Susceptibility of nine insect species to infection by Bacillus thuringiensis var. thuringiensis

1966 ◽  
Vol 8 (3) ◽  
pp. 347-350 ◽  
Author(s):  
M.U. Shaikh ◽  
F.O. Morrison
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Species

Antagonism between Formulations of Different Bacillus thuringiensis Subspecies in Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae)

1998 ◽  
Vol 33 (2) ◽  
pp. 129-135 ◽  
Author(s):  
A. O. Ameen ◽  
J. R. Fuxa ◽  
A. R. Richter
Keyword(s):  
Bacillus Thuringiensis ◽  
Heliothis Virescens ◽  
Helicoverpa Zea ◽  
Insect Species ◽  
Median Lethal Concentrations ◽  
Lepidoptera Noctuidae

Interactions between formulations of the aizawai and kurstaki subspecies of Bacillus thuringiensis Berliner were evaluated by bioassay in Heliothis virescens (F.) and Helicoverpa zea (Boddie). In preliminary experiments, a formulation of subspecies aizawai, Xentari AS®, had significantly (P < 0.05) higher median lethal concentrations (LC50s) in both insect species than formulations based on subspecies kurstaki. Helicoverpa zea was significantly (P < 0.05) more susceptible than H. virescens to one formulation of subspecies kurstaki (Dipel ES®), but the two insects did not differ in susceptibility to Xentari AS® or to a second formulation of subspecies kurstaki (Dipel 6AF®). In H. virescens, Xentari AS® was additive with Dipel 6AF® and significantly (P< 0.05) antagonistic with Dipel ES® and with a third formulation of subspecies kurstaki, Dipel 48A®. In H. zea, Xentari AS® was significantly antagonistic with all three formulations of subspecies kurstaki. This suggests that certain toxin combinations from B. thuringiensis subspecies might not be effective for managing H. virescens and H. zea populations.

scholarly journals Genetic Knockouts Indicate That the ABCC2 Gene in the Bollworm Helicoverpa Zea Is Not a Major Receptor for the Cry1Ac Insecticidal Protein.

2021 ◽  
Author(s):  
Omaththage P. Perera ◽  
Nathan S LIttle ◽  
Heba Abdelgaffar ◽  
Juan Luis Jurat-Fuentes ◽  
Gadi V. P. Reddy
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
Insect Species ◽  
Insecticidal Protein ◽  
Functional Domains ◽  
Atp Binding ◽  
Atp Binding Cassette Transporter ◽  
Major Pest ◽  
Moth Species ◽  
Atp Binding Cassette

Members of the insect ATP binding cassette transporter subfamily C2 (ABCC2) in several moth species are known as receptors for the Cry1Ac insecticidal protein from Bacillus thuringiensis (Bt). Mutations that abolish the functional domains of ABCC2 are known to cause resistance to Cry1Ac, although the reported levels of resistance vary widely depending on insect species. In this study, the function of the ABCC2 gene as putative Cry1Ac receptor in Helicoverpa zea, a major pest of over 300 crops, was evaluated using CRISPR/Cas9 to progressively eliminate different functional ABCC2 domains. Results from bioassays with edited insect lines support that muta-tions in ABCC2 was associated with Cry1Ac resistance ratios (RR) ranging from 7.3- to 39.8-fold. No significant differences in susceptibility to Cry1Ac were detected between H. zea with partial or complete ABCC2 knockout, although highest levels of tolerance were observed when knocking out half of ABCC2. Based on >500-1,000-fold RRs reported in similar studies for closely related moth species, the low RRs observed in H. zea knockouts support that ABCC2 is not a major Cry1Ac receptor in this insect.

Interaction of larval age and antibiotic on the susceptibility of three insect species to Bacillus thuringiensis

1981 ◽  
Vol 37 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Clayton C. Beegle ◽  
Leslie C. Lewis ◽  
Robert E. Lynch ◽  
Adelaido J. Martinez
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Species

Recherche de souches naturelles du Bacillus thuringiensis dans différents biotopes, à travers le monde

1997 ◽  
Vol 43 (4) ◽  
pp. 337-343 ◽  
Author(s):  
Josette Chaufaux ◽  
Michel Marchal ◽  
Nathalie Gilois ◽  
Isabelle Jehanno ◽  
Christophe Buisson
Keyword(s):  
Bacillus Thuringiensis ◽  
Screening Programme ◽  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Protein Band ◽  
Soil Samples ◽  
Insect Species ◽  
Entomopathogenic Bacteria ◽  
Molecular Masses ◽  
Lepidoptera Noctuidae

