Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2004
Publication Date: 9/20/2004
Citation: Johnson, A.J., Schemerhorn, B.J., Shukle, R.H. 2004. A first assessment of mitochondrial DNA variation and geographic distribution of haplotypes in the Hessian fly (Diptera: Cecidomyiidae). Annals of the Entomological Society of America.97(5):940-048. Interpretive Summary: The Hessian fly is a destructive pest of wheat and resistant wheat is the most economical and environmentally sound method of control. However, the use of resistant wheat has resulted in the selection of biotypes that can survive on formerly resistant wheat. The pest is thought to have evolved with wheat in Southwest Asia, the presumed center of origin of wheat. From this center of origin the pest was spread by human activity to the Middle East and across North Africa and around the Mediterranean Basin. To date there is no knowledge of the ancestry of Hessian fly populations in North America. Ancestry and the possibility of multiple introductions have implications concerning variability in the pest and its ability to respond to resistant wheat. We have used molecular markers to make an initial assessment of genetic variation and possible ancestry of Hessian fly in North America as well as in populations from North Africa, the Mediterranean Basin, and the Middle East. Results suggest a southern European ancestry for Hessian fly in North America is possible and that more than one introduction may have occurred but additional analyses will have to confirm this. Scientists and breeders facing the challenge of ensuring durable resistance to Hessian fly will benefit from this knowledge, which will provide a better understanding of the ability of the fly in North America to adapt to genes for resistance. The agricultural community (crop producers and commodity groups) will benefit from improved pest control that increases yield and quality without increasing costs.
Technical Abstract: Domain III of the mitochondrial 12S rRNA gene from Hessian fly, Mayetiola destructor (Say), was sequenced in 21 populations from the United States, two populations from Canada, five populations from the Mediterranean basin, one population from Southwest Asia, and one population from New Zealand. From the total alignment seven unique mitochondrial DNA (mtDNA) sequences (haplotypes) were identified. Of the seven 12 S haplotypes only three (haplotypes 1, 2, and 3) occurred in populations from North America, indicating these were most likely the introduced haplotypes. Haplotypes were not restricted to any given biotype of M. destructor as defined by virulence to resistance genes in wheat. Thus, neutral markers did not show structure based on biotype. Populations of M. destructor showed a predominance of one haplotype over the others in specific geographic regions. However, Wolbachia DNA was not detected in any population, indicating that inheritance patterns of mtDNA in M. destructor were most likely due to repeated bottlenecks leading to the expansion of one lineage over another. The complete complement of 12S sequences in the M. destructor populations was subjected to a phylogenetic reconstruction by using haplotypes 1 and 3 of the gall midge Orseolia oryzae (Wood-Mason), as outgroups. Results from this initial study indicate a more robust phylogenetic reconstruction and analysis of population history will test the hypothesis of a single introduction of M. destructor into North America.