- * E-mail:
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Peñaflor MFGV, Bento JMS. Herbivore-induced plant volatiles to enhance biological control in agriculture. NEOTROPICAL ENTOMOLOGY 2013; 42:331-43. [PMID: 23949852 DOI: 10.1007/s13744-013-0147-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 05/31/2013] [Indexed: 05/02/2023]
Abstract
Plants under herbivore attack synthetize defensive organic compounds that directly or indirectly affect herbivore performance and mediate other interactions with the community. The so-called herbivore-induced plant volatiles (HIPVs) consist of odors released by attacked plants that serve as important cues for parasitoids and predators to locate their host/prey. The understanding that has been gained on the ecological role and mechanisms of HIPV emission opens up paths for developing novel strategies integrated with biological control programs with the aim of enhancing the efficacy of natural enemies in suppressing pest populations in crops. Tactics using synthetic HIPVs or chemically/genetically manipulating plant defenses have been suggested in order to recruit natural enemies to plantations or help guiding them to their host more quickly, working as a "synergistic" agent of biological control. This review discusses strategies using HIPVs to enhance biological control that have been proposed in the literature and were categorized here as: (a) exogenous application of elicitors on plants, (b) use of plant varieties that emit attractive HIPVs to natural enemies, (c) release of synthetic HIPVs, and (d) genetic manipulation targeting genes that optimize HIPV emission. We discuss the feasibility, benefits, and downsides of each strategy by considering not only field studies but also comprehensive laboratory assays that present an applied approach for HIPVs or show the potential of employing them in the field.
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Affiliation(s)
- M F G V Peñaflor
- Depto de Entomologia e Acarologia, Univ de São Paulo, ESALQ/USP, Av. Pádua Dias, 11, CP 9, 13418-900, Piracicaba, SP, Brasil
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Hansen LS, Lövei GL, Székács A. Survival and development of a stored-product pest, Sitophilus zeamais (Coleoptera: Curculionidae), and its natural enemy, the parasitoid Lariophagus distinguendus (Hymenoptera: Pteromalidae), on transgenic Bt maize. PEST MANAGEMENT SCIENCE 2013; 69:602-606. [PMID: 23044867 DOI: 10.1002/ps.3410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 08/07/2012] [Accepted: 08/21/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND The effect of transgenic maize (Zea mays L.) containing a lepidopteran-specific Bt toxin on a stored-product pest, Sitophilus zeamais Motschulsky, and its parasitoid, Lariophagus distinguendus Förster, was examined in the laboratory to test the impact of transgenic maize on stored-product pests and their biological control. RESULTS Weevils were not harmfully affected by transgenic Bt maize in their development characteristics (development time, body mass), and females emerging from transgenic maize kernels were larger. However, significantly fewer parasitoid females emerged from weevils that developed in transgenic kernels, although parasitoids did not develop more slowly and were not different in size or mass from their conspecifics emerging from hosts in non-transgenic maize kernels. CONCLUSION The emergence of female parasitoids was reduced in transgenic Bt maize, and this effect cannot be explained by the known lepidopteran-specific toxicity of Bt Cry1Ab toxin.
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Affiliation(s)
- Lise S Hansen
- Department of Agroecology, Aarhus University, Flakkebjerg, Slagelse, Denmark.
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Abstract
Rice is the most important food crops in maintaining food security in China. The loss of China's annual rice production caused by pests is over ten million tons. Present studies showed that the transgenic insect-resistant rice can substantially reduce the application amount of chemical pesticides. In the case of no pesticide use, the pest density in transgenic rice field is significantly lower than that in non-transgenic field, and the neutral insects and natural enemies of pests increased significantly, indicating that the ecological environment and biodiversity toward the positive direction. The gene flow frequency from transgenic rice is dramatically reduced with the distance increases, reaching less than 0.01% at the distance of 6.2 m. Application of transgenic insect-resistant rice in China has an important significance for ensuring food security, maintaining sustainable agricultural development, and protecting the ecological environment and biodiversity. This review summarized the research progress in transgenic insect-resistant rice and its effect on biodiversity. The research directions and development trends of crop pest controlling in future are discussed. These help to promote better use of transgenic insect-resistant rice.
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Jensen PD, Dively GP, Swan CM, Lamp WO. Exposure and nontarget effects of transgenic Bt corn debris in streams. ENVIRONMENTAL ENTOMOLOGY 2010; 39:707-14. [PMID: 20388306 DOI: 10.1603/en09037] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
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.
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Affiliation(s)
- Peter D Jensen
- Integral Consulting, Annapolis, 200 Harry S Truman Parkway, MD 21401, USA
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Himanen SJ, Nerg AM, Nissinen A, Pinto DM, Stewart CN, Poppy GM, Holopainen JK. Effects of elevated carbon dioxide and ozone on volatile terpenoid emissions and multitrophic communication of transgenic insecticidal oilseed rape (Brassica napus). THE NEW PHYTOLOGIST 2009; 181:174-186. [PMID: 19076723 DOI: 10.1111/j.1469-8137.2008.02646.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Does transgenically incorporated insect resistance affect constitutive and herbivore-inducible terpenoid emissions and multitrophic communication under elevated atmospheric CO(2) or ozone (O(3))? This study aimed to clarify the possible interactions between allocation to direct defences (Bacillus thuringiensis (Bt) toxin production) and that to endogenous indirect defences under future climatic conditions. Terpenoid emissions were measured from vegetative-stage non-Bt and Bt Brassica napus grown in growth chambers under control or doubled CO(2), and control (filtered air) or 100 ppb O(3). The olfactometric orientation of Cotesia vestalis, an endoparasitoid of the herbivorous diamondback moth (Plutella xylostella), was assessed under the corresponding CO(2) and O(3) concentrations. The response of terpenoid emission to CO(2) or O(3) elevations was equivalent for Bt and non-Bt plants, but lower target herbivory reduced herbivore-inducible emissions from Bt plants. Elevated CO(2) increased emissions of most terpenoids, whereas O(3) reduced total terpenoid emissions. Cotesia vestalis orientated to host-damaged plants independent of plant type or CO(2) concentration. Under elevated O(3), host-damaged non-Bt plants attracted 75% of the parasitoids, but only 36.8% of parasitoids orientated to host-damaged Bt plants. Elevated O(3) has the potential to perturb specialized food-web communication in Bt crops.
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Affiliation(s)
- Sari J Himanen
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen, Finland;Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA;School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
| | - Anne-Marja Nerg
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen, Finland;Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA;School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
| | - Anne Nissinen
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen, Finland;Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA;School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
| | - Delia M Pinto
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen, Finland;Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA;School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
| | - C Neal Stewart
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen, Finland;Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA;School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
| | - Guy M Poppy
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen, Finland;Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA;School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
| | - Jarmo K Holopainen
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland;MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen, Finland;Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA;School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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Himanen SJ, Nerg AM, Nissinen A, Stewart CN, Poppy GM, Holopainen JK. 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. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2009; 157:181-185. [PMID: 18757127 DOI: 10.1016/j.envpol.2008.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 07/02/2008] [Accepted: 07/17/2008] [Indexed: 05/26/2023]
Abstract
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.
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Affiliation(s)
- Sari J Himanen
- University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio, Finland.
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13
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Wolfenbarger LL, Naranjo SE, Lundgren JG, Bitzer RJ, Watrud LS. Bt crop effects on functional guilds of non-target arthropods: a meta-analysis. PLoS One 2008; 3:e2118. [PMID: 18461164 PMCID: PMC2346550 DOI: 10.1371/journal.pone.0002118] [Citation(s) in RCA: 244] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Accepted: 03/10/2008] [Indexed: 11/18/2022] Open
Abstract
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 provide researchers with information to design more robust experiments and will inform the decisions of diverse stakeholders regarding the safety of transgenic insecticidal crops.
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Affiliation(s)
- L. LaReesa Wolfenbarger
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska, United States of America
| | - Steven E. Naranjo
- USDA-ARS Arid Land Agricultural Research Center, Maricopa, Arizona, United States of America
- * E-mail:
| | - Jonathan G. Lundgren
- USDA-ARS North Central Agricultural Research Laboratory, Brookings, South Dakota, United States of America
| | - Royce J. Bitzer
- Department of Entomology, Iowa State University, Iowa, United States of America
| | - Lidia S. Watrud
- U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, Oregon, United States of America
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14
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Himanen SJ, Nissinen A, Auriola S, Poppy GM, Stewart CN, Holopainen JK, Nerg AM. Constitutive and herbivore-inducible glucosinolate concentrations in oilseed rape (Brassica napus) leaves are not affected by Bt Cry1Ac insertion but change under elevated atmospheric CO2 and O3. PLANTA 2008; 227:427-437. [PMID: 17922289 DOI: 10.1007/s00425-007-0629-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 09/10/2007] [Accepted: 09/11/2007] [Indexed: 05/25/2023]
Abstract
Glucosinolates are plant secondary compounds involved in direct chemical defence by cruciferous plants against herbivores. The glucosinolate profile can be affected by abiotic and biotic environmental stimuli. We studied changes in glucosinolate patterns in leaves of non-transgenic oilseed rape (Brassica napus ssp. oleifera) under elevated atmospheric CO2 or ozone (O3) concentrations and compared them with those from transgenic for herbivore-resistance (Bacillus thuringiensis Cry1Ac endotoxin), to assess herbivory dynamics. Both elevated CO2 and O3 levels decreased indolic glucosinolate concentrations in transgenic and non-transgenic lines, whereas O3 specifically increased the concentration of an aromatic glucosinolate, 2-phenylethylglucosinolate. The herbivore-inducible indolic glucosinolate response was reduced in elevated O3 whereas elevated CO2 altered the induction dynamics of indolic and aliphatic glucosinolates. Herbivore-resistant Bt plants experienced minimal leaf damage after target herbivore Plutella xylostella feeding, but exhibited comparatively similar increase in glucosinolate concentrations after herbivory as non-transgenic plants, indicating that the endogenous glucosinolate defence was not severely compromised by transgenic modifications. The observed differences in constitutive and inducible glucosinolate concentrations of oilseed rape under elevated atmospheric CO2 and O3 might have implications for plant-herbivore interactions in Brassica crop-ecosystems in future climate scenarios.
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Affiliation(s)
- Sari J Himanen
- Department of Environmental Science, University of Kuopio, P.O. Box 1627, 70211, Kuopio, Finland.
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15
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Ibrahim MA, Stewart-Jones A, Pulkkinen J, Poppy GM, Holopainen JK. The influence of different nutrient levels on insect-induced plant volatiles in Bt and conventional oilseed rape plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2008; 10:97-107. [PMID: 18211550 DOI: 10.1111/j.1438-8677.2007.00013.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Transgenic Bt (expressing the cry1Ac endotoxin gene) and conventional oilseed rape plants grown in different soils were used to study nutrient uptake and emission of volatiles after herbivore damage. All plants were greenhouse-grown in soils representing low-, medium- and high-nutrient levels. The concentrations of N, P, K, Mg and Zn were significantly affected by the transgene, while the main effect of soil type appeared in N, P, Ca, Mg, B, Mn and Zn concentrations in the plants. Plants with four to five leaves were infested with the third instar larvae of Bt-susceptible Plutella xylostella for 48 h, and samples of volatiles were collected and analysed. In the first experiment, the soil nutrient level had a significant effect on the emissions of (Z)-3-hexen-1-ol, (Z)-3-hexenyl acetate, hexyl acetate, (E)-4,8-dimethyl-1,3,7-non-atriene (DMNT), beta-elemene, gamma-bisabolene, alpha-bisabolene and (E)-nerolidol. The induction of these volatiles was significantly higher in infested conventional plants grown at a high-soil nutrient level compared to infested conventional plants at a low-soil nutrient level. In the second experiment, the soil nutrient level had a significant effect on the emissions of (Z)-3-hexen-1-ol, (Z)-3-hexenyl acetate and beta-elemene and, again, this was significantly higher in infested conventional plants grown at high-soil nutrient levels in comparison with infested plants at a low-soil nutrient level. In both experiments, the transgene effect was significant on the emissions of DMNT and (E,E)-alpha-farnesene. The differences in emissions between the two separate experiments suggest that growth conditions (particularly daylength) and sampling procedure may affect the ratio of compounds detected in the emission blend, even though the response to herbivory, nutrient availability and the transgene were similar.
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Affiliation(s)
- M A Ibrahim
- Department of Environmental Science, University of Kuopio, Kuopio, Finland.
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16
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Rose R, Dively GP. Effects of insecticide-treated and Lepidopteran-active Bt transgenic sweet corn on the abundance and diversity of arthropods. ENVIRONMENTAL ENTOMOLOGY 2007; 36:1254-1268. [PMID: 18284751 DOI: 10.1603/0046-225x(2007)36[1254:eoialb]2.0.co;2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A field study was conducted over 2 yr to determine the effects of transgenic sweet corn containing a gene from the bacterium Bacillus thuringiensis (Bt) on the diversity and abundance of nontarget arthropods. The Bt hybrid (expressing Cry1Ab endotoxin for lepidopteran control) was compared with near-isogenic non-Bt and Bt hybrids treated with a foliar insecticide and with a near-isogenic non-Bt hybrid without insecticides. Plant inspections, sticky cards, and pitfall traps were used to sample a total of 573,672 arthropods, representing 128 taxonomic groups in 95 families and 18 orders. Overall biodiversity and community-level responses were not significantly affected by the transgenic hybrid. The Bt hybrid also had no significant adverse effects on population densities of specific nontarget herbivores, decomposers, and natural enemies enumerated at the family level during the crop cycle. As expected, the insecticide lambda-cyhalothrin had broad negative impacts on the abundance of many nontarget arthropods. One insecticide application in the Bt plots reduced the overall abundance of the natural enemy community by 21-48%. Five applications in the non-Bt plots reduced natural enemy communities by 33-70%. Nontarget communities affected in the insecticide-treated Bt plots exhibited some recovery, but communities exposed to five applications showed no trends toward recovery during the crop cycle. This study clearly showed that the nontarget effects of Bt transgenic sweet corn on natural enemies and other arthropods were minimal and far less than the community-level disruptions caused by lambda-cyhalothrin.
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Affiliation(s)
- Robyn Rose
- Biotechnology Regulatory Services, USDA, Animal and Plant Health Inspection Service, Unit 147, 4700 River Rd., Riverdale, MD 20737, USA
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17
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Sisterson MS, Carrière Y, Dennehy TJ, Tabashnik BE. Nontarget effects of transgenic insecticidal crops: implications of source-sink population dynamics. ENVIRONMENTAL ENTOMOLOGY 2007; 36:121-7. [PMID: 17349125 DOI: 10.1603/0046-225x(2007)36[121:neotic]2.0.co;2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Widespread planting of transgenic insecticidal (TI) crops for pest control has raised concerns about potential harm to nontarget arthropods. Because the first generation of TI crops produce single Bacillus thuringiensis (Bt) toxins causing little or no harm to most nontarget arthropods, they are not likely to cause such negative effects. However, varieties of transgenic crops with multiple Bt toxins or novel toxins might be more harmful to nontarget arthropods. Field studies assessing nontarget effects typically compare the relative abundance of nontarget arthropods in TI crop fields to non-TI crop fields. However, for nontarget arthropods that are killed by TI crops, such analyses may miss important effects. Results from simulations of a spatially explicit population dynamics model show that large-scale planting of TI crops could cause three types of negative effects on nontarget arthropods that suffer mortality caused by TI crops: (1) lower abundance in TI fields than non-TI fields with little or no effect on abundance in non-TI fields, (2) lower abundance in TI fields than non-TI fields and decreased abundance in non-TI fields, and (3) loss of the arthropod from TI and non-TI fields. Simulation results show that factors increasing the potential for negative effects of TI crops on nontarget arthropods in non-TI fields are low reproduction, high emigration, high adoption of TI crops, high mortality in TI fields, insecticide sprays, and rotation of TI and non-TI fields. The results suggest that risk assessment should consider the regional distribution of transgenic crops and the life history traits of nontarget arthropods to identify the most vulnerable regions and nontarget species.
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Affiliation(s)
- Mark S Sisterson
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
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18
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Dean JM, De Moraes CM. Effects of Genetic Modification on Herbivore-Induced Volatiles from Maize. J Chem Ecol 2006; 32:713-24. [PMID: 16718567 DOI: 10.1007/s10886-006-9040-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 12/06/2005] [Accepted: 12/30/2005] [Indexed: 10/24/2022]
Abstract
Large-scale implementation of transgenic crop varieties raises concerns about possible nontarget effects on other organisms. This study examines the effects of genetic modification on plant volatile production and its potential impact on arthropod population dynamics. We compared herbivore-induced volatile emissions from Bacillus thuringiensis Berliner (Bt) maize plants to those from a nontransformed isoline following exposure to various types of leaf damage. When equal numbers of Helicoverpa zea Boddie (Lepidoptera: Noctuidae) larvae fed on Bt and non-Bt maize, volatile emissions were significantly lower in the transgenic plants, which also exhibited less leaf damage. When damage levels were controlled by adding more larvae to Bt plants, the plants' volatile emissions increased but displayed significant differences from those of nontransgenic plants. Significantly higher amounts of linalool, beta-myrcene, and geranyl acetate were released from transgenic maize than from non-Bt plants. Manipulating the duration of feeding by individual larvae to produce similar damage patterns resulted in similar volatile profiles for Bt and non-Bt plants. Controlling damage levels more precisely by mechanically wounding leaves and applying larval regurgitant likewise resulted in similar emission patterns for Bt and non-Bt maize. Overall, changes in the herbivore-induced volatile profiles of Bt maize appeared to be a consequence of altered larval feeding behavior rather than of changes in biochemical plant defense pathways. The implications of these findings for understanding the impacts of plant-mediated cues on pest and natural enemy behavior in transgenic crop systems are discussed.
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Affiliation(s)
- Jennifer M Dean
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
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19
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Bruhn C, Earl R. Position of the American Dietetic Association: Agricultural and Food Biotechnology. ACTA ACUST UNITED AC 2006; 106:285-93. [PMID: 16442880 DOI: 10.1016/j.jada.2005.12.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Indexed: 11/23/2022]
Abstract
It is the position of the American Dietetic Association that agricultural and food biotechnology techniques can enhance the quality, safety, nutritional value, and variety of food available for human consumption and increase the efficiency of food production, food processing, food distribution, and environmental and waste management. The American Dietetic Association encourages the government, food manufacturers, food commodity groups, and qualified food and nutrition professionals to work together to inform consumers about this new technology and encourage the availability of these products in the marketplace.
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20
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Vojtech E, Meissle M, Poppy GM. Effects of Bt maize on the herbivore Spodoptera littoralis (Lepidoptera: Noctuidae) and the parasitoid Cotesia marginiventris (Hymenoptera: Braconidae). Transgenic Res 2005; 14:133-44. [PMID: 16022385 DOI: 10.1007/s11248-005-2736-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent studies have shown that transgenic insect resistant plants can have negative effects on non-target herbivores as well as on beneficial insects. The study of tritrophic interactions gives insight into the complex mechanisms of food webs in the field and can easily be incorporated into a tiered risk assessment framework. We investigated the effects of transgenic maize (Zea mays) expressing insecticidal proteins derived from Bacillus thuringiensis (Bt maize) on Spodoptera littoralis, a non-target herbivore, and on the hymenopteran parasitoid Cotesia marginiventris. In a laboratory study, S. littoralis larvae were reared for their whole lifespan on a mixture of leaves and stems from 2-4-week old Bt maize plants. S. littoralis survival, developmental times and larval weights were significantly affected by Bt maize diet. However, adult moths, which survived development on Bt maize, were the same size as the adults from the control group. C. marginiventris survival, developmental times and cocoon weights were significantly negatively affected if their S. littoralis host larva had been fed Bt maize. ELISA tests confirmed that S. littoralis larvae ingest high amounts of CrylA(b) toxin while feeding on Bt maize. In S. littoralis pupae and in C. marginiventris cocoon silk, only traces of the toxin could be detected. No toxin was found in S. littoralis and C. marginiventris adults. Thus the toxin is not accumulating in the trophic levels and in fact appears to be excreted. Our results suggest that the effects on C. marginiventris when developing in susceptible S. littoralis larvae are indirect (host mediated). The biological relevance of those results and the significance of this study in risk assessment are discussed.
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Affiliation(s)
- Eva Vojtech
- School of Biological Sciences, University of Southampton, Basset Crescent East, Southampton SO16 7PX, UK
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21
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Meissle M, Vojtech E, Poppy GM. Effects of Bt maize-fed prey on the generalist predator Poecilus cupreus L. (Coleoptera: Carabidae). Transgenic Res 2005; 14:123-32. [PMID: 16022384 DOI: 10.1007/s11248-004-6458-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the effects of transgenic maize (Zea mays) expressing Bacillus thuringienses toxin (Bt maize) on larval and adult Poecilus cupreus carabid beetles in laboratory studies. In no-choice trials, neonate P. cupreus larvae were fed exclusively with Spodoptera littoralis caterpillars, which had been raised on Bt maize. S. littoralis raised on conventional maize or "high quality" Calliphora sp. pupae were fed to the beetle larvae in two control treatments. Bt-maize-fed caterpillar prey increased mortality to 100% within 40 days. The experiment was repeated with 10-day-old beetle larvae. Bt treatment resulted in fewer pupae than in both controls, and in a higher mortality than in the Calliphora control. S. littoralis was suitable as exclusive prey in no-choice tests, at least for 40 days, although prey quality seemed to be low compared to Calliphora pupae. The observed effects are most likely indirect effects due to further reduced nutritional prey quality. However, direct effects cannot be excluded. In the second part of the study, exposure of P. cupreus to Bt intoxicated prey was examined in paired-choice tests. Adult beetles were offered a choice between different prey conditions (frozen and thawed, freshly killed or living), prey types (S. littoralis caterpillars, Calliphora sp. pupae, cereal aphids) and prey treatments (raised on Bt or conventional maize). Living prey was preferred to frozen and dead prey. Caterpillars were only preferred to fly pupae and aphids when living. Prey treatment seemed to be least important for prey selection. The tests showed that P. cupreus ingested caterpillars readily and there was no evidence of them avoiding Bt containing prey, which means exposure in the field could occur. The presented protocols are a first step towards ecological risk assessment for carabid beetles.
