title: Fitness costs and stability of Cry1Ab resistance in sugarcane borer, Diatraea saccharalis (F.).
abstract: The sugarcane borer, Diatraea saccharalis (F.), is a major target species of transgenic corn expressing Bacillus thuringiensis (Bt) proteins in South America and the U.S. mid-south region. In this study, the fitness of seven insect genotypes of D. saccharalis were assayed on non-toxic diet, which included a Cry1Ab-susceptible strain (SS-2009), two Cry1Ab-resistant strains (RR-43A(BC), RR-L5B(BC)), and four F1 hybrids (F1-R43A(m)S(f), F1-R43A(f)S(m), F1-R5B(m)S(f), and F1-R5B(f)S(m)). The F1 hybrids were generated by reciprocal crosses of SS-2009 with RR-43ABC and RR-L5BBC, respectively. Biological parameters measured were neonate-to-pupa survivorship, neonate-to-pupa development time, pupal mass, pupa-to-adult emergence rate, and progeny (neonates) production. The overall performance of the two resistant strains and the four F1 genotypes was either similar or better than SS-2009 for all biological parameters measured, suggesting a lack of fitness costs associated with the Cry1Ab resistance traits in both RR-43A(BC) and RR-L5B(BC). In addition, resistance stability was evaluated by measuring the Cry1Ab susceptibility of RR-43A(BC) and RR-L5B(BC) in the absence of selection pressure. Laboratory bioassays showed that larval mortality of the two resistant strains did not significantly increase after selection pressure was removed for 16 generations across all Cry1Ab concentrations assayed. The results provide valuable information on assessing resistance risk and developing effective management strategies for the sustainable use of Bt corn technology.
authors: Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA; Cotton Research Institute, Shanxi Academy of Agricultural Sciences, Yuncheng, Shanxi, China.
authors: Liping
authors: L
authors: Zhang
authors: Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors: B Rogers
authors: BR
authors: Leonard
authors: Monsanto Company, Chesterfield, MO 63017, USA.
authors: Mao
authors: M
authors: Chen
authors: Monsanto Company, Chesterfield, MO 63017, USA.
authors: Thomas
authors: T
authors: Clark
authors: Monsanto Company, Chesterfield, MO 63017, USA.
authors: Konasale
authors: K
authors: Anilkumar
authors: Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA. Electronic address: fhuang@agcenter.lsu.edu.
authors: Fangneng
authors: F
authors: Huang
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics*; D004731:Endotoxins / Q000235:genetics*; D056084:Genetic Fitness / Q000235:genetics*; D006460:Hemolysin Proteins / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D007915:Lepidoptera / Q000235:genetics*; D010572:Pest Control, Biological / Q000379:methods; D030821:Plants, Genetically Modified / Q000235:genetics
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Bacillus thuringiensis; Diatraea saccharalis; Fitness; Resistance; Stability; Zea mays