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Fabrick JA, Li X, Carrière Y, Tabashnik BE. Molecular Genetic Basis of Lab- and Field-Selected Bt Resistance in Pink Bollworm. INSECTS 2023; 14:insects14020201. [PMID: 36835770 PMCID: PMC9959750 DOI: 10.3390/insects14020201] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/03/2023] [Accepted: 02/14/2023] [Indexed: 05/17/2023]
Abstract
Transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) control some important insect pests. However, evolution of resistance by pests reduces the efficacy of Bt crops. Here we review resistance to Bt cotton in the pink bollworm, Pectinophora gossypiella, one of the world's most damaging pests of cotton. Field outcomes with Bt cotton and pink bollworm during the past quarter century differ markedly among the world's top three cotton-producing countries: practical resistance in India, sustained susceptibility in China, and eradication of this invasive lepidopteran pest from the United States achieved with Bt cotton and other tactics. We compared the molecular genetic basis of pink bollworm resistance between lab-selected strains from the U.S. and China and field-selected populations from India for two Bt proteins (Cry1Ac and Cry2Ab) produced in widely adopted Bt cotton. Both lab- and field-selected resistance are associated with mutations affecting the cadherin protein PgCad1 for Cry1Ac and the ATP-binding cassette transporter protein PgABCA2 for Cry2Ab. The results imply lab selection is useful for identifying genes important in field-evolved resistance to Bt crops, but not necessarily the specific mutations in those genes. The results also suggest that differences in management practices, rather than genetic constraints, caused the strikingly different outcomes among countries.
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Affiliation(s)
- Jeffrey A. Fabrick
- USDA ARS, U.S. Arid Land Agricultural Research Center, Maricopa, AZ 85138, USA
- Correspondence:
| | - Xianchun Li
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA
| | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA
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Impact of Caterpillar Increased Feeding Rates on Reduction of Bt Susceptibility. Int J Mol Sci 2022; 23:ijms232314856. [PMID: 36499184 PMCID: PMC9735560 DOI: 10.3390/ijms232314856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 12/05/2022] Open
Abstract
The use of insect-resistant transgenic crops producing Bacillus thuringiensis protein Cry toxins (Bt) to control caterpillars is wide-spread. Development of a mechanism to prevent Bt from reaching its target site in the digestive system could result in Bt resistance and resistance to other insecticides active per os. Increased feeding rates by increasing temperature in tobacco budworms, Chloridea virescens, and bollworms, Helicoverpa zea, decreased Bt Cry1Ac susceptibility and mortality. The same was found in C. virescens for Bollgard II plant extract containing Bt Cry1Ac and Cry2Ab2 toxins. Furthermore, H. zea from the same inbred laboratory colony that fed faster independent of temperature manipulation were less susceptible to Bt intoxication. A laboratory derived C. virescens Bt resistant strain demonstrated a higher feeding rate on non-Bt artificial diet than the parental, Bt susceptible strain. A laboratory-reared Bt resistant fall armyworm, Spodoptera frugiperda, strain also fed faster on non-Bt diet compared to Bt susceptible caterpillars of the same species, both originally collected from corn. The studies in toto and the literature reviewed support the hypothesis that increased feeding rate is a behavioral mechanism for reducing caterpillar susceptibility to Bt. Its possible role in resistance needs further study.
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Tabashnik BE, Unnithan GC, Yelich AJ, Fabrick JA, Dennehy TJ, Carrière Y. Responses to Bt toxin Vip3Aa by pink bollworm larvae resistant or susceptible to Cry toxins. PEST MANAGEMENT SCIENCE 2022; 78:3973-3979. [PMID: 35633103 DOI: 10.1002/ps.7016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/17/2022] [Accepted: 05/28/2022] [Indexed: 05/29/2023]
Abstract
BACKGROUND Transgenic crops that make insecticidal proteins from Bacillus thuringiensis (Bt) have revolutionized management of some pests. However, evolution of resistance to Bt toxins by pests diminishes the efficacy of Bt crops. Resistance to crystalline (Cry) Bt toxins has spurred adoption of crops genetically engineered to produce the Bt vegetative insecticidal protein Vip3Aa. Here we used laboratory diet bioassays to evaluate responses to Vip3Aa by pink bollworm (Pectinophora gossypiella), one of the world's most damaging pests of cotton. RESULTS Against pink bollworm larvae susceptible to Cry toxins, Vip3Aa was less potent than Cry1Ac or Cry2Ab. Conversely, Vip3Aa was more potent than Cry1Ac or Cry2Ab against laboratory strains highly resistant to those Cry toxins. Five Cry-susceptible field populations were less susceptible to Vip3Aa than a Cry-susceptible laboratory strain (APHIS-S). Relative to APHIS-S, significant resistance to Vip3Aa did not occur in strains selected in the laboratory for > 700-fold resistance to Cry1Ac or both Cry1Ac and Cry2Ab. CONCLUSIONS Resistance to Cry1Ac and Cry2Ab did not cause strong cross-resistance to Vip3Aa in pink bollworm, which is consistent with predictions based on the lack of shared midgut receptors between these toxins and previous results from other lepidopterans. Comparison of the Bt toxin concentration in plants relative to the median lethal concentration (LC50 ) from bioassays may be useful for estimating efficacy. The moderate potency of Vip3Aa against Cry1Ac- and Cry2Ab-resistant and susceptible pink bollworm larvae suggests that Bt cotton producing this toxin together with novel Cry toxins might be useful as one component of integrated pest management. © 2022 Society of Chemical Industry.
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Affiliation(s)
| | | | | | - Jeffrey A Fabrick
- USDA ARS, US Arid Land Agricultural Research Center, Maricopa, AZ, USA
| | | | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ, USA
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Van den Berg J, Greyvenstein B, du Plessis H. Insect resistance management facing African smallholder farmers under climate change. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100894. [PMID: 35247642 DOI: 10.1016/j.cois.2022.100894] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Changes in climatic conditions affect pest populations and ultimately result in increased pest status and yield losses. While pesticide application is usually the first defensive tool used to control pest species that threaten crop production, genetically modified (GM) crops with insecticidal traits (Bt crops) are becoming more common. The indiscriminate and over use of insecticides, and absence of insect resistance management (IRM) strategies ultimately lead to evolution of resistance against these technologies. IRM faces significant challenges in the African context. In this paper we use examples of cotton, maize, cowpea and tomato pests to illustrate their potential to evolve resistance to insecticides and also highlight the importance of IRM strategies, both with regard to the use of pesticides and the cultivation of Bt cotton, Bt maize and Bt cowpea.
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Affiliation(s)
- Johnnie Van den Berg
- IPM Program, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa.
| | - Bianca Greyvenstein
- IPM Program, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa
| | - Hannalene du Plessis
- IPM Program, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2520, South Africa
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Ye J, Guo J, Li T, Tian J, Yu M, Wang X, Majeed U, Song W, Xiao J, Luo Y, Yue T. Phage-based technologies for highly sensitive luminescent detection of foodborne pathogens and microbial toxins: A review. Compr Rev Food Sci Food Saf 2022; 21:1843-1867. [PMID: 35142431 DOI: 10.1111/1541-4337.12908] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 12/25/2021] [Accepted: 12/28/2021] [Indexed: 02/05/2023]
Abstract
Foodborne pathogens and microbial toxins are the main causes of foodborne illness. However, trace pathogens and toxins in foods are difficult to detect. Thus, techniques for their rapid and sensitive identification and quantification are urgently needed. Phages can specifically recognize and adhere to certain species of microbes or toxins due to molecular complementation between capsid proteins of phages and receptors on the host cell wall or toxins, and thus they have been successfully developed into a detection platform for pathogens and toxins. This review presents an update on phage-based luminescent detection technologies as well as their working principles and characteristics. Based on phage display techniques of temperate phages, reporter gene detection assays have been designed to sensitively detect trace pathogens by luminous intensity. By the host-specific lytic effects of virulent phages, enzyme-catalyzed chemiluminescent detection technologies for pathogens have been exploited. Notably, these phage-based luminescent detection technologies can discriminate viable versus dead microbes. Further, highly selective and sensitive immune-based assays have been developed to detect trace toxins qualitatively and quantitatively via antibody analogs displayed by phages, such as phage-ELISA (enzyme-linked immunosorbent assay) and phage-IPCR (immuno-polymerase chain reaction). This literature research may lead to novel and innocuous phage-based rapid detection technologies to ensure food safety.
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Affiliation(s)
- Jianming Ye
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Jiaqing Guo
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Tairan Li
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Jiaxin Tian
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Mengxi Yu
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Xiaochen Wang
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Usman Majeed
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Wei Song
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China
| | - Jianbo Xiao
- Department of Analytical Chemistry and Food Science, Faculty of Food Science and Technology, University of Vigo-Ourense Campus, Ourense, Spain
| | - Yane Luo
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China.,Laboratory of Nutritional and Healthy Food-Individuation Manufacturing Engineering, Xi'an, Shaanxi, China.,Research Center of Food Safety Risk Assessment and Control, Xi'an, Shaanxi, China
| | - Tianli Yue
- College of Food Science and Technology, Northwest University, Xi'an, Shaanxi, China.,Laboratory of Nutritional and Healthy Food-Individuation Manufacturing Engineering, Xi'an, Shaanxi, China.,Research Center of Food Safety Risk Assessment and Control, Xi'an, Shaanxi, China
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Lawrie RD, Mitchell RD, Deguenon JM, Ponnusamy L, Reisig D, Pozo-Valdivia AD, Kurtz RW, Roe RM. Characterization of Long Non-Coding RNAs in the Bollworm, Helicoverpa zea, and Their Possible Role in Cry1Ac-Resistance. INSECTS 2021; 13:12. [PMID: 35055855 PMCID: PMC8779162 DOI: 10.3390/insects13010012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 12/13/2022]
Abstract
Multiple insect pest species have developed field resistance to Bt-transgenic crops. There has been a significant amount of research on protein-coding genes that contribute to resistance, such as the up-regulation of protease activity or altered receptors. However, our understanding of the role of non-protein-coding mechanisms in Bt-resistance is minimal, as is also the case for resistance to chemical pesticides. To address this problem relative to Bt, RNA-seq was used to examine statistically significant, differential gene expression between a Cry1Ac-resistant (~100-fold resistant) and Cry1Ac-susceptible strain of Helicoverpa zea, a prevalent caterpillar pest in the USA. Significant differential expression of putative long non-coding RNAs (lncRNAs) was found in the Cry1Ac-resistant strain (58 up- and 24 down-regulated gene transcripts with an additional 10 found only in resistant and four only in susceptible caterpillars). These lncRNAs were examined as potential pseudogenes and for their genomic proximity to coding genes, both of which can be indicative of regulatory relationships between a lncRNA and coding gene expression. A possible pseudogenic lncRNA was found with similarities to a cadherin. In addition, putative lncRNAs were found significantly proximal to a serine protease, ABC transporter, and CYP coding genes, potentially involved in the mechanism of Bt and/or chemical insecticide resistance. Characterization of non-coding genetic mechanisms in Helicoverpa zea will improve the understanding of the genomic evolution of insect resistance, improve the identification of specific regulators of coding genes in general (some of which could be important in resistance), and is the first step for potentially targeting these regulators for pest control and resistance management (using molecular approaches, such as RNAi and others).
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Affiliation(s)
- Roger D. Lawrie
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7647, 3230 Ligon Street, Raleigh, NC 27695, USA; (R.D.L.); (R.D.M.III); (J.M.D.); (L.P.)
- Environmental and Molecular Toxicology Program, Department of Biology, College of Sciences, North Carolina State University, 2601 Stinson Drive, Raleigh, NC 27606, USA
| | - Robert D. Mitchell
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7647, 3230 Ligon Street, Raleigh, NC 27695, USA; (R.D.L.); (R.D.M.III); (J.M.D.); (L.P.)
- Office of Pesticide Programs, Invertebrate and Vertebrate Branch 1, Registration Division, U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue, Washington, DC 20460, USA
| | - Jean Marcel Deguenon
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7647, 3230 Ligon Street, Raleigh, NC 27695, USA; (R.D.L.); (R.D.M.III); (J.M.D.); (L.P.)
| | - Loganathan Ponnusamy
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7647, 3230 Ligon Street, Raleigh, NC 27695, USA; (R.D.L.); (R.D.M.III); (J.M.D.); (L.P.)
| | - Dominic Reisig
- Vernon G. James Research & Extension Center, Department of Entomology and Plant Pathology, 207 Research Station Road, Plymouth, NC 27962, USA; (D.R.); (A.D.P.-V.)
| | - Alejandro Del Pozo-Valdivia
- Vernon G. James Research & Extension Center, Department of Entomology and Plant Pathology, 207 Research Station Road, Plymouth, NC 27962, USA; (D.R.); (A.D.P.-V.)
| | - Ryan W. Kurtz
- Cotton Incorporated, 6399 Weston Parkway, Cary, NC 27513, USA;
| | - Richard Michael Roe
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7647, 3230 Ligon Street, Raleigh, NC 27695, USA; (R.D.L.); (R.D.M.III); (J.M.D.); (L.P.)
- Environmental and Molecular Toxicology Program, Department of Biology, College of Sciences, North Carolina State University, 2601 Stinson Drive, Raleigh, NC 27606, USA
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7
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Pereira AE, Huynh MP, Carlson AR, Haase A, Kennedy RM, Shelby KS, Coudron TA, Hibbard BE. Assessing the Single and Combined Toxicity of the Bioinsecticide Spear and Cry3Bb1 Protein Against Susceptible and Resistant Western Corn Rootworm Larvae (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2021; 114:2220-2228. [PMID: 34453170 DOI: 10.1093/jee/toab160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Indexed: 06/13/2023]
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), poses a serious threat to maize (Zea mays L.) growers in the U.S. Corn Belt. Transgenic corn expressing Bacillus thuringiensis (Bt) Berliner is the major management tactic along with crop rotation. Bt crops targeting WCR populations have been widely planted throughout the Corn Belt. Rootworms have developed resistance to nearly all management strategies including Bt corn. Therefore, there is a need for new products that are not cross-resistant with the current Bt proteins. In this study, we evaluated the susceptibility of WCR strains resistant and susceptible to Cry3Bb1 to the biological insecticide Spear-T (GS-omega/kappa-Hexatoxin-Hv1a) alone and combined with Cry3Bb1 protein. The activity of Hv1a alone was similar between Cry3Bb1-resistant and susceptible strains (LC50s = 0.95 mg/cm2 and 1.50 mg/cm2, respectively), suggesting that there is no cross-resistance with Cry3Bb1 protein. Effective concentration (EC50), molt inhibition concentration (MIC50), and inhibition concentration (IC50) values of Hv1a alone were also similar between both strains, based on non-overlapping confidence intervals. Increased mortality (64%) was observed on resistant larvae exposed to Hv1a (0.6 mg/cm2) + Cry3Bb1 protein (170.8 µg/cm2) compared to 0% mortality when exposed to Cry3Bb1 alone and 34% mortality to Hv1a alone (0.3 mg/cm2). The time of larval death was not significantly different between Hv1a alone (3.79 mg/cm2) and Hv1a (0.6 mg/cm2) + Cry3Bb1 (170.8 µg/cm2). New control strategies that are not cross-resistant with current insecticides and Bt proteins are needed to better manage the WCR, and Hv1a together with Cry3Bb1 may fit this role.
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Affiliation(s)
- Adriano E Pereira
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
| | - Man P Huynh
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
| | | | | | | | - Kent S Shelby
- Biological Control of Insect Research Laboratory, USDA/ARS, Columbia, MO, USA
| | - Thomas A Coudron
- Biological Control of Insect Research Laboratory, USDA/ARS, Columbia, MO, USA
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CRISPR-mediated mutations in the ABC transporter gene ABCA2 confer pink bollworm resistance to Bt toxin Cry2Ab. Sci Rep 2021; 11:10377. [PMID: 34001946 PMCID: PMC8128902 DOI: 10.1038/s41598-021-89771-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/28/2021] [Indexed: 11/29/2022] Open
Abstract
Crops genetically engineered to produce insecticidal proteins from Bacillus thuringiensis (Bt) have many benefits and are important globally for managing insect pests. However, the evolution of pest resistance to Bt crops reduces their benefits. Understanding the genetic basis of such resistance is needed to better monitor, manage, and counter pest resistance to Bt crops. Previous work shows that resistance to Bt toxin Cry2Ab is associated with mutations in the gene encoding the ATP-binding cassette protein ABCA2 in lab- and field-selected populations of the pink bollworm (Pectinophora gossypiella), one of the world’s most destructive pests of cotton. Here we used CRISPR/Cas9 gene editing to test the hypothesis that mutations in the pink bollworm gene encoding ABCA2 (PgABCA2) can cause resistance to Cry2Ab. Consistent with this hypothesis, introduction of disruptive mutations in PgABCA2 in a susceptible strain of pink bollworm increased the frequency of resistance to Cry2Ab and facilitated creation of a Cry2Ab-resistant strain. All Cry2Ab-resistant individuals tested in this study had disruptive mutations in PgABCA2. Overall, we found 17 different disruptive mutations in PgABCA2 gDNA and 26 in PgABCA2 cDNA, including novel mutations corresponding precisely to single-guide (sgRNA) sites used for CRISPR/Cas9. Together with previous results, these findings provide the first case of practical resistance to Cry2Ab where evidence identifies a specific gene in which disruptive mutations can cause resistance and are associated with resistance in field-selected populations.
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9
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Wei J, Yao X, Yang S, Liu S, Zhou S, Cen J, Liu X, Du M, Tang Q, An S. Suppression of Calcineurin Enhances the Toxicity of Cry1Ac to Helicoverpa armigera. Front Microbiol 2021; 12:634619. [PMID: 33643268 PMCID: PMC7904703 DOI: 10.3389/fmicb.2021.634619] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 01/25/2021] [Indexed: 12/14/2022] Open
Abstract
Insect resistance to Bacillus thuringiensis (Bt) insecticidal proteins has rapidly evolved with the expansion of the planting area of transgenic Bt crops. Pyramiding RNA interference (RNAi) and Bt in crops is urgently needed to counter the rapid increase in pest resistance. The ideal “pyramid” strategy simultaneously targets different action pathways that exert synergetic effects on each other. Here, we identified a dephosphatase, namely, Helicoverpa armigera calcineurin (HaCAN), which might enhance the insecticidal activity of Cry1Ac against Helicoverpa armigera by regulating immune gene expression via dephosphatase activity, but not by acting as a receptor. Notably, blocking enzyme activity or knocking down endogenous HaCAN significantly promoted the enhancement in Cry1Ac toxicity to insect larvae and cells. Correspondingly, the increase in HaCAN activity reduced the cytotoxicity of Cry1Ac as shown by the heterologous expression of HaCAN. Our results provide a probable that HaCAN is an important candidate gene for pyramiding RNAi and Cry1Ac crops to control cotton bollworm.
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Affiliation(s)
- Jizhen Wei
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xue Yao
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shuo Yang
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shaokai Liu
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shuai Zhou
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Junjuan Cen
- Bureau of Agriculture and Rural Affairs of Qixian, Kaifeng, China
| | - Xiaoguang Liu
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Mengfang Du
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Qingbo Tang
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shiheng An
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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10
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Transgenic cotton and sterile insect releases synergize eradication of pink bollworm a century after it invaded the United States. Proc Natl Acad Sci U S A 2020; 118:2019115118. [PMID: 33443170 DOI: 10.1073/pnas.2019115118] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Invasive organisms pose a global threat and are exceptionally difficult to eradicate after they become abundant in their new habitats. We report a successful multitactic strategy for combating the pink bollworm (Pectinophora gossypiella), one of the world's most invasive pests. A coordinated program in the southwestern United States and northern Mexico included releases of billions of sterile pink bollworm moths from airplanes and planting of cotton engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). An analysis of computer simulations and 21 y of field data from Arizona demonstrate that the transgenic Bt cotton and sterile insect releases interacted synergistically to reduce the pest's population size. In Arizona, the program started in 2006 and decreased the pest's estimated statewide population size from over 2 billion in 2005 to zero in 2013. Complementary regional efforts eradicated this pest throughout the cotton-growing areas of the continental United States and northern Mexico a century after it had invaded both countries. The removal of this pest saved farmers in the United States $192 million from 2014 to 2019. It also eliminated the environmental and safety hazards associated with insecticide sprays that had previously targeted the pink bollworm and facilitated an 82% reduction in insecticides used against all cotton pests in Arizona. The economic and social benefits achieved demonstrate the advantages of using agricultural biotechnology in concert with classical pest control tactics.
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11
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Baranek J, Pogodziński B, Szipluk N, Zielezinski A. TOXiTAXi: a web resource for toxicity of Bacillus thuringiensis protein compositions towards species of various taxonomic groups. Sci Rep 2020; 10:19767. [PMID: 33188218 PMCID: PMC7666212 DOI: 10.1038/s41598-020-75932-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/29/2020] [Indexed: 11/20/2022] Open
Abstract
Bioinsecticides consisting of different sets of Bacillus thuringiensis (Bt) Cry, Cyt and Vip toxins are broadly used in pest control. Possible interactions (synergistic, additive or antagonistic) between these proteins can not only influence the overall efficacy of certain Bt-based bioinsecticide, but also raise questions regarding environmental safety. Here, we assemble, summarize and analyze the outcomes of experiments published over 30 years, investigating combinatorial effects among Bt Cry, Cyt and Vip toxins. We collected the results on 118 various two-to-five-component combinations that have been bioassayed against 38 invertebrate species. Synergism, additive effect and antagonism was indicated in 54%, 32% and 14% of experiments, respectively. Synergism was noted most frequently for Cry/Cyt combinations, followed by Cyt/Vip and Cry/Cry. In Cry/Vip combinations, antagonism is more frequent and higher in magnitude compared to other categories. Despite a significant number of tested Bt toxin combinations, most of them have been bioassayed only against one pest species. To aid the research on Bt pesticidal protein activity, we present TOXiTAXi ( http://www.combio.pl/toxitaxi/ ), a universal database and a dedicated web tool to conveniently gather and analyze the existing and future bioassay results on biocidal activity of toxins against various taxonomic groups.
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Affiliation(s)
- Jakub Baranek
- Department of Microbiology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland.
| | - Bartłomiej Pogodziński
- Department of Computational Biology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Norbert Szipluk
- Department of Microbiology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Andrzej Zielezinski
- Department of Computational Biology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
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Lawrie RD, Mitchell III RD, Deguenon JM, Ponnusamy L, Reisig D, Pozo-Valdivia AD, Kurtz RW, Roe RM. Multiple Known Mechanisms and a Possible Role of an Enhanced Immune System in Bt-Resistance in a Field Population of the Bollworm, Helicoverpa zea: Differences in Gene Expression with RNAseq. Int J Mol Sci 2020; 21:E6528. [PMID: 32906662 PMCID: PMC7555151 DOI: 10.3390/ijms21186528] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/01/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022] Open
Abstract
Several different agricultural insect pests have developed field resistance to Bt (Bacillus thuringiensis) proteins (ex. Cry1Ac, Cry1F, etc.) expressed in crops, including corn and cotton. In the bollworm, Helicoverpa zea, resistance levels are increasing; recent reports in 2019 show up to 1000-fold levels of resistance to Cry1Ac, a major insecticidal protein in Bt-crops. A common method to analyze global differences in gene expression is RNA-seq. This technique was used to measure differences in global gene expression between a Bt-susceptible and Bt-resistant strain of the bollworm, where the differences in susceptibility to Cry1Ac insecticidal proteins were 100-fold. We found expected gene expression differences based on our current understanding of the Bt mode of action, including increased expression of proteases (trypsins and serine proteases) and reduced expression of Bt-interacting receptors (aminopeptidases and cadherins) in resistant bollworms. We also found additional expression differences for transcripts that were not previously investigated, i.e., transcripts from three immune pathways-Jak/STAT, Toll, and IMD. Immune pathway receptors (ex. PGRPs) and the IMD pathway demonstrated the highest differences in expression. Our analysis suggested that multiple mechanisms are involved in the development of Bt-resistance, including potentially unrecognized pathways.
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Affiliation(s)
- Roger D. Lawrie
- Department of Biology/Environmental and Molecular Toxicology Program, 850 Main Campus Dr, North Carolina State University, Raleigh, NC 27695, USA;
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (L.P.)
| | - Robert D. Mitchell III
- Knipling-Bushland US Livestock Insects Research Laboratory Genomics Center, 2700 Fredericksburg Road, United States Department of Agriculture-Agricultural Research Service, Kerrville, TX 78028, USA;
| | - Jean Marcel Deguenon
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (L.P.)
| | - Loganathan Ponnusamy
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (L.P.)
| | - Dominic Reisig
- Department of Entomology and Plant Pathology, Vernon G. James Research & Extension Center, 207 Research Station Road, Plymouth, NC 27962, USA; (D.R.); (A.D.P.-V.)
| | - Alejandro Del Pozo-Valdivia
- Department of Entomology and Plant Pathology, Vernon G. James Research & Extension Center, 207 Research Station Road, Plymouth, NC 27962, USA; (D.R.); (A.D.P.-V.)
| | - Ryan W. Kurtz
- Cotton Incorporated, 6399 Weston Parkway, Cary, NC 27513, USA;
| | - R. Michael Roe
- Department of Biology/Environmental and Molecular Toxicology Program, 850 Main Campus Dr, North Carolina State University, Raleigh, NC 27695, USA;
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (L.P.)
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13
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Fabrick JA, LeRoy DM, Unnithan GC, Yelich AJ, Carrière Y, Li X, Tabashnik BE. Shared and Independent Genetic Basis of Resistance to Bt Toxin Cry2Ab in Two Strains of Pink Bollworm. Sci Rep 2020; 10:7988. [PMID: 32409635 PMCID: PMC7224296 DOI: 10.1038/s41598-020-64811-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/22/2020] [Indexed: 12/20/2022] Open
Abstract
Evolution of pest resistance threatens the benefits of crops genetically engineered to produce insecticidal proteins from Bacillus thuringiensis (Bt). Field populations of the pink bollworm (Pectinophora gossypiella), a global pest of cotton, have evolved practical resistance to transgenic cotton producing Bt toxin Cry2Ab in India, but not in the United States. Previous results show that recessive mutations disrupting an autosomal ATP-binding cassette gene (PgABCA2) are associated with pink bollworm resistance to Cry2Ab in field-selected populations from India and in one lab-selected strain from the United States (Bt4-R2). Here we discovered that an independently derived, lab-selected Cry2Ab-resistant pink bollworm strain from the United States (BX-R) also harbors mutations that disrupt PgABCA2. Premature stop codons introduced by mis-splicing of PgABCA2 pre-mRNA were prevalent in field-selected larvae from India and in both lab-selected strains. The most common mutation in field-selected larvae from India was also detected in both lab-selected strains. Results from interstrain crosses indicate BX-R has at least one additional mechanism of resistance to Cry2Ab that does not involve PgABCA2 and is not completely recessive or autosomal. We conclude that recessive mutations disrupting PgABCA2 are the primary, but not the only, mechanism of resistance to Cry2Ab in pink bollworm.
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Affiliation(s)
- Jeffrey A Fabrick
- USDA ARS, U.S. Arid Land Agricultural Research Center, Maricopa, AZ, 85138, USA.
| | - Dannialle M LeRoy
- USDA ARS, U.S. Arid Land Agricultural Research Center, Maricopa, AZ, 85138, USA
| | | | - Alex J Yelich
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA
| | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA
| | - Xianchun Li
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA
| | - Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA
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Wang J, Xu D, Wang L, Cong S, Wan P, Lei C, Fabrick JA, Li X, Tabashnik BE, Wu K. Bt resistance alleles in field populations of pink bollworm from China: Similarities with the United States and decreased frequency from 2012 to 2015. PEST MANAGEMENT SCIENCE 2020; 76:527-533. [PMID: 31270942 DOI: 10.1002/ps.5541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/01/2019] [Accepted: 07/01/2019] [Indexed: 05/29/2023]
Abstract
BACKGROUND Although most monitoring of pest resistance to widely cultivated transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) relies on bioassays, DNA screening for alleles associated with resistance has some advantages, particularly for rare, recessively inherited resistance. In China's Yangtze River Valley, where farmers first planted transgenic cotton producing Bt toxin Cry1Ac in 2000, bioassays have been used to monitor the recessive resistance of pink bollworm (Pectinophora gossypiella). Previous bioassay results show a small but significant increase in resistance to Cry1Ac during 2008-2010, followed by a significant decrease in resistance during 2011-2015 associated with extensive planting of second-generation hybrid cotton seeds that boosted the percentage of non-Bt cotton. Here we screened DNA from 19 748 pink bollworm collected during 2012-2015 from the Yangtze River Valley for seven alleles associated with resistance to Cry1Ac. These alleles were previously identified from lab-selected strains; three from the U.S. and four from China. RESULTS The most common resistance allele was first identified from the U.S. and accounted for over 71% of all resistance alleles detected. Resistance was rare, with the total frequency of the seven resistance alleles showing a significant, 2.3-fold decrease from 0.0105 (95% CI: 0.0084-0.0132) in 2012 to 0.0046 (0.0031-0.0067) in 2015. CONCLUSIONS The DNA screening data confirm results from bioassays showing pink bollworm resistance to Cry1Ac remained rare in the Yangtze River Valley from 2012-2015. The prevalence in China of the resistance allele identified from the U.S. implies a shared genetic basis of resistance that could facilitate molecular monitoring of resistance. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Jintao Wang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Dong Xu
- Key laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Ling Wang
- Key laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Shengbo Cong
- Key laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Peng Wan
- Key laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Chaoliang Lei
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jeffrey A Fabrick
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Arid Land Agricultural Research Center, Maricopa, AZ, USA
| | - Xianchun Li
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| | | | - Kongming Wu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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Botha A, Kunert KJ, Maling’a J, Foyer CH. Defining biotechnological solutions for insect control in sub‐Saharan Africa. Food Energy Secur 2020. [DOI: 10.1002/fes3.191] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Anna‐Maria Botha
- Department of Genetics Stellenbosch University Stellenbosch South Africa
| | - Karl J. Kunert
- Department of Plant Sciences FABI University of Pretoria Pretoria South Africa
| | - Joyce Maling’a
- Kenya Agriculture and Livestock Organization (KALRO) Food Crops Research Institute Kitale Kenya
| | - Christine H. Foyer
- School of Biosciences College of Life and Environmental Sciences University of Birmingham, Edgbaston Birmingham UK
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16
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Tabashnik BE, Carrière Y. Global Patterns of Resistance to Bt Crops Highlighting Pink Bollworm in the United States, China, and India. JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:2513-2523. [PMID: 31254345 DOI: 10.1093/jee/toz173] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Indexed: 05/29/2023]
Abstract
Crops genetically engineered to produce insecticidal proteins from Bacillus thuringiensis (Bt) have advanced pest control, but their benefits have been reduced by evolution of resistance in pests. The global monitoring data reviewed here reveal 19 cases of practical resistance to Bt crops, which is field-evolved resistance that reduces Bt crop efficacy and has practical consequences for pest control. Each case represents the responses of one pest species in one country to one Bt toxin. The results with pink bollworm (Pectinophora gossypiella) and Bt cotton differ strikingly among the world's three leading cotton-producing nations. In the southwestern United States, farmers delayed resistance by planting non-Bt cotton refuges from 1996 to 2005, then cooperated in a program that used Bt cotton, mass releases of sterile moths, and other tactics to eradicate this pest from the region. In China, farmers reversed low levels of pink bollworm resistance to Bt cotton by planting second-generation hybrid seeds from crosses between Bt and non-Bt cotton. This approach yields a refuge of 25% non-Bt cotton plants randomly interspersed within fields of Bt cotton. Farmers adopted this tactic voluntarily and unknowingly, not to manage resistance, but apparently because of its perceived short-term agronomic and economic benefits. In India, where non-Bt cotton refuges have been scarce and pink bollworm resistance to pyramided Bt cotton producing Cry1Ac and Cry2Ab toxins is widespread, integrated pest management emphasizing shortening of the cotton season, destruction of crop residues, and other tactics is now essential.
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Affiliation(s)
| | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ
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17
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Naik VC, Kumbhare S, Kranthi S, Satija U, Kranthi KR. Field-evolved resistance of pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), to transgenic Bacillus thuringiensis (Bt) cotton expressing crystal 1Ac (Cry1Ac) and Cry2Ab in India. PEST MANAGEMENT SCIENCE 2018; 74:2544-2554. [PMID: 29697187 DOI: 10.1002/ps.5038] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 05/29/2023]
Abstract
BACKGROUND Pink bollworm (PBW) adaptation to transgenic Bacillus thuringiensis (Bt) cotton expressing crystal 1Ac (Cry1Ac) (Bt-I) and Cry1Ac + Cry2Ab (Bt-II) was assessed in India during 2010-2017 in 38 districts of the 10 major cotton-growing states. RESULTS PBW larval incidence on Bt cotton was nil in northern India, wherein the resistance ratios (RRs) to Cry1Ac were 26-262 and those to Cry2Ab were 1-108. In central and southern India, the annual average PBW larval recovery from Bt II cotton was high at 28.85-72.49% during 2014-2017. In central and southern India, the 50% lethal concentration (LC50 ) of Cry1Ac increased from a mean of 0.330 µg mL-1 (range 0.126-0.849 µg mL-1 ) in 2013 to a mean of 6.938 µg mL-1 (range 3.52 to 10.30 µg mL-1 ) in 2017 and the RR increased from a mean of 47.12 (range 18-121) in 2013 to a mean of 1387 (704-2060) in 2017, whereas the LC50 value for Cry2Ab increased from a mean of 0.014 µg mL-1 (range 0.004-0.094 µg mL-1 ) in 2013 to a mean of 12.51 µg mL-1 (range 3.92 to 28.10 µg mL-1 ) in 2017 and the RR increased from a mean of 5.4 (range 1-31) in 2013 to a mean of 4196 (1306-9366) in 2017. CONCLUSION High PBW larval recovery on Bt-II in conjunction with high LC50 values for Cry1Ac and Cry2Ab in major cotton-growing districts of central and southern India provides evidence of field-evolved resistance in PBW to Bt-I and Bt-II cotton. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Vakudavath Cb Naik
- Crop Protection Division, Central Institute for Cotton Research, Nagpur, India
| | - Sujit Kumbhare
- Crop Protection Division, Central Institute for Cotton Research, Nagpur, India
| | - Sandhya Kranthi
- Crop Protection Division, Central Institute for Cotton Research, Nagpur, India
| | - Usha Satija
- Crop Protection Division, Central Institute for Cotton Research, Nagpur, India
| | - Keshav R Kranthi
- Crop Protection Division, Central Institute for Cotton Research, Nagpur, India
- Technical Information Section, International Cotton Advisory Committee, Washington, DC, USA
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18
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ABC transporter mis-splicing associated with resistance to Bt toxin Cry2Ab in laboratory- and field-selected pink bollworm. Sci Rep 2018; 8:13531. [PMID: 30202031 PMCID: PMC6131251 DOI: 10.1038/s41598-018-31840-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/28/2018] [Indexed: 11/13/2022] Open
Abstract
Evolution of pest resistance threatens the benefits of genetically engineered crops that produce Bacillus thuringiensis (Bt) insecticidal proteins. Strategies intended to delay pest resistance are most effective when implemented proactively. Accordingly, researchers have selected for and analyzed resistance to Bt toxins in many laboratory strains of pests before resistance evolves in the field, but the utility of this approach depends on the largely untested assumption that laboratory- and field-selected resistance to Bt toxins are similar. Here we compared the genetic basis of resistance to Bt toxin Cry2Ab, which is widely deployed in transgenic crops, between laboratory- and field-selected populations of the pink bollworm (Pectinophora gossypiella), a global pest of cotton. We discovered that resistance to Cry2Ab is associated with mutations disrupting the same ATP-binding cassette transporter gene (PgABCA2) in a laboratory-selected strain from Arizona, USA, and in field-selected populations from India. The most common mutation, loss of exon 6 caused by alternative splicing, occurred in resistant larvae from both locations. Together with previous data, the results imply that mutations in the same gene confer Bt resistance in laboratory- and field-selected strains and suggest that focusing on ABCA2 genes may help to accelerate progress in monitoring and managing resistance to Cry2Ab.
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Chen L, Wei J, Liu C, Zhang W, Wang B, Niu L, Liang G. Specific Binding Protein ABCC1 Is Associated With Cry2Ab Toxicity in Helicoverpa armigera. Front Physiol 2018; 9:745. [PMID: 29971014 PMCID: PMC6018205 DOI: 10.3389/fphys.2018.00745] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/28/2018] [Indexed: 01/10/2023] Open
Abstract
A pyramid strategy combining the crystal (Cry) 1A and 2A toxins in Bacillus thuringiensis (Bt) crops are active against many species of insects and nematode larvae. It has been widely used to delay pest adaption to genetically modified plants and broaden the insecticidal spectrum in many countries. Unfortunately, Cry2A can also bind with the specific receptor proteins of Cry1A. ATP-binding cassette (ABC) transporters can interact with Cry1A toxins as receptors in the insect midgut, and ABC transporter mutations result in resistance to Bt proteins. However, there is limited knowledge of the ABC transporters that specifically bind to Cry2Ab. Here, we cloned the ABCC1 gene in Helicoverpa armigera, which expressed at all larval stages and in nine different tissues. Expression levels were particularly high in fifth-instar larvae and Malpighian tubules. The two heterologously expressed HaABCC1 transmembrane domain peptides could specifically bind to Cry2Ab with high affinity levels. Moreover, transfecting HaABCC1 into the Spodoptera frugiperda nine insect cell significantly increased its mortality when exposed to Cry2Ab in vitro, and silencing HaABCC1 in H. armigera by RNA interference significantly reduced the mortality of larvae exposed to Cry2Ab in vivo. Altogether current results suggest that HaABCC1 serves as a functional receptor for Cry2Ab.
