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He X, Yang Y, Soberón M, Bravo A, Zhang L, Zhang J, Wang Z. Bacillus thuringiensis Cry9Aa Insecticidal Protein Domain I Helices α3 and α4 Are Two Core Regions Involved in Oligomerization and Toxicity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:1321-1329. [PMID: 38175929 DOI: 10.1021/acs.jafc.3c08070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Bacillus thuringiensis Cry9 proteins show high insecticidal activity against different lepidopteran pests. Cry9 could be a valuable alternative to Cry1 proteins because it showed a synergistic effect with no cross-resistance. However, the pore-formation region of the Cry9 proteins is still unclear. In this study, nine mutations of certain Cry9Aa helices α3 and α4 residues resulted in a complete loss of insecticidal activity against the rice pest Chilo suppressalis; however, the protein stability and receptor binding ability of these mutants were not affected. Among these mutants, Cry9Aa-D121R, Cry9Aa-D125R, Cry9Aa-D163R, Cry9Aa-E165R, and Cry9Aa-D167R are unable to form oligomers in vitro, while the oligomers formed by Cry9Aa-R156D, Cry9Aa-R158D, and Cry9Aa-R160D are unstable and failed to insert into the membrane. These data confirmed that helices α3 and α4 of Cry9Aa are involved in oligomerization, membrane insertion, and toxicity. The knowledge of Cry9 pore-forming action may promote its application as an alternative to Cry1 insecticidal proteins.
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Affiliation(s)
- Xiang He
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei, Anhui Province 230036, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yanchao Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Apdo. Postal 510-3, Morelos 62250, Mexico
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Apdo. Postal 510-3, Morelos 62250, Mexico
| | - Lihong Zhang
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei, Anhui Province 230036, China
| | - Jie Zhang
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei, Anhui Province 230036, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Zeyu Wang
- 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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Hemthanon T, Promdonkoy B, Boonserm P. Screening and characterization of Bacillus thuringiensis isolates for high production of Vip3A and Cry proteins and high thermostability to control Spodoptera spp. J Invertebr Pathol 2023; 201:108020. [PMID: 37956858 DOI: 10.1016/j.jip.2023.108020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/04/2023] [Accepted: 11/10/2023] [Indexed: 11/15/2023]
Abstract
Bacillus thuringiensis (Bt) is an entomopathogenic bacterium that produces crystalline (Cry and Cyt) and soluble (vegetative insecticidal proteins or Vips) proteins during the sporulation and vegetative growth phases, respectively. Combining Cry and Vip proteins could delay insect resistance development and exhibit synergistic activity against various insect pests. This study aims to screen Bt isolates collected from Thailand for high Vip3A and Cry protein production levels and high thermostability to control Spodoptera spp. Among the selected Bt isolates with high target protein synthesis, Bt isolate 506 was found to be safe for further biopesticide formulation due to the absence of non-specific metabolite, as determined by the detection of thermo-stable β-exotoxin I based on biological assays and PCR analysis. Bt isolate 506 showed the presence of Cry1A, Cry2A, and Vip3A-type proteins identified as Cry1Aa45, Cry2Aa22, and Vip3A87, respectively. The insecticidal activity of whole culture extracts containing Vip3A and Cry mixtures and culture supernatants containing secreted Vip3A protein was evaluated against the second-instar larvae of S. exigua and S. frugiperda. The Bt isolate 506 showed high toxicity against both insects, and the insecticidal proteins produced by this isolate retained their activity after heating at 50 °C. This Bt isolate is a promising candidate for further development as a biopesticide against lepidopteran pests.
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Affiliation(s)
- Tharathip Hemthanon
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand
| | - Boonhiang Promdonkoy
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Phahonyothin Road, Khlong Luang, Pathumthani 12120, Thailand
| | - Panadda Boonserm
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand.
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Engineered chimeric insecticidal crystalline protein improves resistance to lepidopteran insects in rice (Oryza sativa L.) and maize (Zea mays L.). Sci Rep 2022; 12:12529. [PMID: 35869123 PMCID: PMC9307649 DOI: 10.1038/s41598-022-16426-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 07/11/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractThe insecticidal crystalline proteins (Crys) are a family of insect endotoxin functioning in crop protection. As insects keep evolving into tolerance to the existing Crys, it is necessary to discover new Cry proteins to overcome potential threatens. Crys possess three functional domains at their N-termini, and the most active region throughout evolution was found at the domain-III. We swapped domain-IIIs from various Cry proteins and generated seven chimeric proteins. All recombinants were expressed in Escherichia coli and their toxicity was assessed by dietary exposure assays. Three of the seven Crys exhibited a high toxicity to Asian corn borer over the controls. One of them, Cry1Ab-Gc, a chimeric Cry1Ab being replaced with the domain-III of Cry1Gc, showed the highest toxicity to rice stem borer when it was over-expressed in Oryza sativa. Furthermore, it was also transformed into maize, backcrossed into commercial maize inbred lines and then produced hybrid to evaluate their commercial value. Transgenic maize performed significant resistance to the Asian corn borer without affecting the yield. We further showed that this new protein did not have adverse effects on the environment. Our results indicated that domain III swapped of Crys could be used as an efficient method for developing new engineered insecticidal protein.
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Unzue A, Caballero CJ, Villanueva M, Fernández AB, Caballero P. Multifunctional Properties of a Bacillus thuringiensis Strain (BST-122): Beyond the Parasporal Crystal. Toxins (Basel) 2022; 14:toxins14110768. [PMID: 36356018 PMCID: PMC9695252 DOI: 10.3390/toxins14110768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
Chemical products still represent the most common form of controlling crop pests and diseases. However, their extensive use has led to the selection of resistances. This makes the finding of new solutions paramount to countering the economic losses that pests and diseases represent in modern agriculture. Bacillus thuringiensis (Bt) is one of the most reliable alternatives to chemical-based solutions. In this study, we aimed to further expand the global applicability of Bt strains beyond their spores and crystals. To this end, we selected a new Bt strain (BST-122) with relevant toxicity factors and tested its activity against species belonging to different phyla. The spore and crystal mixture showed toxicity to coleopterans. Additionally, a novel Cry5-like protein proved active against the two-spotted spider mite. In vivo and plant assays revealed significant control of the parasitic nematode, Meloidogyne incognita. Surprisingly, our data indicated that the nematocidal determinants may be secreted. When evaluated against phytopathogenic fungi, the strain seemed to decelerate their growth. Overall, our research has highlighted the potential of Bt strains, expanding their use beyond the confinements of spores and crystals. However, further studies are required to pinpoint the factors responsible for the wide host range properties of the BST-122 strain.
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Affiliation(s)
- Argine Unzue
- Institute of Multidisciplinary Research in Applied Biology-IMAB, Universidad Pública de Navarra, 31192 Mutilva, Spain
- Departamento de Investigación y Desarrollo, Bioinsectis SL, Plaza Cein 5, Nave A14, 31110 Noáin, Spain
| | - Carlos J. Caballero
- Departamento de Investigación y Desarrollo, Bioinsectis SL, Plaza Cein 5, Nave A14, 31110 Noáin, Spain
| | - Maite Villanueva
- Departamento de Investigación y Desarrollo, Bioinsectis SL, Plaza Cein 5, Nave A14, 31110 Noáin, Spain
| | - Ana Beatriz Fernández
- Departamento de Investigación y Desarrollo, Bioinsectis SL, Plaza Cein 5, Nave A14, 31110 Noáin, Spain
| | - Primitivo Caballero
- Institute of Multidisciplinary Research in Applied Biology-IMAB, Universidad Pública de Navarra, 31192 Mutilva, Spain
- Correspondence:
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Rodríguez-González Á, Porteous-Álvarez AJ, Val MD, Casquero PA, Escriche B. Toxicity of five Cry proteins against the insect pest Acanthoscelides obtectus (Coleoptera: Chrisomelidae: Bruchinae). J Invertebr Pathol 2019; 169:107295. [PMID: 31783031 DOI: 10.1016/j.jip.2019.107295] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 11/22/2019] [Accepted: 11/24/2019] [Indexed: 11/29/2022]
Abstract