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Affiliation(s)
- Michael Meissle
- University of Southampton, School of Biological Sciences, Basset Crescent East, Southampton SO16 7PX, UK
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22
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Hubert J, Dolecková-Maresová L, Hýblová J, Kudlíková I, Stejskal V, Mares M. In vitro and in vivo inhibition of alpha-amylases of stored-product mite Acarus siro. EXPERIMENTAL & APPLIED ACAROLOGY 2005; 35:281-91. [PMID: 15969461 DOI: 10.1007/s10493-004-7834-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The stored-product mites are the most abundant and frequent group of pests living on the stored food products in Europe. They endanger public health since they produce allergens and transmit mycotoxin-producing fungi. Novel acaricidal compounds with inhibitory effects on the digestive enzymes of arthropods are a safe alternative to the traditional neurotoxic pesticides used for control of the stored-product pests. In this work, we explored the properties of acarbose, the low molecular weight inhibitor of alpha-amylases (AI), as a novel acaricide candidate for protection of the stored products from infestation by Acarus siro (Acari: Acaridae). In vitro analysis revealed that AI blocked efficiently the enzymatic activity of digestive amylases of A. siro, and decreased the physiological capacity of mite's gut in utilizing a starch component of grain flour. In vivo experiments showed that AI suppressed the population growth of A. siro. The mites were kept for three weeks on experimental diet enriched by AI in concentration range of 0.005 to 0.25%. Population growth of A. siro was negatively correlated with the content of AI in the treated diet with a half-population dose of 0.125%. The suppressive effect of AIs on stored-product mites is discussed in the context of their potential application in GMO crops.
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Affiliation(s)
- Jan Hubert
- Research Institute of Crop Production, Drnovska 506, 16106 Praha, Czech Republic
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23
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Pilson D, Prendeville HR. Ecological Effects of Transgenic Crops and the Escape of Transgenes into Wild Populations. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2004. [DOI: 10.1146/annurev.ecolsys.34.011802.132406] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
▪ Abstract Ecological risks associated with the release of transgenic crops include nontarget effects of the crop and the escape of transgenes into wild populations. Nontarget effects can be of two sorts: (a) unintended negative effects on species that do not reduce yield and (b) greater persistence of the crop in feral populations. Conventional agricultural methods, such as herbicide and pesticide application, have large and well-documented nontarget effects. To the extent that transgenes have more specific target effects, transgenic crops may have fewer nontarget effects. The escape of transgenes into wild populations, via hybridization and introgression, could lead to increased weediness or to the invasion of new habitats by the wild population. In addition, native species with which the wild plant interacts (including herbivores, pathogens, and other plant species in the community) could be negatively affected by “transgenic-wild” plants. Conventional crop alleles have facilitated the evolution of increased weediness in several wild populations. Thus, some transgenes that allow plants to tolerate biotic and abiotic stress (e.g., insect resistance, drought tolerance) could have similar effects.
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Affiliation(s)
- Diana Pilson
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0118;,
| | - Holly R. Prendeville
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0118;,
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Abstract
Assessing the risks associated with geneflow from GM crops to wild relatives is a significant scientific challenge. Most researchers have focused on assessing the frequency of gene flow, too often on a localized scale, and ignoring the hazards caused by geneflow. To quantify risk, multi-disciplinary research teams need to unite and scale up their studies.
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Affiliation(s)
- Guy M Poppy
- Ecology and Evolution Group, School of Biological Sciences, University of Southampton, Southampton, Hants, SO16 7PX, UK.
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25
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Bouchard E, Michaud D, Cloutier C. Molecular interactions between an insect predator and its herbivore prey on transgenic potato expressing a cysteine proteinase inhibitor from rice. Mol Ecol 2003; 12:2429-37. [PMID: 12919480 DOI: 10.1046/j.1365-294x.2003.01918.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transgenic plants expressing resistance to herbivorous insects may represent a safe and sustainable pest control alternative if they do not interfere with the natural enemies of target pests. Here we examined interactions between oryzacystatin I (OCI), a proteinase inhibitor from rice genetically engineered into potato (Solanum tuberosum cv. Kennebec, line K52) to increase resistance to insect herbivory, and the insect predator Perillus bioculatus. This stinkbug is a relatively specialized predator of caterpillars and leaf-beetle larvae, and may also include plant sap in its predominantly carnivorous diet. One of its preferred prey is Colorado potato beetle (Leptinotarsa decemlineata), a major target of insect resistance development for potato field crops. Gelatin/sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that a major fraction of proteinase (gelatinase) activity in P. bioculatus extracts is OCI-sensitive. Among five gelatinolytic bands detected, the slowest-moving one (proteinase I) was inhibited strongly by purified OCI expressed in Escherichia coli or by OCI-transgenic potato extracts, while three other proteinases were partly sensitive to these treatments. There was also evidence of slight inhibition of proteinase I by untransformed potato foliage, suggesting the presence of a natural inhibitor related to OCI at low level in potato foliage. Interestingly, only about 50% of the maximum potential activity of proteinase I was recovered in extracts of P. bioculatus feeding on L. decemlineata larval prey on a diet of OCI-potato foliage, indicating that the predator was sensitive to OCI in the midgut of its prey. However, P. bioculatus on OCI-prey survived, grew and developed normally, indicating ability to compensate prey-mediated exposure to the OCI inhibitor. Confinement of P. bioculatus to potato foliage provided no evidence that potato plant-derived nutrition is a viable alternative to predation, restriction to potato foliage in fact being inferior to free water for short-term survival of nonfeeding first-instar larvae. These results support the view that OCI, an effective inhibitor of a substantial fraction of digestive enzymatic potential in P. bioculatus, should not interfere with its predation potential when expressed in potato plants fed to its prey at a maximum level of approximately 0.8% of total soluble proteins in mature foliage.