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Affiliation(s)
- Lin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jizhen Wei
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Chen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wanna Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bingjie Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - LinLin Niu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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20
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Zhao M, Li Y, Yuan X, Liang G, Wang B, Liu C, Khaing MM. Establishment of a dietary exposure assay for evaluating the toxicity of insecticidal compounds to Apolygus lucorum (Hemiptera: Miridae). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:414-423. [PMID: 29502004 DOI: 10.1016/j.envpol.2018.01.012] [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: 04/01/2017] [Revised: 11/16/2017] [Accepted: 01/05/2018] [Indexed: 06/08/2023]
Abstract
With the commercialization of transgenic cotton that expresses Bt (Bacillus thuringiensis) insecticidal proteins, mirid bugs have become key pests in cotton and maize fields in China. Genetically engineered (GE) crops for controlling mirids are unavailable owing to a lack of suitable insecticidal genes. In this study, we developed and validated a dietary exposure assay for screening insecticidal compounds and for assessing the potential effects of insecticidal proteins produced by GE plants on Apolygus lucorum, one of the main mirid pests of Bt cotton and Bt maize. Diets containing potassium arsenate (PA) or the cysteine protease inhibitor E-64 were used as positive controls for validating the efficacy of the dietary exposure assay. The results showed that with increasing concentrations of PA or E-64, A. lucorum larval development time was prolonged and adult weight and fecundity were decreased, suggesting that the dietary exposure assay was useful for detecting the toxicity of insecticidal compounds to A. lucorum. This assay was then used to assess the toxicity of Cry1Ab, Cry1Ac, Cry1F, Cry2Aa, and Cry2Ab proteins, which have been transformed into several crops, against A. lucorum. The results showed that A. lucorum did not show a negative effect by feeding on an artificial diet containing any of the purified Cry proteins. No significant changes in the activities of digestive, detoxifying, or antioxidant enzymes were detected in A. lucorum that fed on a diet containing Cry proteins, but A. lucorum fitness was reduced when the insect fed on a diet containing E-64 or PA. These results demonstrate that A. lucorum is not sensitive to the tested Cry proteins and that the dietary exposure assay is useful for evaluating the toxicity of insecticidal compounds to this species.
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Affiliation(s)
- Man Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Yunhe Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xiangdong Yuan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
| | - Bingjie Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Chen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Myint Myint Khaing
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
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Expression of hybrid fusion protein (Cry1Ac::ASAL) in transgenic rice plants imparts resistance against multiple insect pests. Sci Rep 2018; 8:8458. [PMID: 29855556 PMCID: PMC5981619 DOI: 10.1038/s41598-018-26881-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/21/2018] [Indexed: 12/18/2022] Open
Abstract
To evolve rice varieties resistant to different groups of insect pests a fusion gene, comprising DI and DII domains of Bt Cry1Ac and carbohydrate binding domain of garlic lectin (ASAL), was constructed. Transgenic rice lines were generated and evaluated to assess the efficacy of Cry1Ac::ASAL fusion protein against three major pests, viz., yellow stem borer (YSB), leaf folder (LF) and brown planthopper (BPH). Molecular analyses of transgenic plants revealed stable integration and expression of the fusion gene. In planta insect bioassays on transgenics disclosed enhanced levels of resistance compared to the control plants. High insect mortality of YSB, LF and BPH was observed on transgenics compared to that of control plants. Furthermore, honeydew assays revealed significant decreases in the feeding ability of BPH on transgenic plants as compared to the controls. Ligand blot analysis, using BPH insects fed on cry1Ac::asal transgenic rice plants, revealed a modified receptor protein-binding pattern owing to its ability to bind to additional receptors in insects. The overall results authenticate that Cry1Ac::ASAL protein is endowed with remarkable entomotoxic effects against major lepidopteran and hemipteran insects. As such, the fusion gene appears promising and can be introduced into various other crops to control multiple insect pests.
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Walters FS, Graser G, Burns A, Raybould A. When the Whole is Not Greater than the Sum of the Parts: A Critical Review of Laboratory Bioassay Effects Testing for Insecticidal Protein Interactions. ENVIRONMENTAL ENTOMOLOGY 2018; 47:484-497. [PMID: 29432611 PMCID: PMC5888968 DOI: 10.1093/ee/nvx207] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Many studies have been conducted to investigate synergism among insecticidal proteins; however, a consensus on minimal data requirements and interpretation is lacking. While some have concluded that all additive predictive-type models should be abandoned, we advocate that additivity models can remain useful as assessment tools and that an appropriately designed interaction study will never systematically underestimate the existence of synergism, irrespective of which additivity model (or none at all) may be used. To generate the most meaningful synergy assessment datasets in support of safety assessments, we highlight two beneficial steps to follow: (i) select a testing model which is the most consistent with current knowledge regarding the action of the insecticidal proteins and (ii) avoid using bioassay methods which may result in excess response heterogeneity. We also outline other experimental design elements to consider, which may be crucial for conducting future studies of this type. A contrast of underlying testing assumptions associated with the additivity models is provided, along with a comprehensive review of interaction data for Cry1, Cry2, Cry3, Cry9, and Vip3A insecticidal proteins. Our review captures four recurrent findings: i) experiments reporting synergistic interactions are a minority, ii) the degree of synergism reported is low in magnitude, iii) reported interactions are sometimes equivocal/inconclusive due to unconfirmed model assumptions or other bioassay challenges, and iv) due to biological response variation many of the reported interactions may be artefactual. A brief overview of the positioning of interaction testing data in safety assessments of GM food crops is also provided.
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Affiliation(s)
| | - Gerson Graser
- Syngenta Crop Protection, LLC, Davis Drive, Durham, NC, USA
| | - Andrea Burns
- Syngenta Crop Protection, LLC, Davis Drive, Durham, NC, USA
| | - Alan Raybould
- Syngenta Crop Protection AG, Schwarzwaldallee, Basel, Switzerl
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Transgenic cotton co-expressing chimeric Vip3AcAa and Cry1Ac confers effective protection against Cry1Ac-resistant cotton bollworm. Transgenic Res 2017; 26:763-774. [DOI: 10.1007/s11248-017-0048-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 10/21/2017] [Indexed: 11/25/2022]
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24
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Surge in insect resistance to transgenic crops and prospects for sustainability. Nat Biotechnol 2017; 35:926-935. [DOI: 10.1038/nbt.3974] [Citation(s) in RCA: 344] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 08/25/2017] [Indexed: 12/25/2022]
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Shah JV, Yadav R, Ingle SS. Engineered Cry1Ac-Cry9Aa hybrid Bacillus thuringiensis delta-endotoxin with improved insecticidal activity against Helicoverpa armigera. Arch Microbiol 2017; 199:1069-1075. [PMID: 28685236 DOI: 10.1007/s00203-017-1407-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 04/14/2017] [Accepted: 06/28/2017] [Indexed: 10/19/2022]
Abstract
Recombinant Bt construct was prepared by exchange of pore forming domain I with cry1Ac to cry9Aa gene by overlap extension PCR (OE-PCR) technique. Construction of cry1Ac-cry9Aa was accomplished by six base pair homology at 3' ends of PCR products of domain I of cry1Ac and domain II and III of cry9Aa. The recombinant toxin was also modified by deletion of N-terminal alpha helix-1 of recombinant toxin. Both Cry toxins were expressed in E. coli BL21(DE3) plysS and purified by His-tag purification. Upon insect bioassay analysis against devastating crop pest Helicoverpa armigera, toxicity of recombinant toxin was found around fivefold higher than native Cry1Ac while alpha helix-1 deleted N-terminal modified toxin did not resulted in significant increase in toxicity. The recombinant Cry toxins such as Cry1Ac-Cry9Aa and Cry1Ac-Cry9AaMod may be used for insect pest control.
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Affiliation(s)
- Jigar V Shah
- Ground Floor Lab, Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India
| | - Rakeshkumar Yadav
- Ground Floor Lab, Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India
| | - Sanjay S Ingle
- Ground Floor Lab, Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India.
