Toxicity of Seven Bacillus thuringiensis Cry Proteins Against Cylas puncticollis and Cylas brunneus (Coleoptera: Brentidae) Using a Novel Artificial Diet

2010 ◽  
Vol 103 (4) ◽  
pp. 1493-1502 ◽  
Author(s):  
Moses Ekobu ◽  
Maureen Solera ◽  
Samuel Kyamanywa ◽  
Robert O. M. Mwanga ◽  
Benson Odongo ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Artificial Diet ◽  
Cry Proteins ◽  
Cylas Puncticollis ◽  
Cylas Brunneus

scholarly journals New Strategy for Identification of Novel cry-Type Genes from Bacillus thuringiensis Strains

2005 ◽  
Vol 71 (2) ◽  
pp. 761-765 ◽  
Author(s):  
Corina M. Berón ◽  
Leonardo Curatti ◽  
Graciela L. Salerno
Keyword(s):  
Bacillus Thuringiensis ◽  
Phylogenetic Distance ◽  
Cloning And Sequencing ◽  
Degenerate Primers ◽  
Dna Templates ◽  
Cry Proteins ◽  
New Strategy ◽  
Genes Encoding ◽  
Encoding Protein

ABSTRACT We designed five degenerate primers for detection of novel cry genes from Bacillus thuringiensis strains. An efficient strategy was developed based on a two-step PCR approach with these primers in five pair combinations. In the first step, only one of the primer pairs is used in the PCR, which allows amplification of DNA fragments encoding protein regions that include consensus domains of representative proteins belonging to different Cry groups. A second PCR is performed by using the first-step amplification products as DNA templates and the set of five primer combinations. Cloning and sequencing of the last-step amplicons allow both the identification of known cry genes encoding Cry proteins covering a wide phylogenetic distance and the detection and characterization of cry-related sequences from novel B. thuringiensis isolates.

Characterization of cry Genes in a Mexican Bacillus thuringiensis Strain Collection

1998 ◽  
Vol 64 (12) ◽  
pp. 4965-4972 ◽  
Author(s):  
Alejandra Bravo ◽  
Sergio Sarabia ◽  
Lorena Lopez ◽  
Hernesto Ontiveros ◽  
Carolina Abarca ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Specific Primers ◽  
Cry Proteins ◽  
Pcr Product ◽  
Strain Collection ◽  
Lepidopteran Insects ◽  
Ecological Patterns ◽  
Biogeographical Regions ◽  
Selection Of

ABSTRACT Mexico is located in a transition zone between the Nearctic and Neotropical biogeographical regions and contains a rich and unique biodiversity. A total of 496 Bacillus thuringiensis strains were isolated from 503 soil samples collected from the five macroregions of the country. The characterization of the strain collection provided useful information on the ecological patterns of distribution of B. thuringiensis and opportunities for the selection of strains to develop novel bioinsecticidal products. The analysis of the strains was based on multiplex PCR with novel general and specific primers that could detect the cry1,cry3, cry5, cry7, cry8,cry9, cry11, cry12,cry13, cry14, cry21, andcyt genes. The proteins belonging to the Cry1 and Cry9 groups are toxic for lepidopteran insects. The Cry3, Cry7, and Cry8 proteins are active against coleopteran insects. The Cry5, Cry12, Cry13, and Cry14 proteins are nematocidal. The Cry11, Cry21, and Cyt proteins are toxic for dipteran insects. Six pairs of general primers are used in this method. Strains for which unique PCR product profiles were obtained with the general primers were further characterized by additional PCRs with specific primers. Strains containingcry1 genes were the most abundant in our collection (49.5%). Thirty-three different cry1-type profiles were identified. B. thuringiensis strains harboringcry3 genes represented 21.5% of the strains, and 7.9% of the strains contained cry11 and cyt genes.cry7, cry8, and cry9 genes were found in 0.6, 2.4, and 2.6% of the strains, respectively. No strains carrying cry5, cry12, cry13,cry14, or cry21 genes were found. Finally, 14% of the strains did not give any PCR product and did not react with any polyclonal antisera. Our results indicate the presence of strains that may harbor potentially novel Cry proteins as well as strains with combinations of less frequently observed cry genes.

scholarly journals Occurrence and Ear Damage of Helicoverpa zea on Transgenic Bacillus thuringiensis Maize in the Field in Texas, U.S. and Its Susceptibility to Vip3A Protein

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 102 ◽  
Author(s):  
Fei Yang ◽  
José C. Santiago González ◽  
Jayme Williams ◽  
Donald C. Cook ◽  
Ryan T. Gilreath ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
Sustainable Use ◽  
Leaf Tissue ◽  
Corn Earworm ◽  
Laboratory Population ◽  
Bt Maize ◽  
Cry Proteins ◽  
Damage Area ◽  
The U.S

