Evolution of Bacillus thuringiensis Cry toxins insecticidal activity

• Published in: Microbial biotechnology Vol. 6; no. 1; pp. 17 - 26
• Main Authors: Bravo, Alejandra, Gómez, Isabel, Porta, Helena, García‐Gómez, Blanca Ines, Rodriguez‐Almazan, Claudia, Pardo, Liliana, Soberón, Mario
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-01-2013; John Wiley & Sons, Inc
• Subjects: Amino acids; Animals; Bacillus thuringiensis; Bacillus thuringiensis - genetics; Bacillus thuringiensis - metabolism; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacterial Toxins - chemistry; Bacterial Toxins - genetics; Bacterial Toxins - metabolism; Biological evolution; Crops; Endotoxins - chemistry; Endotoxins - genetics; Endotoxins - metabolism; Evolution; Evolution & development; Evolution, Molecular; Gene mapping; Genetic engineering; Genetic Engineering - methods; Hemolysin Proteins - chemistry; Hemolysin Proteins - genetics; Hemolysin Proteins - metabolism; Insecticides - metabolism; Insects; Mapping; Minireview; Mode of action; Moths - metabolism; Mutagenesis; Mutation; Pest control; Pest Control, Biological; Pests; Phylogenetics; Proteins; Toxicity; Toxins; Transgenic plants
• ISSN: 1751-7915; 1751-7915
• DOI: 10.1111/j.1751-7915.2012.00342.x

Summary
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.