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Zhao M, Yuan X, Wei J, Zhang W, Wang B, Myint Khaing M, Liang G. Functional roles of cadherin, aminopeptidase-N and alkaline phosphatase from Helicoverpa armigera (Hübner) in the action mechanism of Bacillus thuringiensis Cry2Aa. Sci Rep 2017; 7:46555. [PMID: 28488696 PMCID: PMC5424343 DOI: 10.1038/srep46555] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 03/17/2017] [Indexed: 11/08/2022] Open
Abstract
A pyramid strategy combining the Cry1A and Cry2A toxins in Bt crops has been widely used throughout the world to delay pest adaption to transgenic crops and broaden the insecticidal spectrum. Midgut membrane-bound cadherin (CAD), aminopeptidase-N (APN) and alkaline phosphatase (ALP) are important for Cry1A toxicity in some lepidopteran larvae, but the proteins that bind Cry2A in the midgut of target insects and their role in the Cry2A mechanism of action are still unclear. In this study, we found that heterologously expressed CAD, APN4 and ALP2 peptides from the midgut of Helicoverpa armigera could bind to the Cry2Aa toxin with a high affinity. Additionally, the efficiency of Cry2Aa insecticidal activity against H. armigera larvae was obviously reduced after the genes encoding these proteins were silenced with specific siRNAs: CAD- and ALP2-silenced larvae showed significantly similar reductions in mortality due to the Cry2Aa toxin (41.67% and 43.06%, respectively), whereas a larger reduction in mortality was observed in APN4-silenced larvae (61.11%) than in controls. These results suggest that CAD, APN4 and ALP2 are involved in the mechanism of action of Cry2Aa in H. armigera and may play important functional roles in the toxicity of the Cry2Aa toxin.
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Affiliation(s)
- Man Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiangdong Yuan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jizhen Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wanna Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bingjie Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Myint Myint Khaing
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Then C, Bauer-Panskus A. Possible health impacts of Bt toxins and residues from spraying with complementary herbicides in genetically engineered soybeans and risk assessment as performed by the European Food Safety Authority EFSA. ENVIRONMENTAL SCIENCES EUROPE 2017; 29:1. [PMID: 28133586 PMCID: PMC5236067 DOI: 10.1186/s12302-016-0099-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 12/15/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND MON89788 was the first genetically engineered soybean worldwide to express a Bt toxin. Under the brand name Intacta, Monsanto subsequently engineered a stacked trait soybean using MON89788 and MON87701-this stacked soybean expresses an insecticidal toxin and is, in addition, tolerant to glyphosate. After undergoing risk assessment by the European Food Safety Authority (EFSA), the stacked event was authorised for import into the EU in June 2012, including for use in food and feed. This review discusses the health risks associated with Bt toxins present in these genetically engineered plants and the residues left from spraying with the complementary herbicide. RESULTS We have compared the opinion published by EFSA [1] with findings from other publications in the scientific literature. It is evident that there are several issues that EFSA did not consider in detail and which will need further assessment: (1) There are potential combinatorial effects between plant components and other impact factors that might enhance toxicity. (2) It is known that Bt toxins have immunogenic properties; since soybeans naturally contain many allergens, these immunogenic properties raise specific questions. (3) Fully evaluated and reliable protocols for measuring the Bt concentration in the plants are needed, in addition to a comprehensive set of data on gene expression under varying environmental conditions. (4) Specific attention should be paid to the herbicide residues and their interaction with Bt toxins. CONCLUSIONS The case of the Intacta soybeans highlights several regulatory problems with Bt soybean plants in the EU. Moreover, many of the issues raised also concern other genetically engineered plants that express insecticidal proteins, or are engineered to be resistant to herbicides, or have those two types of traits combined in stacked events. It remains a matter of debate whether the standards currently applied by the risk assessor, EFSA, and the risk manager, the EU Commission, meet the standards for risk analysis defined in EU regulations such as 1829/2003 and Directive 2001/18. While this publication cannot provide a final conclusion, it allows the development of some robust hypotheses that should be investigated further before such plants can be considered to be safe for health and the environment. In general, the concept of comparative risk assessment needs some major revision. Priority should be given to developing more targeted approaches. As shown in the case of Intacta, these approaches should include: (i) systematic investigation of interactions between the plant genome and environmental stressors as well as their impact on gene expression and plant composition; (ii) detailed investigations of the toxicity of Bt toxins; (iii) assessment of combinatorial effects taking into account long-term effects and the residues from spraying with complementary herbicides; (iv) investigation into the impact on the immune and hormonal systems and (v) investigation of the impact on the intestinal microbiome after consumption. Further and in general, stacked events displaying a high degree of complexity due to possible interactions should not undergo a lower level of risk assessment than the parental plants.
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Affiliation(s)
- Christoph Then
- Testbiotech, Institute for Independent Impact Assessment in Biotechnology, Frohschammerstr. 14, 80807 Munich, Germany
| | - Andreas Bauer-Panskus
- Testbiotech, Institute for Independent Impact Assessment in Biotechnology, Frohschammerstr. 14, 80807 Munich, Germany
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Katara JL, Kaur S, Kumari GK, Singh NK. Prevalence of cry2-type genes in Bacillus thuringiensis isolates recovered from diverse habitats in India and isolation of a novel cry2Af2 gene toxic to Helicoverpa armigera (cotton boll worm). Can J Microbiol 2016; 62:1003-1012. [DOI: 10.1139/cjm-2016-0042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Insecticidal cry and vip genes from Bacillus thuringiensis (Bt) have been used for control of lepidopteran insects in transgenic crops. However, novel genes are required for gene pyramiding to delay evolution of resistance to the currently deployed genes. Two PCR-based techniques were employed for screening of cry2-type genes in 129 Bt isolates from diverse habitats in India and 27 known Bt strains. cry2Ab-type genes were more prevalent than cry2Aa- and cry2Ac-type genes. Correlation between source of isolates and abundance of cry2-type genes was not observed. Full-length cry2A-type genes were amplified by PCR from 9 Bt isolates and 4 Bt strains. The genes from Bt isolates SK-758 from Sorghum grain dust and SK-793 from Chilli seeds warehouse, Andhra Pradesh, were cloned and sequenced. The gene from SK-758 (NCBI GenBank accession No. GQ866915) was novel, while that from SK-793 (NCBI GenBank accession No. GQ866914) was identical to the cry2Ab1 gene. The Bacillus thuringiensis Nomenclature Committee ( http://www.lifesci.sussex.ac.uk/home/Neil_Crickmore/Bt/toxins2.html ) named these genes cry2Af2 and cry2Ab16, respectively. The cry2Af2 gene was expressed in Escherichia coli and found to be toxic towards Helicoverpa armigera. The cry2Af2 gene will be useful for pyramiding in transgenic crops.
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Affiliation(s)
- Jawahar Lal Katara
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
| | - Sarvjeet Kaur
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
| | - Gouthami Krishna Kumari
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
| | - Nagendra Kumar Singh
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
- Indian Council of Agricultural Research (ICAR) – National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute Campus, New Delhi 110012, India
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Shi PJ, Wei JZ, Sandhu HS, Liang GM. Capturing the interaction types of two Bt toxins Cry1Ac and Cry2Ab on suppressing the cotton bollworm by using multi-exponential equations. INSECT SCIENCE 2016; 23:649-654. [PMID: 26314801 DOI: 10.1111/1744-7917.12273] [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] [Accepted: 07/07/2015] [Indexed: 06/04/2023]
Abstract
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.
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Affiliation(s)
- Pei-Jian Shi
- Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province, Bamboo Research Institute, Nanjing Forestry University, Nanjing, China
| | - Ji-Zhen Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hardev S Sandhu
- Institute of Food and Agricultural Sciences, Everglades Research and Education Center, University of Florida, Belle Glade, USA
| | - Ge-Mei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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Lombardo L, Coppola G, Zelasco S. New Technologies for Insect-Resistant and Herbicide-Tolerant Plants. Trends Biotechnol 2016; 34:49-57. [DOI: 10.1016/j.tibtech.2015.10.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/17/2022]
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Ocelotl J, Sánchez J, Arroyo R, García-Gómez BI, Gómez I, Unnithan GC, Tabashnik BE, Bravo A, Soberón M. Binding and Oligomerization of Modified and Native Bt Toxins in Resistant and Susceptible Pink Bollworm. PLoS One 2015; 10:e0144086. [PMID: 26633693 PMCID: PMC4669222 DOI: 10.1371/journal.pone.0144086] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 11/12/2015] [Indexed: 11/26/2022] Open
Abstract
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.
