title: Effect of crop plants on fitness costs associated with resistance to Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in cabbage loopers.
abstract: Fitness costs associated with resistance to Bacillus thuringiensis (Bt) toxins critically impact the development of resistance in insect populations. In this study, the fitness costs in Trichoplusia ni strains associated with two genetically independent resistance mechanisms to Bt toxins Cry1Ac and Cry2Ab, individually and in combination, on four crop plants (cabbage, cotton, tobacco and tomato) were analyzed, in comparison with their near-isogenic susceptible strain. The net reproductive rate (R0) and intrinsic rate of increase (r) of the T. ni strains, regardless of their resistance traits, were strongly affected by the host plants. The ABCC2 gene-linked mechanism of Cry1Ac resistance was associated with relatively low fitness costs, while the Cry2Ab resistance mechanism was associated with higher fitness costs. The fitness costs in the presence of both resistance mechanisms in T. ni appeared to be non-additive. The relative fitness of Bt-resistant T. ni depended on the specific resistance mechanisms as well as host plants. In addition to difference in survivorship and fecundity, an asynchrony of adult emergence was observed among T. ni with different resistance mechanisms and on different host plants. Therefore, mechanisms of resistance and host plants available in the field are both important factors affecting development of Bt resistance in insects.
authors: Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA.|Department of Entomology, Nanjing Agricultural University, Nanjing 210095, China.
authors: Ran
authors: R
authors: Wang
authors: Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA.
authors: Guillaume
authors: G
authors: Tetreau
authors: Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456, USA.
authors: Ping
authors: P
authors: Wang
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000633:toxicity*; D001937:Brassica / Q000469:parasitology*; D018556:Crops, Agricultural / Q000187:drug effects / Q000502:physiology*; D004731:Endotoxins / Q000633:toxicity*; D006460:Hemolysin Proteins / Q000633:toxicity*; D006790:Host-Parasite Interactions / Q000187:drug effects; D007305:Insecticide Resistance / Q000187:drug effects*; D007700:Kinetics; D007814:Larva / Q000187:drug effects; D009036:Moths / Q000254:growth & development; D010058:Oviposition / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects; D011679:Pupa / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis