Resistance is non-futile: resistance to Cry5B in the nematode Caenorhabditis elegans

The nematode, Caenorhabditis elegans, can be mutated to resistance to the Cry5B toxin of Bacillus thuringiensis. By cloning and characterization of these C. elegans resistance genes, we have determined that a major mechanism by which C. elegans resists Cry5B is by loss of function mutations in any one of four gylcosyltransferase genes that glycosylate glycolipids specific to arthropods. Without correct gylcosylation, binding of Cry5B is greatly impaired in C. elegans. That these specific arthroseries glycolipids do not occur in vertebrates potentially helps explain why Cry toxins are specific for arthropods.