How to cope with insect resistance to Bt toxins?
Transgenic Bt crops producing insecticidal crystalline proteins from Bacillus thuringiensis, so-called Cry toxins, have proved useful in controlling insect pests. However, the future of Bt crops is threatened by the evolution of insect resistance. Understanding how Bt toxins work and how insects become resistant will provide the basis for taking measures to counter resistance. Here we review possible mechanisms of resistance and different strategies to cope with resistance, such as expression of several toxins with different modes of action in the same plant, modified Cry toxins active against resistant insects, and the potential use of Cyt toxins or a fragment of cadherin receptor. These approaches should provide the means to assure the successful use of Bt crops for an extended period of time.
Bravo
Alejandra
A
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 62250, Morelos, Mexico.
Soberón
Mario
M
D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics* / Q000494:pharmacology; D006376:Helminths / Q000187:drug effects; D007313:Insecta / Q000187:drug effects; D007305:Insecticide Resistance; D010572:Pest Control, Biological / Q000379:methods; D030821:Plants, Genetically Modified / Q000235:genetics*; D015202:Protein Engineering; D011498:Protein Precursors / Q000235:genetics* / Q000494:pharmacology
C049673:Bacillus thuringiensis ovicidal toxin; C029103:Bacillus thuringiensis protoxin; D001427:Bacterial Toxins; D011498:Protein Precursors