Resistance to Cry toxins and epithelial healing

Resistance to Cry toxins can develop by alterations in any of the steps in the Cry toxin mode of action. Most characterized mechanisms of resistance to Cry toxins involve alterations in enzymatic toxin processing or toxin interaction with receptors in the insect midgut epithelium. Previous reports have suggested an alternative mechanism of resistance to Cry1Ac toxin in Heliothis virescens larvae involving enhanced midgut regeneration after toxin-induced injury. Our current hypothesis is that as midgut mature cells interact with Cry1Ac and undergo injury, stem cells divide and differentiate to replace damaged mature cells. Considering this hypothesis, resistant H. virescens larvae may display a more effective regenerative mechanism that prevents compromising epithelial integrity. We report the detection of differences in the proteins secreted by mature cells upon Cry toxin treatment and an efficient regenerative response to intoxication in midgut cells from Cry1Acresistant H. virescens larvae.