title: Evolution of Bacillus thuringiensis Cry toxins insecticidal activity.
abstract: Insecticidal Cry proteins produced by Bacillus thuringiensis are use worldwide in transgenic crops for efficient pest control. Among the family of Cry toxins, the three domain Cry family is the better characterized regarding their natural evolution leading to a large number of Cry proteins with similar structure, mode of action but different insect specificity. Also, this group is the better characterized regarding the study of their mode of action and the molecular basis of insect specificity. In this review we discuss how Cry toxins have evolved insect specificity in nature and analyse several cases of improvement of Cry toxin action by genetic engineering, some of these examples are currently used in transgenic crops. We believe that the success in the improvement of insecticidal activity by genetic evolution of Cry toxins will depend on the knowledge of the rate-limiting steps of Cry toxicity in different insect pests, the mapping of the specificity binding regions in the Cry toxins, as well as the improvement of mutagenesis strategies and selection procedures.
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México. Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Bravo
authors.forename: Isabel
authors.initials: I
authors.lastname: Gómez
authors.forename: Helena
authors.initials: H
authors.lastname: Porta
authors.forename: Blanca Ines
authors.initials: BI
authors.lastname: García-Gómez
authors.forename: Claudia
authors.initials: C
authors.lastname: Rodriguez-Almazan
authors.forename: Liliana
authors.initials: L
authors.lastname: Pardo
authors.forename: Mario
authors.initials: M
authors.lastname: Soberón
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics* / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004731:Endotoxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D005818:Genetic Engineering / Q000379:methods; D006460:Hemolysin Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007306:Insecticides / Q000378:metabolism; D009036:Moths / Q000378:metabolism*; D010572:Pest Control, Biological
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis