201
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Berlitz D, Giovenardi M, Charles JF, Fiúza L. Toxicity intraperitoneal and intragastric route of Bacillus thuringiensis and Melia azedarach in mice. ARQUIVOS DO INSTITUTO BIOLÓGICO 2012. [DOI: 10.1590/s1808-16572012000400007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The aim of this investigation was the assessment of toxicity of two new isolates of Bacillus thuringiensis, and the aqueous extract of Melia azedarach through in vivo assays in CF1 mice. Bt 1958-2, Bt 2014-2 and the BTh Thuricide 63 standard isolates were grown in liquid usual glicosed medium, and Cry proteins were purified by centrifugation on a sucrose gradient. The supernatant was autoclaved at 121º C, 15min. to maintain the exotoxins. Dehydrated leaves of M. azedarach were used to prepare a 10% aqueous extract. Mice were treated either orally or intraperitoneally with a whole bacterial suspension (1.10(10) UFC/mL), a culture supernatant or purified crystal protein (50 µg/mL), and with the plant extract (50 µg/mL). The stomachs of the mice were collected and observed in stereomicroscopy, and the stomach contents were analyzed in 10% SDS-PAGE. Results showed that none of the oral treatments were toxic to mice, but intraperitoneal bacterial suspensions were lethal to the animals 6 - 24 hours after injection. In conclusion, the Cry proteins of the new B. thuringiensis isolates must be evaluated for their use as tools in the biotechnology field, since they do not show toxicity against mammals, intragastrically or peritoneally, just like the M. azedarach aqueous extract (10%), with those being indicated for the biological control of pest insects.
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Affiliation(s)
| | - M. Giovenardi
- Universidade Federal de Ciências da Saúde de Porto Alegre, Brasil
| | | | - L.M. Fiúza
- Universidade do Vale do Rio dos Sinos, Brasil
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202
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Zhou Z, Pang J, Guo W, Zhong N, Tian Y, Xia G, Wu J. Evaluation of the resistance of transgenic potato plants expressing various levels of Cry3A against the Colorado potato beetle (Leptinotarsa decemlineata Say) in the laboratory and field. PEST MANAGEMENT SCIENCE 2012; 68:1595-1604. [PMID: 22807197 DOI: 10.1002/ps.3356] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 04/18/2012] [Accepted: 05/10/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND The Colorado potato beetle (CPB), Leptinotarsa decemlineata Say, is a destructive pest. The CPB is a quarantine pest in China, but has now invaded the Xinjiang Uygur Autonomous Region and is continuing to spread eastwards. To control the damage and overspreading, transgenic potato plants expressing Cry3A toxin were developed, and their resistance to CPB was evaluated by bioassays in the laboratory and field in 2009, 2010 and 2011. RESULTS The insect resistance of the high-dose (HD) transgenic lines was significantly greater than the middle-dose (MD) and low-dose (LD) transgenic lines regarding leaf consumption, biomass accumulation and mortality. The HD and MD transgenic lines showed 100% mortality when inoculated with first- and second-instar larvae; however, the LD transgenic lines showed about 50% mortality. The HD transgenic lines exhibited a significantly higher yield than the MD and LD transgenic lines owing to their high CPB resistance. CONCLUSION Commercially available transgenic potato plants with above 0.1% Cry3A of total soluble protein and NT control refugia could control damage, delay adaptation and halt dispersion eastwards. The two HD transgenic lines developed in this study, PAH1 and PAH2, are ideal for use as cultivars or germplasm to breed new cultivars.
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Affiliation(s)
- Zhaoxu Zhou
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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203
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Chakravarthy VSK, Reddy TP, Reddy VD, Rao KV. Current status of genetic engineering in cotton(Gossypium hirsutum L): an assessment. Crit Rev Biotechnol 2012. [DOI: 10.3109/07388551.2012.743502] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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204
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Gryspeirt A, Grégoire JC. Effectiveness of the high dose/refuge strategy for managing pest resistance to Bacillus thuringiensis (Bt) plants expressing one or two toxins. Toxins (Basel) 2012; 4:810-35. [PMID: 23162699 PMCID: PMC3496990 DOI: 10.3390/toxins4100810] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 09/21/2012] [Accepted: 10/08/2012] [Indexed: 11/30/2022] Open
Abstract
To delay resistance development to Bacillus thuringiensis (Bt) plants expressing their own insecticide, the application of the Insect Resistance Management strategy called "High Dose/Refuge Strategy" (HD/R) is recommended by the US Environmental Protection Agency (US EPA). This strategy was developed for Bt plants expressing one toxin. Presently, however, new Bt plants that simultaneously express two toxins are on the market. We used a mathematical model to evaluate the efficiency of the HD/R strategy for both these Bt toxins. As the current two-toxin Bt plants do not express two new Cry toxins but reuse one toxin already in use with a one-toxin plant, we estimated the spread of resistance when the resistance alleles are not rare. This study assesses: (i) whether the two toxins have to be present in high concentration, and (ii) the impact of the relative size of the refuge zone on the evolution of resistance and population density. We concluded that for Bt plants expressing one toxin, a high concentration is an essential condition for resistance management. For the pyramided Bt plants, one toxin could be expressed at a low titer if the two toxins are used for the first time, and a small refuge zone is acceptable.
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Affiliation(s)
- Aiko Gryspeirt
- Biological Control and Spatial Ecology Laboratory (LUBIES), CP 160/12, Université Libre de Bruxelles, av. FD Roosevelt 50, B-1050 Brussels, Belgium;
- Research Funding for Industry and Agriculture (FRIA, Fonds pour la Formation à la Recherche dans l’Industrie et l’Agriculture), 5 rue d’Egmont, B-1000 Brussels, Belgium
| | - Jean-Claude Grégoire
- Biological Control and Spatial Ecology Laboratory (LUBIES), CP 160/12, Université Libre de Bruxelles, av. FD Roosevelt 50, B-1050 Brussels, Belgium;
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205
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Vachon V, Laprade R, Schwartz JL. Current models of the mode of action of Bacillus thuringiensis insecticidal crystal proteins: A critical review. J Invertebr Pathol 2012; 111:1-12. [DOI: 10.1016/j.jip.2012.05.001] [Citation(s) in RCA: 283] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/01/2012] [Accepted: 05/03/2012] [Indexed: 12/29/2022]
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206
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Kozub NO, Pilipenko LA, Sozinov IO, Blume YB, Sozinov OO. Genetically modified plants and plant protection problems: Progress and estimation of potential risks. CYTOL GENET+ 2012. [DOI: 10.3103/s0095452712040081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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207
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Schuppener M, Mühlhause J, Müller AK, Rauschen S. Environmental risk assessment for the small tortoiseshell Aglais urticae and a stacked Bt-maize with combined resistances against Lepidoptera and Chrysomelidae in central European agrarian landscapes. Mol Ecol 2012; 21:4646-62. [PMID: 22861488 DOI: 10.1111/j.1365-294x.2012.05716.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cultivation of Lepidoptera-resistant Bt-maize may affect nontarget butterflies. We assessed the risk posed by event MON89034 × MON88017 (expressing Cry1A.105 and Cry2Ab2 against corn borers) to nontarget Lepidoptera. Using the small tortoiseshell Aglais urticae, a butterfly species common in central Europe, as a test organism we (i) assessed the toxicity of Bt-maize pollen on butterfly larvae; (ii) measured pollen deposition on leaves of the host plant Urtica dioica; (iii) mapped the occurrence and distribution of host plants and larvae in two arable landscapes in Germany during maize anthesis; and (iv) described the temporal occurrence of a 1-year population of A. urticae. (i) Larvae-fed 200 Bt-maize pollen grains/cm(2) had a reduced feeding activity. Significant differences in developmental time existed at pollen densities of 300 Bt-maize pollen grains/cm(2) and in survival at 400 grains/cm(2). (ii) The highest pollen amount found was 212 grains/cm(2) at the field margin. Mean densities were much lower. (iii) In one region, over 50% of A. urticae nests were located within 5 m of a maize field, while in the other, all nests were found in more than 25 m distance to a maize field. (iv) The percentage of larvae developing during maize anthesis was 19% in the study area. The amount of pollen from maize MON89034 × MON88017 found on host plants is unlikely to adversely affect a significant proportion of larvae of A. urticae. This paper concludes that the risk of event MON89034 × MON88017 to populations of this species is negligible.
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Affiliation(s)
- Mechthild Schuppener
- Department of Plant Physiology, RWTH Aachen University, Worringer Weg 1, D-52074 Aachen, Germany.
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208
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Weak transcription of the cry1Ac gene in nonsporulating Bacillus thuringiensis cells. Appl Environ Microbiol 2012; 78:6466-74. [PMID: 22773626 DOI: 10.1128/aem.01229-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cry1Ac gene of Bacillus thuringiensis subsp. kurstaki HD-73 (B. thuringiensis HD-73) is a typical example of a sporulation-dependent crystal gene and is controlled by sigma E and sigma K during sporulation. To monitor the production and accumulation of Cry1Ac at the cellular level, we developed a green fluorescent protein-based reporter system. The production of Cry1Ac was monitored in spo0A, sigE, and sigK mutants, and these mutants were able to express the Cry1Ac-green fluorescent protein fusion protein. In nonsporulating B. thuringiensis HD-73 cells, low-level expression of cry1Ac was also observed. Reverse transcription-PCR and Western blotting results confirmed that the cry1Ac promoter has low activity in nonsporulating B. thuringiensis cells. A beta-galactosidase assay demonstrated that the transcription of the cry1Ac gene during exponential and transition phases is positively regulated by Spo0A. Additional bioassay results indicated that spo0A and sigE mutants containing the cry1Ac-gfp fusion exhibited insecticidal activity against Plutella xylostella larvae.
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209
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Zhang X, Liu Y, Zhang C, Wang Y, Xu C, Liu X. Rapid isolation of single-chain antibodies from a human synthetic phage display library for detection of Bacillus thuringiensis (Bt) Cry1B toxin. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 81:84-90. [PMID: 22627013 DOI: 10.1016/j.ecoenv.2012.04.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 04/21/2012] [Accepted: 04/21/2012] [Indexed: 06/01/2023]
Abstract
Single chain variable fragment antibody (scFv) is capable of binding its target antigens and is one of the most popular recombinant antibodies format for many applications. In this study, a large human synthetic phage displayed library (Tomlinson J) was employed to generate scFvs against Cry1B toxin by affinity panning. After four rounds of panning, six monoclonal phage particles capable of binding with the Cry1B were isolated, sequenced and characterized by Enzyme-Linked Immunosorbent Assay (ELISA). Two of the identified novel anti-Cry1B scFvs, namely H9 and B12, were expressed in Escherichia coli HB2151 and purified by Ni metal ion affinity chromatography. Sodium dodecyl sulfate polyacrylamine gel electrophoresis (SDS-PAGE) indicated that the relative molecular mass of scFv was estimated at 30 kDa. The purified scFv-H9 was used to develop an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for Cry1B toxin. The linear range of detection for standards in this ic-ELISA was approximately 0.19-1.1 μg mL⁻¹ and 50% inhibition of control (IC₅₀) was 0.84 μg mL⁻¹ for Cry1B. The affinity of scfv-H9 was (1.95±0.12) × 10⁷ M⁻¹ and showed cross-reactivity with Cry1Ab toxin and Cry1Ac toxin (8.53% and 7.58%, respectively), higher cross-reactivity (12.8%) with Cry1C toxin. The average recoveries of Cry1B toxin from spiked leaf and rice samples were in the range 89.5-96.4%, and 88.5-95.6%, respectively, with a coefficient of variation (C.V) less than 6.0%. These results showed promising applications of scfv-H9 for detecting Cry1B toxin in agricultural and environmental samples.
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Affiliation(s)
- Xiao Zhang
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, 210095 Nanjing, PR China
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210
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Dong F, Shi R, Zhang S, Zhan T, Wu G, Shen J, Liu Z. Fusing the vegetative insecticidal protein Vip3Aa7 and the N terminus of Cry9Ca improves toxicity against Plutella xylostella larvae. Appl Microbiol Biotechnol 2012; 96:921-9. [DOI: 10.1007/s00253-012-4213-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 05/24/2012] [Indexed: 10/28/2022]
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211
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Determination of Cry toxin activity and identification of an aminopeptidase N receptor-like gene in Asymmathetes vulcanorum (Coleoptera: Curculionidae). J Invertebr Pathol 2012; 111:94-8. [PMID: 22721915 DOI: 10.1016/j.jip.2012.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/02/2012] [Accepted: 06/11/2012] [Indexed: 11/21/2022]
Abstract
An emergent pest is the weevil Asymmathetes vulcanorum, an insect that attacks Colombian potato areas. Here, some Cry proteins from the entomopathogenic bacteria Bacillus thuringiensis were evaluated as biological control strategy. It was found that Cry1B protoxin caused a mortality of 40% with a dose of 8000 ng/cm(2). Also in this research, it was identified a full length cDNA of an aminopeptidase N, a possible Cry protein receptor located in the insect midgut. This is the first report about B. thuringiensis as an alternative method for control of A. vulcanorum in Colombia.
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212
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Fiuza LM, Schünemann R, Pinto LMN, Zanettini MHB. Two new Brazilian isolates of Bacillus thuringiensis toxic to Anticarsia gemmatalis (Lepidoptera: Noctuidae). BRAZ J BIOL 2012; 72:363-9. [DOI: 10.1590/s1519-69842012000200018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 06/14/2011] [Indexed: 11/22/2022] Open
Abstract
Bacillus thuringiensis is a bacterium used for biopesticides production and pest-resistant plants due to the synthesis of protein crystals by cry genes, which are effective in controlling several insect orders such as Lepidoptera. This work aimed at the evaluation and characterisation of two new B. thuringiensis isolates active against A. gemmatalis (Hübner 1818) larvae, which is the soybean major pest. The results showed that Bt117-4 isolate amplified fragments corresponding to cry2 and cry9 genes, and synthesised protein fragments equivalent to 130, 90 and 45 kDa. The Bt3146-4 isolate amplified DNA fragments corresponding to cry9 gene and synthesised protein fragments of 70, 58 and 38 kDa. Transmission electron microscopy revealed the presence of protein crystals in both isolates. CL50 with Cry purified proteins from Bt117-4 and Bt3146-4, corresponded to 0.195 and 0.191 µg larvae-1, respectively. The two B. thuringiensis isolates selected in this study were effective to control velvetbean caterpillar at laboratory conditions. Field tests should be carried on to develop new biopesticides formulation as well for cry genes resource for Anticarsia gemmatalis resistant transgenic plants.
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Affiliation(s)
| | | | - LMN. Pinto
- Universidade do Vale do Rio dos Sinos, Brazil
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213
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Mc Lean M. A review of the environmental safety of the Cry1Ab protein. ENVIRONMENTAL BIOSAFETY RESEARCH 2012; 10:51-71. [PMID: 22541994 DOI: 10.1051/ebr:2012003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Morven Mc Lean
- Center for Environmental Risk Assessment, ILSI Research Foundation
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214
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215
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216
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Mining new crystal protein genes from Bacillus thuringiensis on the basis of mixed plasmid-enriched genome sequencing and a computational pipeline. Appl Environ Microbiol 2012; 78:4795-801. [PMID: 22544259 DOI: 10.1128/aem.00340-12] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have designed a high-throughput system for the identification of novel crystal protein genes (cry) from Bacillus thuringiensis strains. The system was developed with two goals: (i) to acquire the mixed plasmid-enriched genomic sequence of B. thuringiensis using next-generation sequencing biotechnology, and (ii) to identify cry genes with a computational pipeline (using BtToxin_scanner). In our pipeline method, we employed three different kinds of well-developed prediction methods, BLAST, hidden Markov model (HMM), and support vector machine (SVM), to predict the presence of Cry toxin genes. The pipeline proved to be fast (average speed, 1.02 Mb/min for proteins and open reading frames [ORFs] and 1.80 Mb/min for nucleotide sequences), sensitive (it detected 40% more protein toxin genes than a keyword extraction method using genomic sequences downloaded from GenBank), and highly specific. Twenty-one strains from our laboratory's collection were selected based on their plasmid pattern and/or crystal morphology. The plasmid-enriched genomic DNA was extracted from these strains and mixed for Illumina sequencing. The sequencing data were de novo assembled, and a total of 113 candidate cry sequences were identified using the computational pipeline. Twenty-seven candidate sequences were selected on the basis of their low level of sequence identity to known cry genes, and eight full-length genes were obtained with PCR. Finally, three new cry-type genes (primary ranks) and five cry holotypes, which were designated cry8Ac1, cry7Ha1, cry21Ca1, cry32Fa1, and cry21Da1 by the B. thuringiensis Toxin Nomenclature Committee, were identified. The system described here is both efficient and cost-effective and can greatly accelerate the discovery of novel cry genes.
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217
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Baum JA, Sukuru UR, Penn SR, Meyer SE, Subbarao S, Shi X, Flasinski S, Heck GR, Brown RS, Clark TL. Cotton plants expressing a hemipteran-active Bacillus thuringiensis crystal protein impact the development and survival of Lygus hesperus (Hemiptera: Miridae) nymphs. JOURNAL OF ECONOMIC ENTOMOLOGY 2012; 105:616-624. [PMID: 22606834 DOI: 10.1603/ec11207] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The plant bugs Lygus hesperus Knight (Hemiptera: Miridae) and L. lineolaris (Palisot de Beauvois) have emerged as economic pests of cotton in the United States. These hemipteran species are refractory to the insect control traits found in genetically modified commercial varieties of cotton. In this article, we report the isolation and characterization of a 35 kDa crystal protein from Bacillus thuringiensis, designated TIC807, which causes reduced mass gain and mortality of L. hesperus and L. lineolaris nymphs when presented in an artificial diet feeding assay. Cotton plants expressing the TIC807 protein were observed to impact the survival and development of L. hesperus nymphs in a concentration-dependent manner. These results, demonstrating in planta activity of a Lygus insecticidal protein, represent an important milestone in the development of cotton varieties protected from Lygus feeding damage.
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Affiliation(s)
- James A Baum
- Monsanto Company, 700 Chesterfield Parkway West, Chesterfield, MO 63017, USA.
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218
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Bravo A, Gómez I, Porta H, García-Gómez BI, Rodriguez-Almazan C, Pardo L, Soberón M. Evolution of Bacillus thuringiensis Cry toxins insecticidal activity. Microb Biotechnol 2012; 6:17-26. [PMID: 22463726 PMCID: PMC3815381 DOI: 10.1111/j.1751-7915.2012.00342.x] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Insecticidal Cry proteins produced by Bacillus thuringiensis are use worldwide in transgenic crops for efficient pest control. Among the family of Cry toxins, the three domain Cry family is the better characterized regarding their natural evolution leading to a large number of Cry proteins with similar structure, mode of action but different insect specificity. Also, this group is the better characterized regarding the study of their mode of action and the molecular basis of insect specificity. In this review we discuss how Cry toxins have evolved insect specificity in nature and analyse several cases of improvement of Cry toxin action by genetic engineering, some of these examples are currently used in transgenic crops. We believe that the success in the improvement of insecticidal activity by genetic evolution of Cry toxins will depend on the knowledge of the rate-limiting steps of Cry toxicity in different insect pests, the mapping of the specificity binding regions in the Cry toxins, as well as the improvement of mutagenesis strategies and selection procedures.
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Affiliation(s)
- Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México. Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico
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219
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Boniolo FS, Rodrigues RC, Prata AMR, López ML, Jacinto T, da Silveira MM, Berbert-Molina MA. Oxygen supply in Bacillus thuringiensis fermentations: bringing new insights on their impact on sporulation and δ-endotoxin production. Appl Microbiol Biotechnol 2012; 94:625-36. [DOI: 10.1007/s00253-011-3746-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 11/02/2011] [Accepted: 11/17/2011] [Indexed: 11/28/2022]
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220
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Li H, Shu C, He X, Gao J, Liu R, Huang D. Detection and identification of vegetative insecticidal proteins vip3 genes of Bacillus thuringiensis strains using polymerase chain reaction-high resolution melt analysis. Curr Microbiol 2012; 64:463-8. [PMID: 22350000 DOI: 10.1007/s00284-012-0092-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 01/23/2012] [Indexed: 10/28/2022]
Abstract
In this study, vegetative insecticidal proteins vip3 genes from Bacillus thuringiensis strains were detected based on polymerase chain reaction-high resolution melt (PCR-HRM) analysis. A pair of primers was designed according to the conservative sequences in 150 bp region of the known vip3 subfamily. The 150 bp regions of difference vip3 genes have only a few nucleotide difference vip3 genes were detected in 8 of 11 standard B. thuringiensis strains, and vip3Aa genes, vip3Af genes and vip3Ba gene can be distinguished as different melting curves by this method. The results demonstrate the utility of the HRM assay for mutant screening using vip3 gene. The PCR-HRM method may be a valuable and reliable tool for specific detection and identification of vip3 genes.
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Affiliation(s)
- Haitao Li
- Northeast Agricultural University, Harbin 150030, People's Republic of China.
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221
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Zhang W, Crickmore N, George Z, Xie L, He YQ, Li Y, Tang JL, Tian L, Wang X, Fang X. Characterization of a new highly mosquitocidal isolate of Bacillus thuringiensis – An alternative to Bti? J Invertebr Pathol 2012; 109:217-22. [DOI: 10.1016/j.jip.2011.11.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 10/31/2011] [Accepted: 11/05/2011] [Indexed: 11/26/2022]
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222
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Monnerat R, Martins E, Praça L, Dumas V, Berry C. Activity of a Brazilian strain of Bacillus thuringiensis israelensis against the cotton Boll Weevil Anthonomus grandis Boheman (Coleoptera: Tenebrionidae). NEOTROPICAL ENTOMOLOGY 2012; 41:62-7. [PMID: 23950011 DOI: 10.1007/s13744-011-0008-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 12/01/2011] [Indexed: 05/27/2023]
Abstract
A Brazilian Bacillus thuringiensis subspecies israelensis, toxic to Diptera, including mosquitoes, was found also to show toxicity to the coleopteran boll weevil Anthonomus grandis Boheman at an equivalent level to that of the standard coleopteran-active B. thuringiensis subspecies tenebrionis T08017. Recombinant B. thuringiensis strains expressing the individual Cyt1Aa, Cry4Aa, Cry4Ba and Cry11Aa toxins from this strain were assessed to evaluate their potential contribution to the activity against A. grandis, either alone or in combination. Whilst individual toxins produced mortality, none was sufficiently potent to allow calculation of LC50 values. Combinations of toxins were unable to attain the same potency as the parental B. thuringiensis subsp. israelensis, suggesting a major role for other factors produced by this strain.
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Affiliation(s)
- R Monnerat
- EMBRAPA Recursos Genéticos e Biotecnologia, Brasília, DF, Brasil.
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223
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Asokan R, Swamy HMM, Arora DK. Screening, diversity and partial sequence comparison of vegetative insecticidal protein (vip3A) genes in the local isolates of Bacillus thuringiensis Berliner. Curr Microbiol 2012; 64:365-70. [PMID: 22246044 DOI: 10.1007/s00284-011-0078-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 12/22/2011] [Indexed: 10/14/2022]
Abstract
Characterization, direct sequencing of the PCR amplicon and phylogenetic relationship was done to discover a novel Vip protein genes of the Bt isolates, to improve the prospects for insect control, more Vip proteins should be sought out and researched to predict their insecticidal activity. Characterization was based on direct sequencing of PCR amplicon using primers specific to vip3A gene was presented here. 12 out of 18 isolates screened were positive for vip gene-specific primers. Homology search for the partial sequences using BLAST showed that 11 isolates had high similarity to vip3Aa gene and only one fragment with vip3Ae gene (25-100% at nucleotide and amino acid level). Phylogenetic analysis showed that the gene sequences were responsible for geographic separation for divergence within vip genes, consistent with the evaluation of distinct bacterial population. Despite the geographical distances, strains harbouring vip genes have originated from common ancestors may significantly contribute to control resistant insect pests. Some strains have evolved to be quite distinct and others remain as members of closely related groups. The reported method is a powerful tool to find novel Vip3A proteins from large-scale Bt strains which is effective in terms of time and cost. Further the Vip proteins produced by different strains of B. thuringiensis are unique in terms of the sequence divergence and hence may also differ in their insecticidal activities.
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Affiliation(s)
- R Asokan
- Bio Pesticide Laboratory, Division of Biotechnology, Indian Institute of Horticultural Research, Hessarghatta Lake Post, Bangalore 560 089, Karnataka, India.
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Co-expression and Synergism Analysis of Vip3Aa29 and Cyt2Aa3 Insecticidal Proteins from Bacillus thuringiensis. Curr Microbiol 2012; 64:326-31. [DOI: 10.1007/s00284-011-0070-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 12/05/2011] [Indexed: 10/14/2022]
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225
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Mosquito larvicidal and pupicidal efficacy of Solanum xanthocarpum (Family: Solanaceae) leaf extract and bacterial insecticide, Bacillus thuringiensis, against Culex quinquefasciatus Say (Diptera: Culicidae). Parasitol Res 2012; 110:2541-50. [DOI: 10.1007/s00436-011-2797-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Accepted: 12/15/2011] [Indexed: 11/25/2022]
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226
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Li H, Bouwer G. Toxicity of Bacillus thuringiensis Cry proteins to Helicoverpa armigera (Lepidoptera: Noctuidae) in South Africa. J Invertebr Pathol 2012; 109:110-6. [DOI: 10.1016/j.jip.2011.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 10/08/2011] [Accepted: 10/10/2011] [Indexed: 11/30/2022]
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227
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Paris M, Melodelima C, Coissac E, Tetreau G, Reynaud S, David JP, Despres L. Transcription profiling of resistance to Bti toxins in the mosquito Aedes aegypti using next-generation sequencing. J Invertebr Pathol 2011; 109:201-8. [PMID: 22115744 DOI: 10.1016/j.jip.2011.11.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/04/2011] [Accepted: 11/05/2011] [Indexed: 01/15/2023]
Abstract
The control of mosquitoes transmitting infectious diseases relies mainly on the use of chemical insecticides. However, resistance to most chemical insecticides threatens mosquito control programs. In this context, the spraying of toxins produced by the bacteria Bacillus thuringiensis subsp. israelensis (Bti) in larval habitats represents an alternative to chemical insecticides and is now widely used for mosquito control. Recent studies suggest that resistance of mosquitoes to Bti toxin may occur locally but mechanisms have not been characterized so far. In the present study, we investigated gene transcription level variations associated with Bti toxin resistance in the mosquito Aedes aegypti using a next-generation sequencing approach. More than 6 million short cDNA tags were sequenced from larvae of two strains sharing the same genetic background: a Bti toxins-resistant strain and a susceptible strain. These cDNA tags were mapped with a high coverage (308 reads per position in average) to more than 6000 genes of Ae. aegypti genome and used to quantify and compare the transcription level of these genes between the two mosquito strains. Among them, 86 genes were significantly differentially transcribed more than 4-fold in the Bti toxins resistant strain comparatively to the susceptible strain. These included gene families previously associated with Bti toxins resistance such as serine proteases, alkaline phosphatase and alpha-amylase. These results are discussed in regards of potential Bti toxins resistance mechanisms in mosquitoes.
