Skip to Main Content
Cyt1Aa protein of Bacillus thuringiensis is toxic to the Cottonwood Leaf Beetle, Chrysomela scripta, and suppresses high levels of resistance to Cry3AaAuthor(s): Brian A. Federici; Leah S. Bauer
Source: Applied and Environmental Microbiology. 64(11): 4368-4371.
Publication Series: Scientific Journal (JRNL)
Station: North Central Research Station
PDF: View PDF (342.1 KB)
DescriptionThe insecticidal activity of Bacillus thuringiensis is due primarily to Cry and Cyt proteins. Cry proteins are typically toxic to lepidopterous, coleopterous, or dipterous insects, whereas the known toxicity of Cyt proteins is limited to dipterans. We report here that a Cyt protein, Cyt1Aa, is also highly toxic to the cottonwood leaf beetle, Chrysomela scripta, with a median lethal concentration of 2.5 ng/mm2 of leaf surface for second-instar larvae. Additionally, we show that Cyt1Aa suppresses resistance to Cry3Aa greater than 5,000-fold in C. scripta, a level only partially overcome by Cry1Ba due to cross-resistance. Studies of the histopathology of C. scripta larvae treated with Cyt1Aa revealed disruption and sloughing of midgut epithelial cells, indicating that its mechanism of action against C. scripta is similar to that observed in mosquito and blackfly larvae. These novel properties suggest that Cyt proteins may have an even broader spectrum of activity against insects and, owing to their different mechanism of action in comparison to Cry proteins, might be useful in managing resistance to Cry3 and possibly other Cry toxins used in microbial insecticides and transgenic plants.
- Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat.
- During the capture process some typographical errors may occur.
- Please contact Sharon Hobrla, email@example.com if you notice any errors which make this publication unusable.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationFederici, Brian A.; Bauer, Leah S. 1998. Cyt1Aa protein of Bacillus thuringiensis is toxic to the Cottonwood Leaf Beetle, Chrysomela scripta, and suppresses high levels of resistance to Cry3Aa. Applied and Environmental Microbiology. 64(11): 4368-4371.
- Optimization of Cry3A yields in Bacillus thuringiensis by use of sporulation-dependent promoters in combination with the STAB-SD mRNA sequence
- Bacillus thuringiensis pore-forming toxins trigger massive shedding of GPI-anchored aminopeptidase N from gypsy moth midgut epithelial cells
- Localization of Bacillus thuringiensis Cry1A toxin-binding molecules in gypsy moth larval gut sections using fluorescence microscopy
XML: View XML