Biotech Updates

Bt Cry and Cyt Mutants for Overcoming Insect Resistance

June 8, 2012

Cry and Cyt proteins from Bacillus thuringiensis (Bt) are used globally to control insect pests, either as insect spray or expressed in Bt crops. A team of scientists from Universidad Nacional Autónoma de México reviewed the constructions of Cry and Cyt anti-toxins to gain information for developing strategies to counter insects' resistance to native Cry and Cyt toxins.

Mario Soberón and colleagues found that the non-toxic helix α-4 mutants of Cry1Ab could oligomerize and interact with native toxin (Cry1AMod) forming inactive hetero-oligomers which blocks the toxicity of native Cry1Ab. On the other hand, the N-terminal domain of Cyt1A containing the helix-bundle also shows a dominant negative phenotype inhibiting native Cyt1Aa toxicity. Based on the results, Cry and Cyt mutants have the potential to be used as anti-toxins in certain environments while Cry1AMod toxins could counter resistance to Cry1A toxin in strains with different mechanisms of resistance.

For more details about the study, visit