A screening programme to isolate new strains of the entomopathogenic bacteria Bacillus thuringiensis was undertaken on 4887 samples of various sources from 101 countries over the world: 1260 strains of the bacillus were isolated. Dust from mills and silos, as well as insects from nature, were more successful sources than soil samples, which emphasizes the diversity of biotopes where the bacillus is encountered. Electrophoretic characterization reveals the genetic variability of the species. An analysis of insecticidal properties of the isolated strains was performed on four insect species: Plutella xylostella (Lepidoptera: Plutellidae), Spodoptera littoralis (Lepidoptera: Noctuidae), Phaedon cochleariae (Coleoptera: Chrysomelidae), and Locusta migratoria or Schistocerca gregaria (Orthoptera: Acrididae). The most frequent strains (54%) were producing crystals constituted of proteins with molecular masses of 130–140 or 66 and 130–140 kDa and were toxic to Lepidoptera larvae. A significant number of strains (31) were larvicidal to Coleoptera while only one, H14 serotype, was active on Diptera. Numerous strains synthesize crystals made up of proteins with size differing from the already known toxins. Most of these strains were nonactive against the four insect species tested. One strain showing a protein band at 73 kDa had no insecticidal activity against P. cochleariae while it was toxic to P. xylostella.Key words: Bacillus thuringiensis, new strains, distribution, Lepidoptera, Coleoptera.

scholarly journals Insecticidal Activity of Bacillus thuringiensis Proteins against Coleopteran Pests

Toxins ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 430 ◽  
Author(s):  
Mikel Domínguez-Arrizabalaga ◽  
Maite Villanueva ◽  
Baltasar Escriche ◽  
Carmen Ancín-Azpilicueta ◽  
Primitivo Caballero
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Mode Of Action ◽  
Insect Species ◽  
Specific Information ◽  
Cry Proteins ◽  
Microbial Insecticide ◽  
Bt Toxins ◽  
Vip Proteins ◽  
Agro Forestry

Bacillus thuringiensis is the most successful microbial insecticide agent and its proteins have been studied for many years due to its toxicity against insects mainly belonging to the orders Lepidoptera, Diptera and Coleoptera, which are pests of agro-forestry and medical-veterinary interest. However, studies on the interactions between this bacterium and the insect species classified in the order Coleoptera are more limited when compared to other insect orders. To date, 45 Cry proteins, 2 Cyt proteins, 11 Vip proteins, and 2 Sip proteins have been reported with activity against coleopteran species. A number of these proteins have been successfully used in some insecticidal formulations and in the construction of transgenic crops to provide protection against main beetle pests. In this review, we provide an update on the activity of Bt toxins against coleopteran insects, as well as specific information about the structure and mode of action of coleopteran Bt proteins.

Morphological diversity and toxicity of delta-endotoxin produced by various strains of Bacillus thuringiensis

1995 ◽  
Vol 85 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Tipvadee Attathom ◽  
Wiboon Chongrattanameteekul ◽  
Jariya Chanpaisang ◽  
Ratchanee Siriyan
Keyword(s):  
Bacillus Thuringiensis ◽  
Rice Bran ◽  
Morphological Diversity ◽  
Crystal Protein ◽  
Insect Species ◽  
Alternative Strategies ◽  
New Subspecies ◽  
Crystal Proteins ◽  
Morphological Studies ◽  
Delta Endotoxin

AbstractLocal isolates of Bacillus thuringiensis were isolated from infected rice stemborers, soils, rice bran and rice mill dust. Of 83 isolates serotyped by B. thuringiensis H-antisera, 13 serotypes were identified. Those serotypes were assigned to B. thuringiensis of subspecies canadensis, galleriae, kenyae, kurstaki, neoleonensis, aizawai, alesti, entomocidus, tochigiensis and tolworthi. Three serotypes, 3a:3c:3d, 5a:5b/21 and 17/27, were unnamed and portend to be new subspecies. Morphological studies of delta-endotoxin or crystal protein of each subspecies showed significant differences in size and shape. Bipyramidal crystals, spherical and cuboidal crystals and the combinations of these structures were observed. Toxicity of sporulated cultures and isolated crystal proteins of B. thuringiensis strains to five species of economically important insects were determined using diet incorporation bioassays. Extracted crystal proteins from certain B. thuringiensis subspecies were highly toxic to some insect species. These have the potential of providing alternative strategies for utilizing B. thuringiensis for controlling insects.

scholarly journals Correspondence of High Levels of Beta-Exotoxin I and the Presence of cry1B in Bacillus thuringiensis

