ARS | Publication request: Assessment of Structural Variation and Molecular Mapping of Insertion Sites of Desmar-like Elements in the Hessian Fly Genome

Submitted to: Insect Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 14, 2010
Publication Date: December 5, 2010
Citation: Behura, S.K., Shukle, R.H., Stuart, J.J. 2010. Assessment of Structural Variation and Molecular Mapping of Insertion Sites of Desmar-like Elements in the Hessian Fly Genome. Insect Molecular Biology. 19(6):707-715.

Interpretive Summary: The Hessian fly is a major insect pest of wheat in the United States. Genetic resistance in wheat is the most effective method for control of Hessian fly. However, new biotypes of the insect that can overcome formerly resistant wheat continue to appear. We have identified “mobile” genetic elements in the DNA of the Hessian fly. These mobile elements or “jumping genes” are known to cause mutations in genes. Further, the recent molecular characterization of a Hessian fly gene for virulence, a gene allowing the insect to live on resistant wheat, showed that the mutation causing virulence was due to insertion into the gene by a mobile genetic element. We have determined the location of these mobile genetic elements in the DNA of the Hessian fly. This knowledge can help in identifying more virulence genes in the Hessian fly that allow the pest to attack and overcome resistant wheat. Results from this study will help breeders and scientists facing the challenge of devising innovative methods to ensure the durability of resistant wheat to prevent yield loss due to Hessian fly infestation. The agricultural community (crop producers and commodity groups) will benefit from improved pest control that increases yield and quality without increasing costs.

Technical Abstract: Hessian fly (Mayetiola destructor) is an agriculturally important pest of wheat. A mariner element (Desmar1) has been previously identified in the Hessian fly genome. Using Desmar1 as a probe, we isolated individual copies of Desmar-like elements from the Hessian fly genome cloned in bacterial artificial chromosomes (BAC) and studied their structural variability and flanking DNA sequences. The partial Desmar-like copies are relatively more abundant (~64%) than full length copies (~36%) in the Hessian fly genome. Most of the full length copies are consistently flanked by an EcoRI restriction site after 32-bp from one end and 66-bp from the other end of the mariner. Using an AFLP-PCR based method, we identified segregating polymorphisms associated with Desmar elements in a F2 mapping population. We were able to use the segregation data to localize the chromosomal position of three Desmar elements by linkage analysis. As paternal chromosomes are eliminated in Hessian fly during early embryogenesis, two-third of the AFLPs were expected to be polymorphic in the mapping population and this was observed for AFLPs anchored to full length Desmar copies but not to the partial copies. Thus, our data indicates that dead and partial Desmar-like copies are probably associated with lower polymorphic regions and may represent mariner graveyards in the Hessian fly genome.