The beetle Acanthoscelides obtectus (Say) causes severe post-harvest losses in the common bean (Phaseolus vulgaris). Under laboratory conditions, the susceptibility of A. obtectus to five coleopteran-specific Cry toxic proteins from Bacillus thuringiensis (Cry1Ba, Cry1Ia, Cry3Aa, Cry7Ab, and Cry23/37) was evaluated. After 30 days exposure, Cry proteins demonstrated high activity against A. obtectus adults (100% mortality). Proteins showed statistical differences in toxicity parameters compared to the control treatment, but the parameters were similar among them, and indicated that the final toxic effects can be observed after the 24th day. The toxic effects on A. obtectus larvae were evaluated indirectly by allowing adults to oviposit on treated beans and recording the emergence of F1 adults. All treatments resulted in a lower rate of successful emergence compared to the control treatment, ranging from 60% (Cry23/37) to 10% (Cry1Ia) reduction in eclosion. Finally, to evaluate the ability of Cry proteins to protect the beans against A. obtectus; the number of beans infested, the number of holes in each bean and bean weight loss were determined 45 days after the treatment. The parameters showed significant bean protection by all Cry proteins analyzed compared to control treatment. Cry23/37 showed the best results, however, results for the other proteins were similar. The proteins belong to different Cry protein families, which suggest that they could be used in combination to increase plant protection without compromising resistance management. Moreover, adult emergence and bean protection results indicate differences among the proteins, which may suggest different modes of action. Our results indicate that the studied Cry proteins can be applied for the control of A. obtectus larvae and adults.
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Affiliation(s)
- Álvaro Rodríguez-González
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain.
| | - Alejandra J Porteous-Álvarez
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain
| | - Mario Del Val
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain
| | - Pedro A Casquero
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain
| | - Baltasar Escriche
- ERI de Biotecnología y Biomedicina (BIOTECMED), Departamento de Genética, Universitat de València, Burjassot 46100, Spain
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Wang Z, Fang L, Zhou Z, Pacheco S, Gómez I, Song F, Soberón M, Zhang J, Bravo A. Specific binding between Bacillus thuringiensis Cry9Aa and Vip3Aa toxins synergizes their toxicity against Asiatic rice borer ( Chilo suppressalis). J Biol Chem 2018; 293:11447-11458. [PMID: 29858245 DOI: 10.1074/jbc.ra118.003490] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 05/28/2018] [Indexed: 11/06/2022] Open
Abstract
The bacterium Bacillus thuringiensis produces several insecticidal proteins, such as the crystal proteins (Cry) and the vegetative insecticidal proteins (Vip). In this work, we report that a specific interaction between two B. thuringiensis toxins creates insecticidal synergism and unravel the molecular basis of this interaction. When applied together, the three-domain Cry toxin Cry9Aa and the Vip Vip3Aa exhibited high insecticidal activity against an important insect pest, the Asiatic rice borer (Chilo suppressalis). We found that these two proteins bind specifically to brush border membrane vesicles of C. suppressalis and that they do not share binding sites because no binding competition was observed between them. Binding assays revealed that the Cry9Aa and Vip3Aa proteins interacted with high affinity. We mapped their specific interacting regions by analyzing binding of Cry9Aa to overlapping fragments of Vip3Aa and by analyzing binding of Vip3Aa to individual domains of Cry9Aa. Binding to peptide arrays helped narrow the binding sites to domain II loop-3 of Cry9Aa and to 428TKKMKTL434 in Vip3Aa. Site-directed mutagenesis confirmed that these binding regions participate in binding that directly correlates with the synergism between the two proteins. In summary, we show that the B. thuringiensis Cry9Aa and Vip3Aa toxins display potent synergy based on a specific interaction between them. Our results further our understanding of the complex synergistic activities among B. thuringiensis toxins and are highly relevant to the development of toxin combinations for effective insect control and for delaying development of insect resistance.
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Affiliation(s)
- Zeyu Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Number 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China; Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Apdo. Postal 510-3, Morelos 62250, Mexico
| | - Longfa Fang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Number 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China
| | - Zishan Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Number 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China
| | - Sabino Pacheco
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Apdo. Postal 510-3, Morelos 62250, Mexico
| | - Isabel Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Apdo. Postal 510-3, Morelos 62250, Mexico
| | - Fuping Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Number 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Apdo. Postal 510-3, Morelos 62250, Mexico
| | - Jie Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Number 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China.