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Affiliation(s)
- Margot Paris
- Laboratoire d'Ecologie Alpine, UMR 5553 CNRS-Université de Grenoble, France
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228
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Ibrahim MA, Griko N, Junker M, Bulla LA. Bacillus thuringiensis: a genomics and proteomics perspective. Bioeng Bugs 2011; 1:31-50. [PMID: 21327125 DOI: 10.4161/bbug.1.1.10519] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 11/04/2009] [Accepted: 11/04/2009] [Indexed: 02/03/2023] Open
Abstract
Bacillus thuringiensis (Bt) is a unique bacterium in that it shares a common place with a number of chemical compounds which are used commercially to control insects important to agriculture and public health. Although other bacteria, including B. popilliae and B. sphaericus, are used as microbial insecticides, their spectrum of insecticidal activity is quite limited compared to Bt. Importantly, Bt is safe for humans and is the most widely used environmentally compatible biopesticide worldwide. Furthermore, insecticidal Bt genes have been incorporated into several major crops, rendering them insect resistant, and thus providing a model for genetic engineering in agriculture.This review highlights what the authors consider the most relevant issues and topics pertaining to the genomics and proteomics of Bt. At least one of the authors (L.A.B.) has spent most of his professional life studying different aspects of this bacterium with the goal in mind of determining the mechanism(s) by which it kills insects. The other authors have a much shorter experience with Bt but their intellect and personal insight have greatly enriched our understanding of what makes Bt distinctive in the microbial world. Obviously, there is personal interest and bias reflected in this article notwithstanding oversight of a number of published studies. This review contains some material not published elsewhere although several ideas and concepts were developed from a broad base of scientific literature up to 2010.
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229
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McNeil BC, Dean DH. Bacillus thuringiensis Cry2Ab is active on Anopheles mosquitoes: single D block exchanges reveal critical residues involved in activity. FEMS Microbiol Lett 2011; 325:16-21. [PMID: 22092857 DOI: 10.1111/j.1574-6968.2011.02403.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 08/18/2011] [Accepted: 08/26/2011] [Indexed: 01/19/2023] Open
Abstract
Cry2Aa exhibits dual activity to Lepidoptera and Diptera. Cry2Ab differs in amino acid sequence from Cry2Aa by 13% and has shown significant lepidopteran activity, but no mosquitocidal activity. Previous studies implicate 23 Cry2Aa specificity-conferring residues of domain II, which differ in Cry2Ab. Nine residues are putatively involved in conferring Cry2Aa dipteran specificity. To explore Cry2Ab dipteran toxicity, site-directed mutagenesis was employed to exchange Cry2Ab residues with Cry2Aa D (dipteran) block residues. Cry2Ab wild type demonstrated high toxicity (LC(50) of 540 ng mL(-1)) to Anopheles gambiae, but not to Aedes or Culex, within a 24-h time period. Cry2Ab should be reclassified as a dual active Cry toxin. Cry2Ab mutagenesis revealed critical residues for Cry2Ab protein function, as well as enhanced activity against the malarial mosquito, An. gambiae.
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Affiliation(s)
- Betina C McNeil
- Department of Biochemistry, The Ohio State University, Columbus, OH 43212, USA
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230
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Peng D, Wang F, Li N, Zhang Z, Song R, Zhu Z, Ruan L, Sun M. Single cysteine substitution in Bacillus thuringiensis Cry7Ba1 improves the crystal solubility and produces toxicity to Plutella xylostella larvae. Environ Microbiol 2011; 13:2820-31. [DOI: 10.1111/j.1462-2920.2011.02557.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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231
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Naimov S, Valkova R, Dukiandjiev S, Minkov I, de Maagd RA. Carboxy-terminal extension effects on crystal formation and insecticidal properties of Cry15Aa. J Invertebr Pathol 2011; 108:56-8. [DOI: 10.1016/j.jip.2011.05.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/19/2011] [Accepted: 05/19/2011] [Indexed: 11/29/2022]
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232
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Paris M, David JP, Despres L. Fitness costs of resistance to Bti toxins in the dengue vector Aedes aegypti. ECOTOXICOLOGY (LONDON, ENGLAND) 2011; 20:1184-1194. [PMID: 21461926 DOI: 10.1007/s10646-011-0663-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/19/2011] [Indexed: 05/30/2023]
Abstract
Sustainable insect vector disease control strategies involve delaying the evolution of resistance to insecticides in natural populations. The evolutionary dynamics of resistance in the field is highly dependent on the fitness cost of resistance alleles. To successfully manage resistance evolution in target species, it is not only important to find evidence of fitness cost in resistant insects, but also to determine at which stage of the insect's life it is expressed. Here, we show that resistance costs to the bacterio-insecticide Bacillus thuringiensis subsp. israelensis (Bti) are expressed at all the life-stages of the dengue vector Aedes aegypti, including egg survival, larval development time, and female fecundity. We show that the storage of eggs for 4 months is long enough to counter-select resistance alleles. This suggests that Bti resistance is not likely to evolve in temperate climates where most mosquito species overwinter as eggs. In tropical regions with a rapid turn-over of generations, resistance alleles are likely to be counter-selected in only few generations without treatment through fitness costs expressed in terms of larval development time and female fecundity. We discuss the implications of our findings in terms of sustainable management strategies in light of the challenge of preserving the long-term efficiency of this environmentally safe anti-mosquito bio-insecticide.
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Affiliation(s)
- Margot Paris
- Laboratoire d'Ecologie Alpine, UMR CNRS 5553, Université Joseph Fourier, BP 53, 38041, Grenoble Cedex 09, France.
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233
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Aboussaid H, Vidal-Quist JC, Oufdou K, El Messoussi S, Castañera P, González-Cabrera J. Occurrence, characterization and insecticidal activity of Bacillus thuringiensis strains isolated from argan fields in Morocco. ENVIRONMENTAL TECHNOLOGY 2011; 32:1383-1391. [PMID: 21970180 DOI: 10.1080/09593330.2010.536789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Soils collected from five locations in the argan forest (an endemic plant) in Morocco were used to form the first collection of Bacillus thuringiensis (Bt) strains from this area (58 strains). Here we found that the argan forest is a major source of Bt, as 90.62% of the samples contained Bt strains. These strains produced mainly spherical or irregular crystals that in some cases remained adhered to the spore after cell lysis. There was no strain producing bipyramidal crystals, suggesting the absence of strains bearing crv1 genes. This was confirmed by PCR analysis using eight primer pairs that can potentially detect 13 different groups of cry and cyt genes. Strains containing cry7/8 were the most abundant (25.53%), followed by strains harbouring cry9A (14.89%), cry11 (8.51%) and cry4 (4.25%). The mixtures of spores and crystals as well as culture supernatants were assayed for toxicity towards Ceratitis capitata (Medfly), showing up to 30% mortality. Our findings suggest that the argan region is a suitable target for future and wider screening programmes looking for strains bearing toxins or combinations of them to develop more efficient Bt-based formulates.