2002 ◽  
Vol 68 (9) ◽  
pp. 4182-4186 ◽  
Author(s):  
Sylvain Espinasse ◽  
Michel Gohar ◽  
Josette Chaufaux ◽  
Christophe Buisson ◽  
Stéphane Perchat ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Species ◽  
Anthonomus Grandis ◽  
Genetic Determinants ◽  
Natural Isolates ◽  
Culture Supernatants

ABSTRACT Examination of 640 natural isolates of Bacillus thuringiensis showed that the 58 strains (9%) whose supernatants were toxic to Anthonomus grandis (Coleoptera: Curculionidae) produced between 10 and 175 μg of β-exotoxin I per ml. We also found that 55 (46%) of a sample of 118 strains whose culture supernatants were not toxic to A. grandis nevertheless produced between 2 and 5 μg/ml. However, these amounts of β-exotoxin I were below the threshold for detectable toxicity against this insect species. Secretion of large amounts of β-exotoxin I was strongly associated with the presence of cry1B and vip2 genes in the 640 natural B. thuringiensis isolates studied. We concluded that strains carrying cry1B and vip2 genes also possess, on the same plasmid, genetic determinants necessary to promote high levels of production of β-exotoxin I.

scholarly journals Genetic Knockouts Indicate That the ABCC2 Protein in the Bollworm Helicoverpa zea Is Not a Major Receptor for the Cry1Ac Insecticidal Protein

Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1522
Author(s):  
Omaththage P. Perera ◽  
Nathan S. Little ◽  
Heba Abdelgaffar ◽  
Juan Luis Jurat-Fuentes ◽  
Gadi V. P. Reddy
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Zea ◽  
Insect Species ◽  
Insecticidal Protein ◽  
Functional Domains ◽  
Atp Binding ◽  
Atp Binding Cassette Transporter ◽  
Major Pest ◽  
Moth Species ◽  
Abcc2 Protein

Members of the insect ATP binding cassette transporter subfamily C2 (ABCC2) in several moth species are known as receptors for the Cry1Ac insecticidal protein from Bacillus thuringiensis (Bt). Mutations that abolish the functional domains of ABCC2 are known to cause resistance to Cry1Ac, although the reported levels of resistance vary widely depending on insect species. In this study, the function of the ABCC2 gene as a putative Cry1Ac receptor in Helicoverpa zea, a major pest of over 300 crops, was evaluated using CRISPR/Cas9 to progressively eliminate different functional ABCC2 domains. Results from bioassays with edited insect lines support that mutations in ABCC2 were associated with Cry1Ac resistance ratios (RR) ranging from 7.3- to 39.8-fold. No significant differences in susceptibility to Cry1Ac were detected between H. zea with partial or complete ABCC2 knockout, although the highest levels of tolerance were observed when knocking out half of ABCC2. Based on >500–1000-fold RRs reported in similar studies for closely related moth species, the low RRs observed in H. zea knockouts support that ABCC2 is not a major Cry1Ac receptor in this insect.

scholarly journals Bacillus thuringiensis Cry1Ac Toxin-Binding and Pore-Forming Activity in Brush Border Membrane Vesicles Prepared from Anterior and Posterior Midgut Regions of Lepidopteran Larvae

2008 ◽  
Vol 74 (6) ◽  
pp. 1710-1716 ◽  
Author(s):  
Ana Rodrigo-Simón ◽  
Silvia Caccia ◽  
Juan Ferré
Keyword(s):  
Bacillus Thuringiensis ◽  
Brush Border ◽  
Mode Of Action ◽  
Pore Formation ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Insect Species ◽  
Binding Parameters ◽  
Larval Midgut ◽  
Posterior Midgut

ABSTRACT It is generally accepted that Bacillus thuringiensis Cry toxins insert into the apical membrane of the larval midgut after binding to specific receptors, and there is evidence that the distribution of binding molecules along the midgut is not uniform. By use of the voltage-sensitive dye DiSC3(5) and 125I-labeled Cry1Ac, we have measured the effect of Cry1Ac in terms of permeabilization capacity and of binding parameters on brush border membrane vesicles (BBMV) prepared from the anterior and the posterior regions of the larval midgut from two insect species, Manduca sexta and Helicoverpa armigera. The permeabilizing activity was significantly higher with BBMV from the posterior region than with the one observed in the anterior region in both insect species. Instead, 125I-Cry1Ac bound specifically to BBMV from the two midgut regions, with no significant differences in the binding parameters between the anterior and posterior regions within an insect species. N-acetylgalactosamine inhibition patterns on pore formation and binding differed between anterior and posterior midgut regions and between species, providing evidence of a multifaceted involvement of the sugar in the Cry1Ac mode of action. The analysis of binding and pore formation in different midgut regions could be an effective method to study differences in the mode of action of Cry1Ac toxin in different species.

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