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Apdo. Postal 510-3, Morelos 62250, Mexico.
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Ricietto APS, Gomis-Cebolla J, Vilas-Bôas GT, Ferré J. Susceptibility of Grapholita molesta (Busck, 1916) to formulations of Bacillus thuringiensis, individual toxins and their mixtures. J Invertebr Pathol 2016; 141:1-5. [PMID: 27686262 DOI: 10.1016/j.jip.2016.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/14/2016] [Accepted: 09/23/2016] [Indexed: 11/28/2022]
Abstract
The Oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae), is a major pest of fruit trees worldwide, such as peach and apple. Bacillus thuringiensis has been shown to be an efficient alternative to synthetic insecticides in the control of many agricultural pests. The objective of this study was to evaluate the effectiveness of B. thuringiensis individual toxins and their mixtures for the control of G. molesta. Bioassays were performed with Cry1Aa, Cry1Ac, Cry1Ca, Vip3Aa, Vip3Af and Vip3Ca, as well as with the commercial products DiPel® and XenTari®. The most active proteins were Vip3Aa and Cry1Aa, with LC50 values of 1.8 and 7.5ng/cm2, respectively. Vip3Ca was nontoxic to this insect species. Among the commercial products, DiPel® was slightly, but significantly, more toxic than XenTari®, with LC50 values of 13 and 33ng commercial product/cm2, respectively. Since Vip3A and Cry1 proteins are expressed together in some insect-resistant crops, we evaluated possible synergistic or antagonistic interactions among them. The results showed moderate to high antagonism in the combinations of Vip3Aa with Cry1Aa and Cry1Ca.
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Affiliation(s)
- Ana Paula Scaramal Ricietto
- Departamento de Biologia Geral, Universidade Estadual de Londrina, Londrina, Paraná, Brazil; ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Joaquín Gomis-Cebolla
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | | | - Juan Ferré
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
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Pease CE, López-Olguín JF, Pérez-Moreno I, Marco-Mancebón V. Effects of Kaolin on Lobesia botrana (Lepidoptera: Tortricidae) and Its Compatibility With the Natural Enemy, Trichogramma cacoeciae (Hymenoptera: Trichogrammatidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:740-745. [PMID: 26803817 DOI: 10.1093/jee/tov400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae) is an important grapevine pest in Europe recently encountered in America. Trichogramma cacoeciae Marchal (Hymenoptera: Trichogrammatidae) is amongst the most effective parasitoids for Lepidopteran species. Studies to evaluate the effect of kaolin, an inert, nontoxic mineral, on oviposition, egg hatch, and neonate mortality of these species were carried out. Efficacy on L. botrana neonate larvae, oviposition, and egg hatch was evaluated. Effects of kaolin on parasitism and emergence of T. cacoeciae from L. botrana and Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs were also evaluated. Lobesia botrana egg hatch and oviposition rates were reduced, and neonate larvae mortality was significantly greater in kaolin-treated arenas and when included in synthetic neonate larvae diet. Kaolin had no effect on T. cacoeciae parasitism in both hosts. There was only a slight but statistically insignificant effect on T. cacoeciae progeny emergence from L. botrana eggs and no effect from E. kuehniella. The results involving reductions in L. botrana oviposition and egg hatch and increase in larval mortality with kaolin suggest this compound may contribute to reduction in population densities and can be considered in rational integrated pest management strategies for L. botrana. Due to the laboratory results presented on parasitoid emergence, even though field bioassays would give a more exhaustive evaluation, it appears kaolin can be compatible with T. cacoeciae in L. botrana management.
