MOLECULAR AND GENETIC MECHANISMS OF HESSIAN FLY RESISTANCE IN SOFT WINTER WHEAT
Location: Crop Production and Pest Control Research
Title: Localization and Characterization of 170 BAC-derived clones and mapping of Ninety-Four Microsatellites in the Hessian Fly
Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2009
Publication Date: July 10, 2009
Citation: Schemerhorn, B.J., Crane, Y.M., Morton, P.K., Aggarwal, R., Stuart, J.J. 2009. Localization and Characterization of 170 BAC-derived clones and mapping of Ninety-Four Microsatellites in the Hessian Fly. Journal of Heredity. Available at: http://jhered.oxfordjournals.org/cgi/content/abstract/esp045.
Interpretive Summary: Microsatellites are genetic markers based on variation in tandem-repeat counts. Because microsatellites are typically neutral, co-dominant, and easily observed as length polymorphisms, they have become one of the most popular genetic markers since their discovery in 1981. Recently, our laboratory created microsatellite-enriched libraries, but lacked the information on their chromosomal locations. Previously, using an enriched-library method, developed in our laboratory, we discovered a set of PCR-based microsatellite markers covering the Hessian fly genome. In this study, we have identified clones that contain these markers, and used them to determine their physical location on polytene chromosomes. This is the first physical map of microsatellite markers in Hessian fly, and the markers can be applied to population analysis, recombinational mapping, and QTL (Quantitative Trait Loci) analysis. One-hundred-seventy clones, representing 94 primer pairs, were successfully mapped to the four chromosomes. This work will benefit researchers as they attempt to better understand the Hessian fly-wheat interaction utilizing genomic sequences and locations on the chromosomes, and better pinpoint locales for perspective virulence/avirulence candidate genes. This work opens up new dimensions in locating candidate virulence/avirulence genes and also gives more information for possible QTL mapping, recombinational mapping and population genetics.
Ninety-four microsatellites from enriched genomic libraries of Hessian fly (Mayetiola destructor (Say)) were localized to 170 cognate clones in a Hessian fly bacterial artificial chromosome (BAC) library. These microsatellite-positive BAC clones were physically mapped to polytene chromosomes by fluorescent in situ hybridization (FISH) using a modified superpooling method. The mapped microsatellite loci can be used to study the genetic diversity and population structure of Hessian fly.