Submitted to: Annals of the Entomological Society of America
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/16/2004
Publication Date: 9/1/2004
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):940-948. Interpretive Summary: The Hessian fly is a major pest of wheat in the United States and most other production areas of the world. It is thought to be endemic to the southern Caucasus and southwest Asia, the center of origin of wheat, and to have dispersed to North Africa and Europe. The primary method of control is through resistant wheat. However, biotypes of the insect capable of surviving on formerly resistant wheat are a threat to the durability of resistance. The rate of migration among populations is fundamental to the rate at which virulent biotypes can evolve and spread. Understanding this process is necessary to the protection of wheat. While Hessian fly populations have been sampled to monitor biotype composition, no molecular analyses have been conducted. We have used variation in DNA to study Hessian fly populations. Knowledge gained from this study will reveal information about migration among Hessian fly populations, geographic locations in the Old World from which the fly was introduced into North America, and the amount of diversity in the fly populations introduced. This information will help scientist and wheat breeders continue to protect the wheat crop with effective resistance to Hessian fly.
Technical Abstract: Intraspecific variation in mitochondrial DNA (mtDNA) was examined in the Hessian fly, Mayetiola destructor (Say). Domain III of the mitochondrial 12S rRNA gene was amplified by polymerase chain reaction (PCR) and sequenced in samples from various geographic origins and laboratory biotype lines. A phylogenetic tree inferred from the 12S rRNA nucleotide sequence data revealed three haplotypes. Genetic distance estimates among the haplotypes ranged from 0.7% to 1.6%. Based on these estimates, and the use of a molecular clock, mitochondrial haplotypes in M. destructor shared a common ancestral mitochondrial genome approximately 0.9 to 2 million years ago. Frequency of haplotypes in geographic populations and laboratory biotypes was estimated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Haplotype 1 was predominant in samples of populations from most regions of the United States as well as from New Zealand. Haplotypes 2 and 3 were predominant in samples of populations from eastern North Carolina, southwestern Indiana, and populations from Manitoba and Ontario, Canada. Biotypes of M. destructor belonged to all haplotypes and the biotype composition of field populations probably reflects recent selection pressure from genes for resistance in hexaploid wheat. Additionally, inheritance patterns of mtDNA in M. destructor were not correlated with Wolbachia infection. From analysis of mtDNA in M. destructor we argue there was more than one introduction into the United States from different geographic locations in the Old World. Analysis of additional populations from the Middle East, North Africa, and Europe will reveal further information concerning historical events, phylogeographic patterns, and insight into population structure for M. destructor.