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9
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Silva MC, Siqueira HAA, Silva LM, Marques EJ, Barros R. Cry Proteins from Bacillus thuringiensis Active against Diamondback Moth and Fall Armyworm. NEOTROPICAL ENTOMOLOGY 2015; 44:392-401. [PMID: 26070631 DOI: 10.1007/s13744-015-0302-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 05/08/2015] [Indexed: 06/04/2023]
Abstract
Biopesticides based on Bacillus thuringiensis and genetically modified plants with genes from this bacterium have been used to control Plutella xylostella (L.) and Spodoptera frugiperda (J.E. Smith). However, the selection pressure imposed by these technologies may undermine the efficiency of this important alternative to synthetic insecticides. Toxins with different modes of action allow a satisfactory control of these insects. The purpose of this study was to characterize the protein and gene contents of 20 B. thuringiensis isolates from soil and insect samples collected in several areas of Northeast Brazil which are active against P. xylostella and S. frugiperda. Protein profiles were obtained by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Polymerase chain reaction assays were used to determine toxin genes present within bacterial isolates. The protein profile of the majority of the isolates produced bands of approximately 130 kDa, suggesting the presence of Cry1, Cry8 and Cry9 proteins. The gene content of the isolates of B. thuringiensis investigated showed different gene profiles. Isolates LIIT-4306 and LIIT-4311 were the most actives against both species, with LC50 of 0.03 and 0.02 × 10(8) spores mL(-1), respectively, for P. xylostella, and LC50 of 0.001 × 10(8) spores mL(-1) for S. frugiperda. These isolates carried the cry1, cry1Aa, cry1Ab, cry1Ac, cry1B, cry1C, cry1D, cry1F, cry2, cry2A, cry8, and cry9C genes. The obtained gene profiles showed great potential for the control of P. xylostella and S. frugiperda, primarily because of the presence of several cry1A genes, which are found in isolates of B. thuringiensis active against these insects.
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Affiliation(s)
- M C Silva
- Depto de Química e Biologia, Univ Estadual do Maranhão, Caxias, MA, Brasil,
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10
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Ortega-López V, Amo-Salas M, Ortiz-Barredo A, Díez-Navajas AM. Male flight phenology of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae) in different wine-growing regions in Spain. BULLETIN OF ENTOMOLOGICAL RESEARCH 2014; 104:566-575. [PMID: 24810404 DOI: 10.1017/s0007485314000339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Lobesia botrana is the most significant pest of grape berries in Spain. Further knowledge of its phenology would enable wine growers to decide on an optimal treatment schedule. The aim of this study is, therefore, to predict the flight peaks of L. botrana in seven wine-growing regions of Spain. The main goal is to provide a prediction model based on meteorological data records. A logistic function model, based on temperature and humidity records, together with an exhaustive statistical analysis, were used to compare the wine-growing regions in which the male flight phenology of L. botrana displays similar patterns and to sort them into groups. By doing so, a joint study of the dynamics of the moth is possible in the regions within each group. A comparison of the prediction errors before and after applying the Touzeau model confirmed that the fit of the latter model is not sufficiently accurate for the regions under study. Moth flight predictions with the logistic function model are good, but accuracy may still be improved by evaluating other non-biotic and biotic factors.
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Affiliation(s)
- V Ortega-López
- Civil Engineering Department,University of Burgos,Calle Villadiego s/n, E-09001 Burgos,Spain
| | - M Amo-Salas
- Mathematics Department,University of Castilla-La Mancha,Camino de Moledores s/n, E-13071 Ciudad Real,Spain
| | - A Ortiz-Barredo
- Plant Production and Protection Department,NEIKER-Tecnalia,E-01080 Vitoria-Gasteiz,Spain
| | - A M Díez-Navajas
- Plant Production and Protection Department,NEIKER-Tecnalia,E-01080 Vitoria-Gasteiz,Spain
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11
