Association analysis between serotype, cry gene content, and toxicity to Helicoverpa armigera larvae among Bacillus thuringiensis isolates native to Spain

2005 ◽  
Vol 90 (2) ◽  
pp. 91-97 ◽  
Author(s):  
Clara Martínez ◽  
Jorge E. Ibarra ◽  
Primitivo Caballero
Keyword(s):  
Bacillus Thuringiensis ◽  
Association Analysis ◽  
Helicoverpa Armigera ◽  
Gene Content ◽  
Cry Gene ◽  
Helicoverpa Armígera

scholarly journals Bacillus thuringiensis Bel Protein Enhances the Toxicity of Cry1Ac Protein to Helicoverpa armigera Larvae by Degrading Insect Intestinal Mucin

2009 ◽  
Vol 75 (16) ◽  
pp. 5237-5243 ◽  
Author(s):  
Shangling Fang ◽  
Li Wang ◽  
Wei Guo ◽  
Xia Zhang ◽  
Donghai Peng ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Trichoplusia Ni ◽  
Knockout Mutant ◽  
Gene Encoding ◽  
In Vitro Degradation ◽  
Intestinal Mucin ◽  
Helicoverpa Armígera ◽  
Cry1ac Protein

ABSTRACT Bacillus thuringiensis has been used as a bioinsecticide to control agricultural insects. Bacillus cereus group genomes were found to have a Bacillus enhancin-like (bel) gene, encoding a peptide with 20 to 30% identity to viral enhancin protein, which can enhance viral infection by degradation of the peritrophic matrix (PM) of the insect midgut. In this study, the bel gene was found to have an activity similar to that of the viral enhancin gene. A bel knockout mutant was constructed by using a plasmid-free B. thuringiensis derivative, BMB171. The 50% lethal concentrations of this mutant plus the cry1Ac insecticidal protein gene were about 5.8-fold higher than those of the BMB171 strain. When purified Bel was mixed with the Cry1Ac protein and fed to Helicoverpa armigera larvae, 3 μg/ml Cry1Ac alone induced 34.2% mortality. Meanwhile, the mortality rate rose to 74.4% when the same amount of Cry1Ac was mixed with 0.8 μg/ml of Bel. Microscopic observation showed a significant disruption detected on the midgut PM of H. armigera larvae after they were fed Bel. In vitro degradation assays showed that Bel digested the intestinal mucin (IIM) of Trichoplusia ni and H. armigera larvae to various degrading products, similar to findings for viral enhancin. These results imply Bel toxicity enhancement depends on the destruction of midgut PM and IIM, similar to the case with viral enhancin. This discovery showed that Bel has the potential to enhance insecticidal activity of B. thuringiensis-based biopesticides and transgenic crops.

scholarly journals Controle de Helicoverpa armigera (Lepidoptera: Noctuidae) em soja com inseticidas químicos e biológicos

2016 ◽  
Vol 51 (5) ◽  
pp. 527-536 ◽  
Author(s):  
Cassiano Carlos Kuss ◽  
Rejane Cristina Roppa Kuss Roggia ◽  
Claudir José Basso ◽  
Maria Cristina Neves de Oliveira ◽  
Osmar Henrique de Castro Pias ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

Resumo: O objetivo deste trabalho foi avaliar o desempenho de inseticidas autorizados emergencialmente para o controle de Helicoverpa armigera (Lepidoptera: Noctuidae) em soja. Sete inseticidas foram pulverizados em campo e, após 24 horas, folhas do ponteiro foram coletadas e oferecidas para lagartas de 2o instar em laboratório. Lagartas do 4o instar receberam a última folha trifoliolada que se encontrava completamente expandida no momento da pulverização. Outro grupo foi exposto a folhas coletadas a partir de 72 horas da pulverização. Em campo, seis inseticidas foram pulverizados e, em seguida, as plantas foram infestadas com lagartas de 2o e 3o instar. No primeiro estudo, flubendiamida, clorantraniliprole, clorfenapir, indoxacarbe e metoxifenozida causaram 100% de mortalidade do 4o instar aos oito dias após o início da exposição, enquanto baculovírus e Bacillus thuringiensis (Bt) propiciaram mortalidade de 60-75%, que evoluiu para 88-90% ao final da fase de pupa. Para o 2o instar, apenas flubendiamida e clorantraniliprole proporcionaram mortalidade de 100%. Flubendiamida, clorantraniliprole e clorfenapir apresentaram o menor tempo letal para o 4o instar, e flubendiamida e clorantraniliprole, para o 2o instar. Após 72 horas da pulverização, o desempenho dos inseticidas foi insatisfatório. Em campo, houve eficiência satisfatória de flubendiamida, espinosade, baculovírus e Bt sobre lagartas de 2o e 3o instar.

scholarly journals Knockout of three aminopeptidase N genes does not affect susceptibility of Helicoverpa armigera larvae to Bacillus thuringiensis Cry1A and Cry2A toxins

2019 ◽  
Vol 27 (3) ◽  
pp. 440-448 ◽  
Author(s):  
Jing Wang ◽  
Ya‐Yun Zuo ◽  
Ling‐Li Li ◽  
Hui Wang ◽  
Shao‐Yan Liu ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Aminopeptidase N ◽  
Helicoverpa Armígera
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