title: Specificity determinants for Cry insecticidal proteins: Insights from their mode of action.
abstract: Insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) are used as active components of biopesticides and as plant incorporated protectants in transgenic crops. One of the most relevant attributes of these Bt protein-based insecticidal technologies is their high specificity, which assures lack of detrimental effects on non-target insects, vertebrates and the environment. The identification of specificity determinants in Bt insecticidal proteins could guide risk assessment for novel insecticidal proteins currently considered for commercialization. In this work we review the available data on specificity determinants of crystal (Cry) insecticidal proteins as the Bt toxins most well characterized and used in transgenic crops. The multi-step mode of action of the Cry insecticidal proteins allows various factors to potentially affect specificity determination and here we define seven levels that could influence specificity. The relative relevance of each of these determinants on efficacy of transgenic crops producing Cry insecticidal proteins is also discussed.
authors.affiliation: Department of Entomology and Plant Pathology, University of Tennessee, Knoxville 37996, USA. Electronic address: jurat@utk.edu.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Jurat-Fuentes
authors.affiliation: School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Crickmore
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry*; D004731:Endotoxins / Q000737:chemistry*; D006460:Hemolysin Proteins / Q000737:chemistry*; D010572:Pest Control, Biological / Q000379:methods*; D030821:Plants, Genetically Modified; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Bacillus thuringiensis; Bt crops; Cry toxin; Mode of action; Specificity