title: Genetic markers for western corn rootworm resistance to Bt toxin.
abstract: Western corn rootworm (WCR) is a major maize (Zea mays L.) pest leading to annual economic losses of more than 1 billion dollars in the United States. Transgenic maize expressing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely used for the management of WCR. However, cultivation of Bt-expressing maize places intense selection pressure on pest populations to evolve resistance. Instances of resistance to Bt toxins have been reported in WCR. Developing genetic markers for resistance will help in characterizing the extent of existing issues, predicting where future field failures may occur, improving insect resistance management strategies, and in designing and sustainably implementing forthcoming WCR control products. Here, we discover and validate genetic markers in WCR that are associated with resistance to the Cry3Bb1 Bt toxin. A field-derived WCR population known to be resistant to the Cry3Bb1 Bt toxin was used to generate a genetic map and to identify a genomic region associated with Cry3Bb1 resistance. Our results indicate that resistance is inherited in a nearly recessive manner and associated with a single autosomal linkage group. Markers tightly linked with resistance were validated using WCR populations collected from Cry3Bb1 maize fields showing significant WCR damage from across the US Corn Belt. Two markers were found to be correlated with both diet (R2 = 0.14) and plant (R2 = 0.23) bioassays for resistance. These results will assist in assessing resistance risk for different WCR populations, and can be used to improve insect resistance management strategies.
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Lex E
authors.initials: LE
authors.lastname: Flagel
authors.affiliation: Monsanto Company, Creve Coeur, Missouri.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Swarup
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Mao
authors.initials: M
authors.lastname: Chen
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Christopher
authors.initials: C
authors.lastname: Bauer
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Humphrey
authors.initials: H
authors.lastname: Wanjugi
authors.affiliation: Monsanto Company, Creve Coeur, Missouri.
authors.forename: Matthew
authors.initials: M
authors.lastname: Carroll
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Patrick
authors.initials: P
authors.lastname: Hill
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Meghan
authors.initials: M
authors.lastname: Tuscan
authors.affiliation: Department of Entomology, Ohio Agricultural Research and Development Center, Wooster, Ohio.
authors.forename: Raman
authors.initials: R
authors.lastname: Bansal
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Ronald
authors.initials: R
authors.lastname: Flannagan
authors.affiliation: Monsanto Company, Chesterfield, Missouri.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Clark
authors.affiliation: Department of Entomology, Ohio Agricultural Research and Development Center, Wooster, Ohio.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Michel
authors.affiliation: Monsanto Company, Creve Coeur, Missouri graham.p.head@monsanto.com barry.s.goldman@monsanto.com.
authors.forename: Graham P
authors.initials: GP
authors.lastname: Head
authors.affiliation: Monsanto Company, Chesterfield, Missouri graham.p.head@monsanto.com barry.s.goldman@monsanto.com.
authors.forename: Barry S
authors.initials: BS
authors.lastname: Goldman
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000187:drug effects / Q000235:genetics*; D004731:Endotoxins / Q000633:toxicity*; D017344:Genes, Insect; D005819:Genetic Markers; D007305:Insecticide Resistance / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide
chemical_list: C507666:Cry3Bbl endotoxin, Bacillus thuringiensis; D004731:Endotoxins; D005819:Genetic Markers
keywords: Bacillus thuringiensis; Diabrotica virgifera virgifera; genetic marker; insect resistance; western corn rootworm