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Affiliation(s)
- H Aboussaid
- Laboratory of Biology and Biotechnology of Microorganisms, Cadi Ayyad University, Faculty of Sciences-Semlalia, Marrakesh, Morocco
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234
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Guo S, Zhang C, Lin X, Zhang Y, He K, Song F, Zhang J. Purification of an active fragment of Cry1Ie toxin from Bacillus thuringiensis. Protein Expr Purif 2011; 78:204-8. [DOI: 10.1016/j.pep.2011.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 03/06/2011] [Accepted: 03/07/2011] [Indexed: 10/18/2022]
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235
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Dhurua S, Gujar GT. Field-evolved resistance to Bt toxin Cry1Ac in the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), from India. PEST MANAGEMENT SCIENCE 2011; 67:898-903. [PMID: 21438121 DOI: 10.1002/ps.2127] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 10/12/2010] [Accepted: 12/23/2010] [Indexed: 05/25/2023]
Abstract
BACKGROUND The pink bollworm is one of the most destructive pests of cotton. Transgenic cotton producing Bt toxin Cry1Ac or a combination of Cry1Ac and Cry2Ab2 has been used effectively against this pest. However, some other insects have evolved resistance to Bt toxins in the field. During the 2007-2008 and 2008-2009 seasons, pink bollworm populations in India were surveyed to evaluate their responses to Cry1Ac and seed powder containing Cry1Ac and Cry2Ab2. RESULTS The results provide evidence that resistance to Cry1Ac had evolved by 2008 in a population sampled from non-Bt cotton in the Amreli district of Gujarat in western India. The median lethal concentration of Cry1Ac for five-day-old larvae (LC50 ) was significantly higher for insects derived in 2008 from Amreli than for any of the other field populations tested from four locations in India. For Cry1Ac, the mean LC50 for the strain derived from Amreli in 2008 was 44 times higher than for the most susceptible population. However, for seed powder of Bollgard II containing primarily Cry2Ab2, the 2008 Amreli population was only slightly less susceptible than the most susceptible population. CONCLUSIONS The data reported here constitute the first evidence of field-evolved resistance of pink bollworm to Cry1Ac. This initial evidence spurred more extensive evaluations during the 2009-2010 growing season, which confirmed field-evolved resistance to Cry1Ac in Amreli. The lack of cross-resistance to Cry2Ab2 suggests that plants producing this toxin are likely to be more effective against resistant populations than plants producing only Cry1Ac.
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Affiliation(s)
- Sanyasi Dhurua
- Division of Entomology, Indian Agricultural Research Institute, New Delhi, India
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236
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Melnikov O, Baranes N, Einav M, Ben-Dov E, Manasherob R, Itsko M, Zaritsky A. Tandem repeats in a new toxin gene from Bacillus thuringiensis and in other cry11-like genes. J Mol Microbiol Biotechnol 2011; 20:204-10. [PMID: 21778765 DOI: 10.1159/000329824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A new gene, cry11Bb2 from a field isolate of Bacillus thuringiensis, was cloned for expression in Escherichia coli. The encoded protein, with a deduced molecular mass of 89.5 kDa, exhibits 97 and 79% identities with the overlap regions of Cry11Bb1 from B. thuringiensis ssp. medellin and Cry11Ba1 from ssp. jegathesan, respectively. It is however longer than Cry11Bb1 by 42 amino acids in its carboxy-terminus, of which 32 comprise 2 tandem repeats additional to the 5 existing in the latter polypeptide. Possible roles for this recurrent motif among Cry toxins and their accessory proteins, and for their encoding genes are proposed.
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Affiliation(s)
- Olga Melnikov
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
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237
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Chenniappan K, Ayyadurai N. Synergistic activity of Cyt1A from Bacillus thuringiensis subsp. israelensis with Bacillus sphaericus B101 H5a5b against Bacillus sphaericus B101 H5a5b-resistant strains of Anopheles stephensi Liston (Diptera: Culicidae). Parasitol Res 2011; 110:381-8. [DOI: 10.1007/s00436-011-2502-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 06/21/2011] [Indexed: 10/18/2022]
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238
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Vieira PDDS, Motta CMDS, Lima D, Torres JB, Quecine MC, Azevedo JL, Oliveira NTD. Endophytic fungi associated with transgenic and non-transgenic cotton. Mycology 2011. [DOI: 10.1080/21501203.2011.584390] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
| | | | - Débora Lima
- a Department of Mycology , Federal University of Pernambuco (UFPE) , Recife, Brazil
| | - Jorge Braz Torres
- b Departament of Agronomy , Federal Rural University of Pernambuco (UFRPE) , Recife, Brazil
| | - Maria Carolina Quecine
- c Departament of Genetics, Escola Superior de Agricultura “Luiz de Queiroz” , University of São Paulo , Piracicaba, Brazil
| | - João Lúcio Azevedo
- c Departament of Genetics, Escola Superior de Agricultura “Luiz de Queiroz” , University of São Paulo , Piracicaba, Brazil
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239
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Bulushova NV, Elpidina EN, Zhuzhikov DP, Lyutikova LI, Ortego F, Kirillova NE, Zalunin IA, Chestukhina GG. Complex of digestive proteinases of Galleria mellonella caterpillars. Composition, properties, and limited proteolysis of Bacillus thuringiensis endotoxins. BIOCHEMISTRY (MOSCOW) 2011; 76:581-9. [DOI: 10.1134/s0006297911050087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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240
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Oppert B, Morgan TD, Kramer KJ. Efficacy of Bacillus thuringiensis Cry3Aa protoxin and protease inhibitors against coleopteran storage pests. PEST MANAGEMENT SCIENCE 2011; 67:568-573. [PMID: 21268232 DOI: 10.1002/ps.2099] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 10/20/2010] [Accepted: 10/26/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND Environmental impacts and resistance to insecticides pose serious challenges to stored-product insect and other types of pest control. Insect-resistant transgenic grain is a potential alternative to fumigants, but candidate control proteins are needed, especially for coleopterans. Therefore, we evaluated the efficacy of a coleopteran-active toxin, Bacillus thuringiensis Cry3Aa, with or without protease inhibitors, in laboratory feeding assays against coleopteran storage pests. RESULTS In a comparison of the toxicity of Cry3Aa protoxin towards three species of coleopteran storage pests, Tenebrio molitor L. was found to be most sensitive, Tribolium castaneum (Herbst.) was most refractory and Rhyzopertha dominica F. displayed an intermediate response. For R. dominica, Cry3Aa combined with 3500 mg potato carboxypeptidase inhibitor or 5000 mg aprotinin kg(-1) diet resulted in both delayed development and increased mortality. Potato carboxypeptidase inhibitor and bovine aprotinin reduced the LC(50) of Cry3Aa for R. dominica two- and threefold respectively. Cry3Aa treatment resulted in fewer progeny from R. dominica, and progeny was further reduced when the protoxin was combined with potato carboxypeptidase inhibitor. CONCLUSIONS These data support the hypothesis that a combination of Cry3Aa protoxin and protease inhibitors, particularly a potato carboxypeptidase inhibitor, may have applications in control strategies for preventing damage to stored products and grains by coleopteran pests.