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Affiliation(s)
- Edith Bouchard
- Département de Biologie, Centre de recherche en horticulture, Université Laval, Cité Universitaire (Québec), Canada G1K 7P4
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Bouchard E, Cloutier C, Michaud D. Oryzacystatin I expressed in transgenic potato induces digestive compensation in an insect natural predator via its herbivorous prey feeding on the plant. Mol Ecol 2003; 12:2439-46. [PMID: 12919481 DOI: 10.1046/j.1365-294x.2003.01919.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We observed recently that the rice cysteine proteinase inhibitor, oryzacystatin I (OCI) expressed in transgenic potato does not affect growth and development of the two-spotted stinkbug predator (Perillus bioculatus) via its herbivorous prey feeding on the plant. Here we monitored the inhibitory activity of recombinant OCI along this potato --> herbivore --> predator continuum, to determine if the absence of effect was associated with a digestive compensatory response of the predator following inhibition of its proteinases by the recombinant cystatin. After confirming that OCI is present in the plant, and ingested in an active form by potato beetle larvae, quantitative and electrophoretic assays allowed us to determine that the recombinant cystatin (representing about 0.8% of total soluble proteins in leaves) was entirely bound to a approximately 30-kDa target proteinase in the prey's midgut, forming a sodium dodecyl sulphate (SDS)-stable complex detected on immunoblots with an anti-OCI polyclonal antibody. Despite the apparent absence of free, residual OCI in the beetle's midgut, digestive protease activity in the predator, known to include OCI-sensitive activity, was altered negatively when the prey was fed the modified plant. This inhibitory process at the third trophic level was accompanied by a compensatory response in the predator, by which serine-type proteinases were synthesized de novo. Overall, our data suggest that the affinity between OCI and the predator's OCI-sensitive proteinases is: (i) as strong as (or stronger than) the affinity between OCI and the potato beetle 30-kDa-sensitive proteinase; and (ii) stronger than the affinity between these enzymes and the plant endogenous homologue of OCI, potato multicystatin, induced in the plant by potato beetle feeding. Our results also show that predatory organisms can adapt their digestive metabolism to the presence of plant antidigestive proteins ingested by their herbivorous preys. In a broader context, this study stresses the need to monitor the inhibitory effects of PI-expressing plants not only on the herbivorous insects targeted, but also on the organisms likely to consume these pests in the environment.
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Affiliation(s)
- Edith Bouchard
- Département de Biologie, Centre de recherche en horticulture, Université Laval, Cité Universitaire (Québec), Canada G1K 7P4
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Wilkinson MJ, Sweet J, Poppy GM. Risk assessment of GM plants: avoiding gridlock? TRENDS IN PLANT SCIENCE 2003; 8:208-12. [PMID: 12758037 DOI: 10.1016/s1360-1385(03)00057-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cultivation of genetically modified crops is presently based largely on four crops containing few transgenes and grown in four countries. This will soon change and pose new challenges for risk assessment. A more structured approach that is as generic as possible is advocated to study consequences of gene flow. Hazards should be precisely defined and prioritized, with emphasis on quantifying elements of exposure. This requires coordinated effort between large, multidisciplinary research teams.
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Affiliation(s)
- Mike J Wilkinson
- School of Plant Sciences, The University of Reading, Whiteknights, Reading, UK RG6 6AS.
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Down RE, Ford L, Woodhouse SD, Davison GM, Majerus MEN, Gatehouse JA, Gatehouse AMR. Tritrophic interactions between transgenic potato expressing snowdrop lectin (GNA), an aphid pest (peach-potato aphid; Myzus persicae (Sulz.) and a beneficial predator (2-spot ladybird; Adalia bipunctata L.). Transgenic Res 2003; 12:229-41. [PMID: 12739890 DOI: 10.1023/a:1022904805028] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Tritrophic interactions between transgenic potato expressing the insecticidal lectin from snowdrop (Galanthus nivalis agglutinin; GNA), an aphid pest, Myzus persicae (Sulz.), and a beneficial predator, the 2-spot ladybird (Adalia bipunctata L.) were investigated. Clonal plants expressing GNA at 0.1-0.2% total soluble protein in leaves were used. No significant effects on development and survival of ladybird larvae fed on aphids from these transgenic plants were observed, with larval survival in the experimental group being 90% compared to 89% for controls. There were also no effects on subsequent female or male longevity. Female fecundity was also investigated. Although no significant differences (p > 0.05) were observed in egg production between control and experimental groups, a 10%, reduction (p < 0.01) in egg viability (determined by % hatch) occurred in ladybirds fed aphids reared on transgenic plants. Additional studies were carried out using aphids fed on artificial diet containing GNA, to deliver quantified levels of the protein to ladybird adults. GNA had no deleterious effects upon adult longevity, but resulted in a consistent trend for improved fecundity. Egg production was increased by up to 70% and egg viability also increased significantly. The results suggest that GNA is not deleterious to ladybirds. Results from these studies highlight the need to discriminate between direct and indirect effects when studying tritrophic interactions between plants/pests/natural enemies. Furthermore, it emphasises the importance of demonstrating 'cause and effect'.
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Affiliation(s)
- Rachel E Down
- School of Biology, King George VI Building, University of Newcastle, NE1 7RU, Newcastle upon Tyne, UK
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Perry JN, Rothery P, Clark SJ, Heard MS, Hawes C. Design, analysis and statistical power of the Farm-Scale Evaluations of genetically modified herbicide-tolerant crops. J Appl Ecol 2003. [DOI: 10.1046/j.1365-2664.2003.00786.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Bourguet D, Chaufaux J, Micoud A, Delos M, Naibo B, Bombarde F, Marque G, Eychenne N, Pagliari C. Ostrinia nubilalisparasitism and the field abundance of non-target insects in transgenicBacillus thuringiensiscorn (Zea mays). ACTA ACUST UNITED AC 2002; 1:49-60. [PMID: 15612256 DOI: 10.1051/ebr:2002005] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In this study, we evaluated in field trials the effects on non-target species, of transgenic corn producing the Cry1Ab toxin of Bacillus thuringiensis (Bt). In 1998, we collected Ostrinia nubilalis (Hübner) larvae from transgenic Bt corn (Novartis Hybrid 176) and non-Bt corn at four geographical sites. We found a significant variation in parasitism by the tachinids Lydella thompsoni (Herting) and Pseudoperichaeta nigrolineata (Walker) among sites, and more parasitism in non-Bt than in Bt fields. The Bt effect did not vary significantly among fields. In 1999, we performed a field experiment at two sites, comparing the temporal abundance of non-target arthropods in Bt corn (Monsanto Hybrid MON810) and non-Bt corn. The non-target insects studied included the aphids Metopolophium dirhodum (Walker), Rhopalosiphum padi (L.) and Sitobion avenae (F.), the bug Orius insidiosus (Say), the syrphid Syrphus corollae (Meigen), the ladybird Coccinella septempunctata (L.), the lacewing Chrysoperla carnea (Stephens), thrips and hymenopteran parasitoids. For all species but one, the number of individuals varied greatly over the season but did not differ between the types of corn. The only exception was thrips which, at one site, was significantly more abundant in Bt corn than in non-Bt corn. However this difference did not remain significant when we took the multiple tests into account. Implications for pest resistance management, population dynamics and risk assessment are discussed.
