Bt Toxin Resistance from Loss of a Putative Carbohydrate-Modifying Enzyme
Joel S. Griffitts,
Johanna L. Whitacre,
Daniel
E. Stevens,
Raffi V. Aroian*
The development of resistance is the main threat to the long-term
use of toxins from Bacillus thuringiensis (Bt) in transgenic plants. Here we report the cloning of a Bt toxin resistance gene, Caenorhabditis elegans bre-5, which encodes a putative
-1,3-galactosyltransferase. Lack of bre-5 in the
intestine led to resistance to the Bt toxin Cry5B. Wild-type but not
bre-5 mutant animals were found to uptake toxin into their
gut cells, consistent with bre-5 mutants lacking toxin-binding sites on their apical gut. bre-5 mutants
displayed resistance to Cry14A, a Bt toxin lethal to both nematodes and insects; this indicates that resistance by loss of carbohydrate modification is relevant to multiple Bt toxins.
Section of Cell and Developmental Biology, University of
California, San Diego, La Jolla, CA 92093, USA.
*
To whom correspondence should be addressed. E-mail:
raroian{at}ucsd.edu