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Affiliation(s)
- Brenda Oppert
- USDA Agricultural Research Service, Center for Grain and Animal Health Research, Manhattan, KS 66502, USA.
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241
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Nadarasah G, Stavrinides J. Insects as alternative hosts for phytopathogenic bacteria. FEMS Microbiol Rev 2011; 35:555-75. [DOI: 10.1111/j.1574-6976.2011.00264.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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242
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Determination of insecticidal Cry1Ab protein in soil collected in the final growing seasons of a nine-year field trial of Bt-maize MON810. Transgenic Res 2011; 21:77-88. [DOI: 10.1007/s11248-011-9509-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 03/27/2011] [Indexed: 10/18/2022]
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243
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Sanahuja G, Banakar R, Twyman RM, Capell T, Christou P. Bacillus thuringiensis: a century of research, development and commercial applications. PLANT BIOTECHNOLOGY JOURNAL 2011; 9:283-300. [PMID: 21375687 DOI: 10.1111/j.1467-7652.2011.00595.x] [Citation(s) in RCA: 397] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Bacillus thuringiensis (Bt) is a soil bacterium that forms spores during the stationary phase of its growth cycle. The spores contain crystals, predominantly comprising one or more Cry and/or Cyt proteins (also known as δ-endotoxins) that have potent and specific insecticidal activity. Different strains of Bt produce different types of toxin, each of which affects a narrow taxonomic group of insects. Therefore, Bt toxins have been used as topical pesticides to protect crops, and more recently the proteins have been expressed in transgenic plants to confer inherent pest resistance. Bt transgenic crops have been overwhelmingly successful and beneficial, leading to higher yields and reducing the use of chemical pesticides and fossil fuels. However, their deployment has attracted some criticism particularly with regard to the potential evolution of pest-resistant insect strains. Here, we review recent progress in the development of Bt technology and the countermeasures that have been introduced to prevent the evolution of resistant insect populations.
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Affiliation(s)
- Georgina Sanahuja
- Department of Plant Production and Forestry Science, ETSEA, University of Lleida, Lleida, Spain
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244
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Dinon AZ, Prins TW, van Dijk JP, Arisi ACM, Scholtens IMJ, Kok EJ. Development and validation of real-time PCR screening methods for detection of cry1A.105 and cry2Ab2 genes in genetically modified organisms. Anal Bioanal Chem 2011; 400:1433-42. [PMID: 21445662 PMCID: PMC3081059 DOI: 10.1007/s00216-011-4875-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 03/04/2011] [Accepted: 03/06/2011] [Indexed: 11/28/2022]
Abstract
Primers and probes were developed for the element-specific detection of cry1A.105 and cry2Ab2 genes, based on their DNA sequence as present in GM maize MON89034. Cry genes are present in many genetically modified (GM) plants and they are important targets for developing GMO element-specific detection methods. Element-specific methods can be of use to screen for the presence of GMOs in food and feed supply chains. Moreover, a combination of GMO elements may indicate the potential presence of unapproved GMOs (UGMs). Primer-probe combinations were evaluated in terms of specificity, efficiency and limit of detection. Except for specificity, the complete experiment was performed in 9 PCR runs, on 9 different days and by testing 8 DNA concentrations. The results showed a high specificity and efficiency for cry1A.105 and cry2Ab2 detection. The limit of detection was between 0.05 and 0.01 ng DNA per PCR reaction for both assays. These data confirm the applicability of these new primer-probe combinations for element detection that can contribute to the screening for GM and UGM crops in food and feed samples.
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Affiliation(s)
- Andréia Z Dinon
- Department of Food Science and Technology, Federal University of Santa Catarina, Rod. Admar Gonzaga, 1346, Florianópolis, SC 880034-001, Brazil
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245
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Dechklar M, Tiewsiri K, Angsuthanasombat C, Pootanakit K. Functional expression in insect cells of glycosylphosphatidylinositol-linked alkaline phosphatase from Aedes aegypti larval midgut: a Bacillus thuringiensis Cry4Ba toxin receptor. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:159-166. [PMID: 21146607 DOI: 10.1016/j.ibmb.2010.11.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 11/18/2010] [Accepted: 11/29/2010] [Indexed: 05/30/2023]
Abstract
Bacillus thuringiensis produces insecticidal crystal (Cry) proteins which bind to cell surface receptors on the brush border membrane of susceptible midgut larvae. The toxin-receptor interaction generates pores in midgut epithelial cells resulting in cell lysis. Here, a cDNA encoding membrane-bound alkaline phosphatase from Aedes aegypti (Aa-mALP) midgut larvae, based on the sequence identity hit to Bombyx mori membrane-bound ALP, was amplified by RT-PCR and transiently expressed in Spodoptera frugiperda (Sf9) insect cells as a 58-kDa membrane-bound protein via the baculovirus expression system and confirmed by digestion with phosphatidylinositol-specific phospholipase C and LC-MS/MS analysis. Immunolocalization results showed that Cry4Ba is able to bind to only Sf9 cells-expressing Aa-mALP. Moreover, these cells were shown to undergo cell lysis in the presence of 100 μg/ml trypsin-treated toxin. Finally, trypan blue exclusion assay also demonstrated an increase in cell death in recombinant cells treated with Cry4Ba. Overall results indicated that Aa-mALP protein was responsible for mediating Cry4Ba toxicity against Sf9 cells, suggesting its role as a receptor for Cry4Ba toxin in A. aegypti mosquito larvae.
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Affiliation(s)
- Manasave Dechklar
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
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Mahalakshmi A, Shenbagarathai R. Homology modeling of Cry10Aa toxin from B. thuringiensis israelensis and B. thuringiensis subsp. LDC-9. J Biomol Struct Dyn 2011; 28:363-78. [PMID: 20919752 DOI: 10.1080/07391102.2010.10507366] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
A three dimensional model was developed for Cry10Aa protein sequence of B. thuringiensis LDC-9 and B. thuringiensis israelensis that has not been solved empirically by X-ray crystallography or NMR. Homology modeling was employed for the structure prediction using Cry2Aa as template protein, a high-resolution X-ray crystallography structure. The model predicted for the B. thuringiensis LDC-9 Cry10Aa protein reveals a partial N-terminal domain only due to its partial sequence of 104 amino acids. B. thuringiensis israelensis Cry10Aa model contains three domains such as domain I, a bundle of eight alpha helices with the central relatively hydrophobic helix surrounded by amphipathic helices while domain II and III contain mostly beta-sheets. Significant structural differences within domain II in this model among all Cry protein structures indicates that it is involved in recognition and binding to cell surfaces. Comparison of B. thuringiensis israelensis predicted structure with available experimentally determined Cry structures reveals identical folds. The distribution of electrostatic potential on the surface of the molecules in the model is non-uniform and identifies one side of the alpha-helical domain as negatively charged indicating orientation of toxic molecules toward the cell membrane during the initial binding with a cell surface receptor. The collective knowledge of Cry toxin structures will lead to a more critical understanding of the structural basis for receptor binding and pore formation, as well as allowing the scope of diversity to be better appreciated. This model will serve as a starting point for the design of mutagenesis experiments aimed to improve the toxicity and to provide a new tool for the elucidation of the mechanism of action of these mosquitocidal proteins.
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Affiliation(s)
- A Mahalakshmi
- PG and Research Department of Zoology and Biotechnology, Lady Doak College, Madurai-625 002, TamilNadu, India.
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Paris M, Tetreau G, Laurent F, Lelu M, Despres L, David JP. Persistence of Bacillus thuringiensis israelensis (Bti) in the environment induces resistance to multiple Bti toxins in mosquitoes. PEST MANAGEMENT SCIENCE 2011; 67:122-128. [PMID: 21162152 DOI: 10.1002/ps.2046] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 04/28/2010] [Accepted: 07/20/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND The simultaneous production of six different toxins by Bacillus thuringiensis israelensis (Bti) is thought to delay the evolution of resistance in treated mosquito populations. Recent studies have shown that Bti can persist and proliferate in the environment, thereby imposing continuous selective pressure on mosquito populations, raising concerns about the long-term effectiveness of this bioinsecticide. In order to evaluate the effect of Bti persistence on the evolution of resistance, the authors selected a laboratory Aedes aegypti L. strain with field-collected leaf litter containing Bti toxins. RESULTS It is shown that resistance to each individual Bti toxin (up to 30-fold) can be obtained after only a few generations of selection. However, the resistance to commercial Bti and to environmental Bti remains low (twofold and 3.4-fold respectively) in the selected strain. Furthermore, some selected individuals exhibited resistance to Cry4B but not to Cry4A, suggesting that two distinct resistance mechanisms are involved in the resistance to these two toxins. CONCLUSION Considering that resistance to Cry toxins might act as a first step to resistance to a complete Bti toxin mixture, the present results highlight the importance of testing each toxin individually in order accurately to monitor Bti toxin resistance evolution in field populations.
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Affiliation(s)
- Margot Paris
- Laboratoire d'Ecologie Alpine, UMR 5553 CNRS-Université de Grenoble, Grenoble, France
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Anitha D, Kumar NS, Vijayan D, Ajithkumar K, Gurusubramanian G. Characterization of Bacillus thuringiensis isolates and their differential toxicity against Helicoverpa armigera populations. J Basic Microbiol 2010; 51:107-14. [PMID: 21077117 DOI: 10.1002/jobm.201000141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 06/21/2010] [Indexed: 11/09/2022]
Abstract
Bacillus thuringiensis isolates were characterized in rhizospheric cotton soils by using acetate selection process from eight different locations in South India. The fact that B. thuringiensis indices were higher in proportion in soil samples taken from Tamil Nadu and Karnataka than from Andhra Pradesh, indicates the abundance of B. thuringiensis populations in the cotton rhizosphere. Biochemical typing of the isolates designated eight local isolates (BtNg13, BtCo1, BtHyb7, BtAm2, BtRm5, BtWr3, BtPl 4, BtN 9), which belong to subspecies kurstaki, the most prevalent subspecies. Toxicity assays on American boll worm larval (F(1) ) populations collected from the Andhra Pradesh, Bangalore and Coimbatore regions, with a susceptible insect strain against different isolates of B. thuringiensis kurstaki spore-crystal mix, revealed distinct susceptibility patterns and specificity. The highest susceptibility was observed in the F(1) populations of Coimbatore, followed by Bangalore and Hyderabad populations, in comparison with the susceptible insect strain. Significant differences were observed (p < 0.0005 and CD = 5.3975) among Btk local isolates, H. armigera biotypes, Btk spore-crystal mix concentration and their interactions, through the Multifactorial ANOVA analysis. The toxicity of local B. thuringiensis isolates was higher than that of HD-1 (reference B.t.k strain). Indigenous Btk isolates have an enormous potential for the management of H. armigera in terms of development of resistance to HD-1. The present study would serve as a baseline data for future resistance monitoring of B. thuringiensis strains in H. armigera in Southern India.
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Affiliation(s)
- Deepak Anitha
- Centre for Environmental Risk Assessment and Remediation CERAR, University of South Australia, Mawson Lakes campus, Mawson Lakes, South Australia
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Kirillova NE, Levitin EI, Voytsekhovskaya YA, Yudina TG, Zalunin IA, Chestukhina GG. Recombinant Cry9A is able to form crystals in sporulating cells of Bacillus thuringiensis. APPL BIOCHEM MICRO+ 2010. [DOI: 10.1134/s0003683810090048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gobatto V, Giani SG, Camassola M, Dillon AJP, Specht A, Barros NM. Bacillus thuringiensis isolates entomopathogenic for Culex quinquefasciatus (Diptera: Culicidae) and Anticarsia gemmatalis (Lepidoptera: Noctuidae). BRAZ J BIOL 2010; 70:1039-46. [DOI: 10.1590/s1519-69842010000500018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 06/29/2009] [Indexed: 11/22/2022] Open
Abstract
Samples of the Bacillus thuringiensis (Bt) were collected from soil and insects. Eight isolates were selected from rural soil, 15 from urban soil and 11 from insects. These were evaluated for entomopathogenicity against larvae of Anticarsia gemmatalis and Culex quinquefasciatus. The pathogenicity tests showed that a higher percentage of isolates were active against A. gemmatalis (60%) compared to C. quinquefasciatus (31%). Probit analysis (LC50) indicated that against A. gemmatalis four of the isolates presented values similar to the reference strain against A. gemmatalis, while against C. quinquefasciatus one isolate showed an LC50 similar to the reference strain (IPS-82). SDS-PAGE characterisation of two isolates showed a 27 kDa protein fraction related to the Bt subspecies israelensis cytolytic toxin (cyt) gene. One 130 kDa protein, possibly related to the Bt crystal inclusions (cry1) gene, was identified in the other two isolates, which were more toxic for lepidoptera; another isolate presented a protein of 100 kDa. Some new local Bt isolates had similar LC50 probit values to the reference strains.
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Affiliation(s)
| | - SG. Giani
- Universidade de Caxias do Sul, Brazil
| | | | | | - A. Specht
- Universidade de Caxias do Sul, Brazil; Universidade de Caxias do Sul, Brazil
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