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Ruiz de Escudero I, Banyuls N, Bel Y, Maeztu M, Escriche B, Muñoz D, Caballero P, Ferré J. A screening of five Bacillus thuringiensis Vip3A proteins for their activity against lepidopteran pests. J Invertebr Pathol 2014; 117:51-5. [PMID: 24508583 DOI: 10.1016/j.jip.2014.01.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 01/21/2014] [Accepted: 01/24/2014] [Indexed: 10/25/2022]
Abstract
Five Bacillus thuringiensis Vip3A proteins (Vip3Aa, Vip3Ab, Vip3Ad, Vip3Ae and Vip3Af) and their corresponding trypsin-activated toxins were tested for their toxicity against eight lepidopteran pests: Agrotis ipsilon, Helicoverpa armigera, Mamestra brassicae, Spodoptera exigua, Spodoptera frugiperda, Spodoptera littoralis, Ostrinia nubilalis and Lobesia botrana. Toxicity was first tested at a high dose at 7 and 10 days. No major differences were found when comparing protoxins vs. trypsin-activated toxins. The proteins that were active against most of the insect species were Vip3Aa, Vip3Ae and Vip3Af, followed by Vip3Ab. Vip3Ad was non-toxic to any of the species tested. Considering the results by insect species, A. ipsilon, S. frugiperda and S. littoralis were susceptible to Vip3Aa, Vip3Ab, Vip3Ae and Vip3Af; S. exigua was susceptible to Vip3Aa and Vip3Ae, and moderately susceptible to Vip3Ab; M. brassicae and L. botrana were susceptible to Vip3Aa, Vip3Ae and Vip3Af; H. armigera was moderately susceptible to Vip3Aa, Vip3Ae and Vip3Af, and O. nubilalis was tolerant to all Vip3 proteins tested, although it showed some susceptibility to Vip3Af. The results obtained will help to design new combinations of insecticidal protein genes in transgenic crops or in recombinant bacteria for the control of insect pests.
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Affiliation(s)
- Iñigo Ruiz de Escudero
- Instituto de Agrobiotecnología, CSIC-UPNA, Gobierno de Navarra, Campus Arrosadía, 31192 Mutilva, Navarra, Spain; Laboratorio de Entomología Agrícola y Patología de Insectos, Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain
| | - Núria Banyuls
- Departamento de Genética, Facultad de CC. Biológicas, Universitat de València, 46100 Valencia, Spain
| | - Yolanda Bel
- Departamento de Genética, Facultad de CC. Biológicas, Universitat de València, 46100 Valencia, Spain
| | - Mireya Maeztu
- Instituto de Agrobiotecnología, CSIC-UPNA, Gobierno de Navarra, Campus Arrosadía, 31192 Mutilva, Navarra, Spain
| | - Baltasar Escriche
- Departamento de Genética, Facultad de CC. Biológicas, Universitat de València, 46100 Valencia, Spain
| | - Delia Muñoz
- Laboratorio de Entomología Agrícola y Patología de Insectos, Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain
| | - Primitivo Caballero
- Instituto de Agrobiotecnología, CSIC-UPNA, Gobierno de Navarra, Campus Arrosadía, 31192 Mutilva, Navarra, Spain; Laboratorio de Entomología Agrícola y Patología de Insectos, Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain
| | - Juan Ferré
- Departamento de Genética, Facultad de CC. Biológicas, Universitat de València, 46100 Valencia, Spain.
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Specific binding of Bacillus thuringiensis Cry2A insecticidal proteins to a common site in the midgut of Helicoverpa species. Appl Environ Microbiol 2008; 74:7654-9. [PMID: 18931285 DOI: 10.1128/aem.01373-08] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
For a long time, it has been assumed that the mode of action of Cry2A toxins was unique and different from that of other three-domain Cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. However, based on the homology of the tertiary structure among three-domain Cry toxins, similar modes of action for all of them are expected. To confirm this hypothesis, binding assays were carried out with (125)I-labeled Cry2Ab. Saturation assays showed that Cry2Ab binds in a specific and saturable manner to brush border membrane vesicles (BBMVs) of Helicoverpa armigera. Homologous-competition assays with (125)I-Cry2Ab demonstrated that this toxin binds with high affinity to binding sites in H. armigera and Helicoverpa zea midgut. Heterologous-competition assays showed a common binding site for three toxins belonging to the Cry2A family (Cry2Aa, Cry2Ab, and Cry2Ae), which is not shared by Cry1Ac. Estimation of K(d) (dissociation constant) values revealed that Cry2Ab had around 35-fold less affinity than Cry1Ac for BBMV binding sites in both insect species. Only minor differences were found regarding R(t) (concentration of binding sites) values. This study questions previous interpretations from other authors performing binding assays with Cry2A toxins and establishes the basis for the mode of action of Cry2A toxins.
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