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Affiliation(s)
- Denis Bourguet
- Unité de Recherches de Lutte Biologique, INRA La Minière, 78285 Guyancourt, France.
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Groot AT, Dicke M. Insect-resistant transgenic plants in a multi-trophic context. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 31:387-406. [PMID: 12182699 DOI: 10.1046/j.1365-313x.2002.01366.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
So far, genetic engineering of plants in the context of insect pest control has involved insertion of genes that code for toxins, and may be characterized as the incorporation of biopesticides into classical plant breeding. In the context of pesticide usage in pest control, natural enemies of herbivores have received increasing attention, because carnivorous arthropods are an important component of insect pest control. However, in plant breeding programmes, natural enemies of herbivores have largely been ignored, although there are many examples that show that plant breeding affects the effectiveness of biological control. Negative influences of modified plant characteristics on carnivorous arthropods may induce population growth of new, even more harmful pest species that had no pest status prior to the pesticide treatment. Sustainable pest management will only be possible when negative effects on non-target, beneficial arthropods are minimized. In this review, we summarize the effects of insect-resistant crops and insect-resistant transgenic crops, especially Bt crops, from a food web perspective. As food web components, we distinguish target herbivores, non-target herbivores, pollinators, parasitoids and predators. Below-ground organisms such as Collembola, nematodes and earthworms should also be included in risk assessment studies, but have received little attention. The toxins produced in Bt plants retain their toxicity when bound to the soil, so accumulation of these toxins is likely to occur. Earthworms ingest the bound toxins but are not affected by them. However, earthworms may function as intermediaries through which the toxins are passed on to other trophic levels. In studies where effects of insect-resistant (Bt) plants on natural enemies were considered, positive, negative and no effects have been found. So far, most studies have concentrated on natural enemies of target herbivores. However, Bt toxins are structurally rearranged when they bind to midgut receptors, so that they are likely to lose their toxicity inside target herbivores. What happens to the toxins in non-target herbivores, and whether these herbivores may act as intermediaries through which the toxins may be passed on to the natural enemies, remains to be studied.
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Affiliation(s)
- Astrid T Groot
- Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH Wageningen, The Netherlands
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Couty A, Down RE, Gatehouse AM, Kaiser L, Pham-Delègue MH, Poppy GM. Effects of artificial diet containing GNA and GNA-expressing potatoes on the development of the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Aphidiidae). JOURNAL OF INSECT PHYSIOLOGY 2001; 47:1357-1366. [PMID: 12770142 DOI: 10.1016/s0022-1910(01)00111-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Aphid parasitoids are important biological control agents. The possibility arises that whilst foraging on insect-resistant transgenic plants, they are themselves at risk from direct and indirect effects of the expression of a transgene used to control the pest species. A liquid artificial diet was successfully used to deliver the snowdrop lectin (Galanthus nivalis agglutinin; GNA) to the peach-potato aphid, Myzus persicae. Bioassays utilising artificial diet incorporating GNA, and excised leaves of the GNA-expressing transgenic potato line, GNA2#28, were performed to assess the potential effects of GNA on the development of the aphid parasitoid Aphidius ervi. The results indicate that GNA delivered via artificial diet to the aphids can be transferred through the trophic levels and has a dose-dependent effect on parasitoid development. Parasitoid larvae excreted most of the ingested GNA in the meconium but some of it was detected in the pupae. Although A. ervi development was not affected when developing within hosts feeding on transgenic potato leaves, this probably reflected sub-optimal expression of the toxin in the transgenic potato line used
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Affiliation(s)
- A Couty
- Department of Entomology and Nematology, IACR-Rothamsted, AL5 2JQ, Harpenden, UK
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Stanley-Horn DE, Dively GP, Hellmich RL, Mattila HR, Sears MK, Rose R, Jesse LC, Losey JE, Obrycki JJ, Lewis L. Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies. Proc Natl Acad Sci U S A 2001; 98:11931-6. [PMID: 11559839 PMCID: PMC59745 DOI: 10.1073/pnas.211277798] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Survival and growth of monarch larvae, Danaus plexippus (L.), after exposure to either Cry1Ab-expressing pollen from three Bacillus thuringiensis (Bt) corn (Zea mays L.) events differing in toxin expression or to the insecticide, lambda-cyhalothrin, were examined in field studies. First instars exposed to low doses ( approximately 22 grains per cm(2)) of event-176 pollen gained 18% less weight than those exposed to Bt11 or Mon810 pollen after a 5-day exposure period. Larvae exposed to 67 pollen grains per cm(2) on milkweed leaves from within an event-176 field exhibited 60% lower survivorship and 42% less weight gain compared with those exposed to leaves from outside the field. In contrast, Bt11 pollen had no effect on growth to adulthood or survival of first or third instars exposed for 5 days to approximately 55 and 97 pollen grains per cm(2), respectively. Similarly, no differences in larval survivorship were observed after a 4-day exposure period to leaves with 504-586 (within fields) or 18-22 (outside the field) pollen grains per cm(2) collected from Bt11 and non-Bt sweet-corn fields. However, survivorship and weight gain were drastically reduced in non-Bt fields treated with lambda-cyhalothrin. The effects of Bt11 and Mon810 pollen on the survivorship of larvae feeding 14 to 22 days on milkweeds in fields were negligible. Further studies should examine the lifetime and reproductive impact of Bt11 and Mon810 pollen on monarchs after long-term exposure to naturally deposited pollen.
