title: A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.
abstract: Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50) of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f) was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects.
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Chen
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Chenxi
authors.initials: C
authors.lastname: Liu
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Yutao
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Yongdong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Entomology, University of Arizona, Tucson, AZ, 85721, United States of America.
authors.forename: Xianchun
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Entomology, University of Arizona, Tucson, AZ, 85721, United States of America.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Tabashnik
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Kongming
authors.initials: K
authors.lastname: Wu
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism* / Q000494:pharmacology; D018826:CD13 Antigens / Q000378:metabolism; D004731:Endotoxins / Q000378:metabolism* / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics; D006460:Hemolysin Proteins / Q000378:metabolism* / Q000494:pharmacology; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D007305:Insecticide Resistance; D009036:Moths / Q000187:drug effects* / Q000502:physiology; D010446:Peptide Fragments / Q000378:metabolism
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; D010446:Peptide Fragments; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D000469:Alkaline Phosphatase; D018826:CD13 Antigens