Letters in Applied Microbiology (2001) 32, 362-367

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L.L. Loguercio, C.G. Santos, M.R. Barreto, C.T. Guimaraes and E. Paiva (2001)
Association of PCR and feeding bioassays as a large-scale method to screen tropical Bacillus thuringiensis isolates for a cry constitution with higher insecticidal effect against Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae
Letters in Applied Microbiology 32 (5), 362-367
Abstract: Aims: To verify whether the presence of any of the cry1C, 1D, 1E and 1F genes could be associated with high toxicity against fall armyworm.
Methods and Results: A sample of 60 strains from a large collection of tropical Bacillus thuringiensis (B.t.) isolates was subjected to feeding bioassays and gene-specific PCR. Positive amplification of cry-specific fragments, so confirmed by sequencing, revealed that cry1C was ubiquitous and distributed among high and low mortality classes, cry1D was underrepresented and showed no clear association to high toxicity, and cry1F was not detected. The presence of cry1E significantly correlated to high levels of insecticidal activity, as estimated by linear regression analysis.
Conclusions: The PCR amplification of cry1E-specific fragments alone appears to be sufficient to identify B.t. strains with high mortality levels against tropical armyworm.
Significance and Impact of the Study: The approach presented is promising as a simple and efficient method for first-tier, marker-assisted screening of environment-specific B.t. germplasm effective in controlling a single target pest.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Leandro Lopes Loguercio

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection


Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.


Spodoptera frugiperda
Bacillus thuringiensis Cry1C-toxin (entomopathogen) Spodoptera frugiperda
Bacillus thuringiensis Cry1E-toxin (biocontrol agent) Spodoptera frugiperda