MOLECULAR AND GENETIC MECHANISMS OF HESSIAN FLY RESISTANCE IN SOFT WINTER WHEAT
Location: Crop Production and Pest Control Research
Title: Use of a nuclear marker to assess population structure in Hessian fly (Mayetiola destructor)
Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 26, 2011
Publication Date: July 1, 2011
Citation: Johnson, A.J., Morton, P.K., Schemerhorn, B.J., Shukle, R.H. 2011. Use of a nuclear marker to assess population structure in Hessian fly (Mayetiola destructor). Annals of the Entomological Society of America. 104:666-674.
Interpretive Summary: The Hessian fly is a pest of wheat throughout most wheat producing regions worldwide and is the most important insect pest of wheat in the southeastern soft-winter-wheat production region of the United States. Because of the lack of an effective “fly-free” date as a cultural practice for fall planting in much of the southeastern United States, genetically resistant wheat is the only effective means for preventing yield losses due to Hessian fly infestation. While the use of resistant wheat is an effective means for controlling Hessian fly, it places a selective pressure on Hessian fly populations and has led to the appearance of biotypes of the pest that can overcome the resistance offered by formerly resistant wheat. Due to the economic impact of yield losses due to Hessian fly the insect has been intensely studied. However, the focus of most of the research has been on the genetic interaction between the insect and wheat. Very little research has focused on Hessian fly population genetic structure, which is a fundamental prerequisite for understanding risk assessment to deployment of genetic resistance and development of a rational deployment strategy. In this study we have used mitochondrial and nuclear DNA markers to investigate the population structure of Hessian fly in North America and to understand the relationships between Old and New World populations of Hessian fly. Results provide a better understanding of the genetic structure of Hessian fly populations and insight into introduction events and genetic diversity of Hessian fly in the United States. This knowledge will benefit scientists and breeders facing the challenge of devising more durable deployment strategies for resistance in wheat to the Hessian fly. Wheat producers and commodity groups will also benefit from this knowledge with improved pest control without increased cost.
Mitochondrial and nuclear DNA markers were used to assess the phylogeographic relationships between introduced North American and native Old World populations of Hessian fly (Mayetiola destructor), one of the most common and destructive pests of wheat throughout the world. Domain III of the mitochondrial 12S ribosomal RNA (rRNA) gene and intron 1 from the nuclear white gene were sequenced from twelve collections across North America, Southern Europe, North Africa, and the Middle East. Seven mitochondrial haplotypes and thirty-three alleles of intron 1 from white were identified. TCS network analysis support previous findings in regards to ancestral mitochondrial haplotype relationships, and structure analyses indicate that these 12 collections can be divided into three populations: Middle East, Mediterranean, and North America. Spain, Khazakstan, and North America all share alleles, and some individuals fall into 2 populations while Syria and Khazakstan also share alleles with the Middle East and Mediterranean populations. AMOVA results showed significant genetic variability within each population; however, populations were less than 20% variable between populations leading to little differences between New World and Old World populations. Despite separation by over 200 years since Hessian fly’s introduction, populations in North America still reflect the diversity found in native populations in the Old World that are outside the presumed center of origin, the Middle East.