Search results for "Cry1Ac"
showing 5 items of 45 documents
Biochemistry and genetics of insect resistance to Bacillus thuringiensis.
2001
▪ Abstract Bacillus thuringiensis (Bt) is a valuable source of insecticidal proteins for use in conventional sprayable formulations and in transgenic crops, and it is the most promising alternative to synthetic insecticides. However, evolution of resistance in insect populations is a serious threat to this technology. So far, only one insect species has evolved significant levels of resistance in the field, but laboratory selection experiments have shown the high potential of other species to evolve resistance against Bt. We have reviewed the current knowledge on the biochemical mechanisms and genetics of resistance to Bt products and insecticidal crystal proteins. The understanding of th…
Genetic and Biochemical Characterization of Field-Evolved Resistance to Bacillus thuringiensis Toxin Cry1Ac in the Diamondback Moth, Plutella xyloste…
2004
ABSTRACT The long-term usefulness of Bacillus thuringiensis Cry toxins, either in sprays or in transgenic crops, may be compromised by the evolution of resistance in target insects. Managing the evolution of resistance to B. thuringiensis toxins requires extensive knowledge about the mechanisms, genetics, and ecology of resistance genes. To date, laboratory-selected populations have provided information on the diverse genetics and mechanisms of resistance to B. thuringiensis , highly resistant field populations being rare. However, the selection pressures on field and laboratory populations are very different and may produce resistance genes with distinct characteristics. In order to better…
Resistance toBacillus thuringiensis Cry1Ac toxin in three strains ofHeliothis virescens: Proteolytic and SEM study of the larval midgut
1999
In a previous study, we demonstrated that resistance to Bacillus thuringiensis toxins in Heliothis virescens might be related to differences in the composition of the proteolytic extracts from insect midgut. There, we found specific proteolytic bands present in the gut extracts of the resistant strain and absent from the susceptible one. Here we report related facts using a new resistant strain (KCB) and a cross between the two strains used in our previous study. As would be expected, no quantitative differences in total proteolytic activity were found between the strains, although qualitative differences related to the presence or absence of specific proteolytic activity bands using SDS-PA…
Susceptibility to Cry proteins of a SpanishOstrinia nubilalisglasshouse population repeatedly sprayed withBacillus thuringiensisformulations
2013
Ostrinia nubilalis Hubner (Lepidoptera: Crambidae), a major pest of corn in temperate climates, can feed on other crops due to its polyphagous behaviour. In particular, this species became a serious problem in some sweet pepper commercial glasshouses in south-eastern Spain repeatedly sprayed with Bacillus thuringiensis (Bt) products to control Spodoptera exigua Hubner (Lepidoptera: Noctuidae). The susceptibility of an O. nubilalis colony established from individuals collected in these Bt-sprayed glasshouses was compared with a reference laboratory colony. Differences in susceptibility between the two colonies to Cry1Aa, Cry1Ab, Cry1Ac and Cry2Aa proteins were found. However, our results ind…
Binding analysis of Bacillus thuringiensis Cry1 proteins in the sugarcane borer, Diatraea saccharalis (Lepidoptera: Crambidae).
2015
Sugarcane borer (Diatraea saccharalis, F.) is an important corn pest in South America and United States. The aim of the present study was to analyze the susceptibility and binding interactions of three Cry1A proteins and Cry1Fa in a Brazilian D. saccharalis population. The results showed that Cry1Ab was the most active, followed by Cry1Ac, Cry1Fa and Cry1Aa. All Cry1-biotinylated proteins tested bound specifically to the D. saccharalis brush border membrane vesicles (BBMV). Heterologous competition assays showed shared binding sites for all Cry1A proteins and another one shared by Cry1Fa and Cry1Ab. Thus, pyramiding Cry1Aa/Cry1Ac and Cry1F proteins would be a recommended strategy for managi…