The corn earworm, Helicoverpa zea (Boddie), is a major pest of Bacillus thuringiensis (Bt) maize and cotton in the U.S.. Reduced efficacy of Bt plants expressing Cry1 and Cry2 against H. zea has been reported in some areas of the U.S.. In this study, we evaluated the occurrence and ear damage of H. zea on transgenic Bt maize expressing Cry proteins or a combination of Vip3A and Cry proteins in the field in Texas in 2018. We found that the occurrence of H. zea larvae and the viable kernel damage area on the ear were not different between non-Bt maize and Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteins. A total of 67.5% of the pyramided Bt maize expressing Cry1Ab+Cry1F+Vip3A was damaged by 2nd–4th instar larvae of H. zea. Diet bioassays showed that the resistance ratio against Vip3Aa51 for H. zea obtained from Cry1Ab+Cry1F+Vip3A maize was 20.4 compared to a field population collected from Cry1F+Cry1A.105+Cry2Ab2 maize. Leaf tissue bioassays showed that 7-day survivorship on WideStrike3 (Cry1F+Cry1Ac+Vip3A) cotton leaves was significantly higher for the H. zea population collected from Cry1Ab+Cry1F+Vip3A maize than for a Bt-susceptible laboratory population. The results generated from this study suggest that H. zea has evolved practical resistance to Cry1 and Cry2 proteins. Therefore, it is crucial to ensure the sustainable use of the Vip3A technology in Bt maize and cotton.

scholarly journals Rearrangement of N-Terminal α-Helices of Bacillus thuringiensis Cry1Ab Toxin Essential for Oligomer Assembly and Toxicity

Toxins ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 647
Author(s):  
Sabino Pacheco ◽  
Jean Piere Jesus Quiliche ◽  
Isabel Gómez ◽  
Jorge Sánchez ◽  
Mario Soberón ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Conformational Changes ◽  
Membrane Integrity ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Membrane Vesicles ◽  
Insect Midgut ◽  
Cry Proteins ◽  
Cry1ab Toxin ◽  
Domain I

Cry proteins produced by Bacillus thuringiensis are pore-forming toxins that disrupt the membrane integrity of insect midgut cells. The structure of such pore is unknown, but it has been shown that domain I is responsible for oligomerization, membrane insertion and pore formation activity. Specifically, it was proposed that some N-terminal α-helices are lost, leading to conformational changes that trigger oligomerization. We designed a series of mutants to further analyze the molecular rearrangements at the N-terminal region of Cry1Ab toxin that lead to oligomer assembly. For this purpose, we introduced Cys residues at specific positions within α-helices of domain I for their specific labeling with extrinsic fluorophores to perform Föster resonance energy transfer analysis to fluorescent labeled Lys residues located in Domains II–III, or for disulfide bridges formation to restrict mobility of conformational changes. Our data support that helix α-1 of domain I is cleaved out and swings away from the toxin core upon binding with Manduca sexta brush border membrane vesicles. That movement of helix α-2b is also required for the conformational changes involved in oligomerization. These observations are consistent with a model proposing that helices α-2b and α-3 form an extended helix α-3 necessary for oligomer assembly of Cry toxins.

scholarly journals Unshared binding sites for Bacillus thuringiensis Cry3Aa and Cry3Ca proteins in the weevil Cylas puncticollis (Brentidae)

Toxicon ◽  
2016 ◽  
Vol 122 ◽  
pp. 50-53 ◽  
Author(s):  
Patricia Hernández-Martínez ◽  
Natalia Mara Vera-Velasco ◽  
Baltasar Escriche
Keyword(s):  
Bacillus Thuringiensis ◽  
Binding Sites ◽  
Cylas Puncticollis

scholarly journals The Independent Biological Activity of Bacillus thuringiensis Cry23Aa Protein Against Cylas puncticollis

2020 ◽  
Vol 11 ◽  
Author(s):  
Patricia Hernández-Martínez ◽  
Ayda Khorramnejad ◽  
Katterine Prentice ◽  
Ascensión Andrés-Garrido ◽  
Natalia Mara Vera-Velasco ◽  
...  
Keyword(s):  
Biological Activity ◽  
Bacillus Thuringiensis ◽  
Cylas Puncticollis

Resistance to the Weevils Cylas puncticollis and Cylas brunneus Conferred by Sweetpotato Root Surface Compounds

2013 ◽  
Vol 61 (34) ◽  
pp. 8141-8147 ◽  
Author(s):  
M. Otema Anyanga ◽  
Harriet Muyinza ◽  
Herbert Talwana ◽  
David R. Hall ◽  
Dudley I. Farman ◽  
...  
Keyword(s):  
Root Surface ◽  
Surface Compounds ◽  
Cylas Puncticollis ◽  
Cylas Brunneus
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