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Affiliation(s)
- D E Stanley-Horn
- Department of Environmental Biology, University of Guelph, Guelph, ON, Canada.
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Abstract
Plant diseases are a major threat to the world food supply, as up to 15% of production is lost to pathogens. In the past, disease control and the generation of resistant plant lines protected against viral, bacterial or fungal pathogens, was achieved using conventional breeding based on crossings, mutant screenings and backcrossing. Many approaches in this field have failed or the resistance obtained has been rapidly broken by the pathogens. Recent advances in molecular biotechnology have made it possible to obtain and to modify genes that are useful for generating disease resistant crops. Several strategies, including expression of pathogen-derived sequences or anti-pathogenic agents, have been developed to engineer improved pathogen resistance in transgenic plants. Antibody-based resistance is a novel strategy for generating transgenic plants resistant to pathogens. Decades ago it was shown that polyclonal and monoclonal antibodies can neutralize viruses, bacteria and selected fungi. This approach has been improved recently by the development of recombinant antibodies (rAbs). Crop resistance can be engineered by the expression of pathogen-specific antibodies, antibody fragments or antibody fusion proteins. The advantages of this approach are that rAbs can be engineered against almost any target molecule, and it has been demonstrated that expression of functional pathogen-specific rAbs in plants confers effective pathogen protection. The efficacy of antibody-based resistance was first shown for plant viruses and its application to other plant pathogens is becoming more established. However, successful use of antibodies to generate plant pathogen resistance relies on appropriate target selection, careful antibody design, efficient antibody expression, stability and targeting to appropriate cellular compartments.
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Affiliation(s)
- S Schillberg
- FraunhoferAbteilung für Molekulare Biotechnologie, IUCT, Grafschaft, Schmallenberg, Germany.
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Couty A, de la Viña G, Clark SJ, Kaiser L, Pham-Delègue MH, Poppy GM. Direct and indirect sublethal effects of Galanthus nivalis agglutinin (GNA) on the development of a potato-aphid parasitoid, Aphelinus abdominalis (Hymenoptera: Aphelinidae). JOURNAL OF INSECT PHYSIOLOGY 2001; 47:553-561. [PMID: 11249943 DOI: 10.1016/s0022-1910(00)00148-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Snowdrop lectin (Galanthus nivalis agglutinin, GNA), has been shown to confer partial resistance to two potato aphids Myzus persicae and Aulacorthum solani, when incorporated in artificial diet and/or expressed in transgenic potato. First-tier laboratory-scale experiments were conducted to assess the potential effect of GNA on the aphid parasitoid Aphelinus abdominalis. GNA (0.1% w/v) was successfully delivered to Macrosiphum euphorbiae via artificial diet and induced a reduced growth rate and increased mortality compared to aphids fed a control diet. As aphid parasitoid larvae are endophagous, they may be exposed to GNA during their larval development and potential "chronic toxicity" on A. abdominalis was investigated. The amounts of GNA present in aphid and parasitoid tissues were estimated by western blotting. Results suggest that parasitoids excrete most of the GNA ingested. Sublethal effects of GNA on several parasitoid fitness parameters (parasitism success, parasitoid development and size, emergence success, progeny survival and sex ratio) were studied. No direct detrimental effect of GNA on A. abdominalis was observed. However, GNA had an indirect host-size-mediated effect on the sex ratio and the size of parasitoids developing in GNA-fed aphids. This work highlights the need to determine the exact "causes and effects" when assessing the ecological impact of transgenic plants on non-target beneficial insects. Such bioassays form the basis of a tiered risk assessment moving from laboratory studies assessing individuals towards field-scale experiments assessing populations.
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Affiliation(s)
- A Couty
- Department of Entomology/Nematology, IACR-Rothamsted, Herts AL5 2JQ, Harpenden, UK
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Raps A, Kehr J, Gugerli P, Moar WJ, Bigler F, Hilbeck A. Immunological analysis of phloem sap of Bacillus thuringiensis corn and of the nontarget herbivore Rhopalosiphum padi (Homoptera: Aphididae) for the presence of Cry1Ab. Mol Ecol 2001; 10:525-33. [PMID: 11298965 DOI: 10.1046/j.1365-294x.2001.01236.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Phloem sap of transgenic Bacillus thuringiensis (Bt) corn expressing a truncated form of the B. thuringiensis delta-endotoxin Cry1Ab, sap sucking aphids feeding on Bt corn and their honeydew were analysed for presence of Cry1Ab using ELISA. Phloem sap of Bt and non-Bt corn was collected using a newly developed technique with a microcapillary being directly inserted into the phloem tubes. Using this technique, no Cry1Ab was detected in the phloem sap. In contrast, measurable concentrations of Cry1Ab in the range of 1 ppb were detected when phloem sap of pooled leaf samples was extracted using EDTA buffer. This was probably because of Cry1Ab toxin released from damaged cells. When analysing apterous adults of Rhopalosiphum padi L. and their honeydew, no Cry1Ab could be detected. In contrast, Cry1Ab was clearly detected in both larvae of the leaf chewing herbivore Spodoptera littoralis (Boisduval) and their faeces, showing that Cry1Ab is detectable after ingestion and excretion by herbivores. These results suggest that R. padi ingests or contains no or only very low concentrations of Cry1Ab in the range of the detection limit. In consequence it is hypothesized that R. padi as an important prey for beneficial insects in corn is unlikely to cause any harm to its antagonists due to mediating Bt toxin.
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Affiliation(s)
- A Raps
- Swiss Federal Research Station of Agroecology and Agriculture, CH-8046 Zürich, Switzerland.
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