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Affiliation(s)
- Josue Ocelotl
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510–3, Cuernavaca, Mor. 62210, (Mexico)
| | - Jorge Sánchez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510–3, Cuernavaca, Mor. 62210, (Mexico)
| | - Raquel Arroyo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510–3, Cuernavaca, Mor. 62210, (Mexico)
| | - Blanca I. García-Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510–3, Cuernavaca, Mor. 62210, (Mexico)
| | - Isabel Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510–3, Cuernavaca, Mor. 62210, (Mexico)
| | - Gopalan C. Unnithan
- Department of Entomology, University of Arizona, Tucson, Arizona, 85721, United States of America
| | - Bruce E. Tabashnik
- Department of Entomology, University of Arizona, Tucson, Arizona, 85721, United States of America
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510–3, Cuernavaca, Mor. 62210, (Mexico)
- * E-mail: (MS); (AB)
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510–3, Cuernavaca, Mor. 62210, (Mexico)
- * E-mail: (MS); (AB)
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Fabrick JA, Unnithan GC, Yelich AJ, DeGain B, Masson L, Zhang J, Carrière Y, Tabashnik BE. Multi-Toxin Resistance Enables Pink Bollworm Survival on Pyramided Bt Cotton. Sci Rep 2015; 5:16554. [PMID: 26559899 PMCID: PMC5156061 DOI: 10.1038/srep16554] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/15/2015] [Indexed: 11/09/2022] Open
Abstract
Transgenic crops producing Bacillus thuringiensis (Bt) proteins kill key insect pests, providing economic and environmental benefits. However, the evolution of pest resistance threatens the continued success of such Bt crops. To delay or counter resistance, transgenic plant "pyramids" producing two or more Bt proteins that kill the same pest have been adopted extensively. Field populations of the pink bollworm (Pectinophora gossypiella) in the United States have remained susceptible to Bt toxins Cry1Ac and Cry2Ab, but field-evolved practical resistance to Bt cotton producing Cry1Ac has occurred widely in India. Here we used two rounds of laboratory selection to achieve 18,000- to 150,000-fold resistance to Cry2Ab in pink bollworm. Inheritance of resistance to Cry2Ab was recessive, autosomal, conferred primarily by one locus, and independent of Cry1Ac resistance. We created a strain with high resistance to both toxins by crossing the Cry2Ab-resistant strain with a Cry1Ac-resistant strain, followed by one selection with Cry2Ab. This multi-toxin resistant strain survived on field-collected Bt cotton bolls producing both toxins. The results here demonstrate the risk of evolution of resistance to pyramided Bt plants, particularly when toxins are deployed sequentially and refuges are scarce, as seen with Bt cotton and pink bollworm in India.
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Affiliation(s)
- Jeffrey A Fabrick
- USDA ARS, U.S. Arid Land Agricultural Research Center, Maricopa, AZ 85138 USA
| | | | - Alex J Yelich
- Department of Entomology, University of Arizona, Tucson, AZ 85721 USA
| | - Ben DeGain
- Department of Entomology, University of Arizona, Tucson, AZ 85721 USA
| | - Luke Masson
- Biotechnology Research Institute, National Research Council of Canada, Montreal, QC, Canada H4P 2R2
| | - Jie Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, Haidian District, 100193 Peoples Republic of China
| | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ 85721 USA
| | - Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, AZ 85721 USA
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Gómez I, Flores B, Bravo A, Soberón M. Bacillus thuringiensis Cry1AbMod toxin counters tolerance associated with low cadherin expression but not that associated with low alkaline phosphatase expression in Manduca sexta. Peptides 2015; 68:130-3. [PMID: 25239508 DOI: 10.1016/j.peptides.2014.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/15/2014] [Accepted: 08/19/2014] [Indexed: 12/25/2022]
Abstract
To exert their toxic effect, Bacillus thuringiensis Cry1Ab toxin undergoes a sequential binding mechanism with different larval gut proteins including glycosyl-phosphatidyl-inositol anchored proteins like aminopeptidase-N (APN) or alkaline-phosphatase (ALP) and a transmembrane cadherin to form pre-pore structures that insert into the membrane. Cadherin binding induces oligomerization of the toxin by facilitating removal of the N-terminal region, while APN/ALP binding helps in oligomer membrane insertion. Cry1AbMod toxin was engineered to lack N-terminal region of the toxin and shown to counter resistance linked to cadherin mutations. In this manuscript we determined the toxicity of Cry1AbMod to Manduca sexta larvae silenced in the expression of cadherin, ALP or APN receptors. As previously reported Cry1Ab toxicity relied principally in ALP and cadherin in comparison to APN. Our data shows that Cry1AbMod counters resistance associated with low cadherin expression but was not effective against ALP silenced larvae. These results show that Cry1AbMod could be effective against resistance insects linked to mutations on binding molecules involved in toxin oligomerization but not against resistant insects linked to mutations on binding molecules involved in oligomer membrane insertion.
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Affiliation(s)
- Isabel Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Biviana Flores
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico.
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A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera. PLoS One 2015; 10:e0126288. [PMID: 25885820 PMCID: PMC4401514 DOI: 10.1371/journal.pone.0126288] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 03/31/2015] [Indexed: 11/19/2022] Open
Abstract
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.
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35
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Wei J, Guo Y, Liang G, Wu K, Zhang J, Tabashnik BE, Li X. Cross-resistance and interactions between Bt toxins Cry1Ac and Cry2Ab against the cotton bollworm. Sci Rep 2015; 5:7714. [PMID: 25586723 PMCID: PMC4293620 DOI: 10.1038/srep07714] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 12/08/2014] [Indexed: 11/09/2022] Open
Abstract
To delay evolution of pest resistance to transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt), the "pyramid" strategy uses plants that produce two or more toxins that kill the same pest. We conducted laboratory diet experiments with the cotton bollworm, Helicoverpa armigera, to evaluate cross-resistance and interactions between two toxins in pyramided Bt cotton (Cry1Ac and Cry2Ab). Selection with Cry1Ac for 125 generations produced 1000-fold resistance to Cry1Ac and 6.8-fold cross-resistance to Cry2Ab. Selection with Cry2Ab for 29 generations caused 5.6-fold resistance to Cry2Ab and 61-fold cross-resistance to Cry1Ac. Without exposure to Bt toxins, resistance to both toxins decreased. For each of the four resistant strains examined, 67 to 100% of the combinations of Cry1Ac and Cry2Ab tested yielded higher than expected mortality, reflecting synergism between these two toxins. Results showing minor cross-resistance to Cry2Ab caused by selection with Cry1Ac and synergism between these two toxins against resistant insects suggest that plants producing both toxins could prolong the efficacy of Bt cotton against this pest in China. Including toxins against which no cross-resistance occurs and integrating Bt cotton with other control tactics could also increase the sustainability of management strategies.
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Affiliation(s)
- Jizhen Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yuyuan Guo
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Kongming Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jie Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA
| | - Xianchun Li
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA
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Li M, Zhu M, Zhang C, Liu X, Wan Y. Uniform orientation of biotinylated nanobody as an affinity binder for detection of Bacillus thuringiensis (Bt) Cry1Ac toxin. Toxins (Basel) 2014; 6:3208-22. [PMID: 25474492 PMCID: PMC4280530 DOI: 10.3390/toxins6123208] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 11/10/2014] [Accepted: 11/17/2014] [Indexed: 12/26/2022] Open
Abstract
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.
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Affiliation(s)
- Min Li
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Sipailou NO. 2, Southeast University, Nanjing 210096, China.
| | - Min Zhu
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Sipailou NO. 2, Southeast University, Nanjing 210096, China.
| | - Cunzheng Zhang
- Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - Xianjin Liu
- Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
| | - Yakun Wan
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Sipailou NO. 2, Southeast University, Nanjing 210096, China.
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