Development of a Hessian fly BAC-based genome map and the identification of vH13 avirulence gene candidates

Rajat Aggarwal, Purdue University

Abstract

The Hessian fly (Mayetiola destructor) is an important insect pest of wheat (Triticum spp.). It is also a member of one of the largest and most economically important families of the Diptera (the gall midges or Cecidomyiidae). As such, it has potential as a model insect for studies of plant-insect interactions. However, our knowledge pertaining to the molecular mechanism underlying wheat-Hessian fly interaction is limited. This is primarily due to a lack of any cloned avirulence gene in this insect. Research presented in this study was undertaken to identify putative vH13 avirulence genes. It was necessary to develop a high-resolution genomic map and estimate recombination rate near the vH13 gene. Chapter one focuses on application of Fiber-FISH in insects. Recombination rate near the vH13 locus in Hessian fly was determined and genomic rearrangement associated with Medea (Maternal Effect Dominant Embryonic Arrest) was discovered. Chapter two discusses the development of the first detailed high-resolution integrated genetic and physical map of the Hessian fly genome. The BAC based physical map has been anchored to the polytene chromosomes of Hessian fly. The map has enormous potential to aid further genomic research in this economically important pest and provide the necessary framework for the assembly of the Hessian fly genome sequence. The third chapter presents the results of an extensive chromosome walk undertaken to map the vH13 gene to a 1-cM genetic interval and 80-kb physical interval within a single BAC clone. The BAC clone containing the gene was sequenced and analyzed to identify vH13 gene candidates.

Degree

Ph.D.

Advisors

Stuart, Purdue University.

Subject Area

Entomology

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