Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Construction Of A BAC Library For Soybean PI 229358 And Identification Of Clones Associated With A Defoliating Insect Resistance QTL

Shuquan Zhu¹ , Chris A. Saski² , Jeff P. Tomkins² , H. Roger Boerma¹ , John N. All³ , Wayne A. Parrott¹

¹  Center for Applied Genetic Technologies and Department of Crop & Soil Sciences, University of Georgia, 111 Riverbend Rd, Athens, GA 30606, USA

²  Clemson University Genomics Institute, Clemson University, Clemson, SC 29634, USA

³  Department of Entomology, University of Georgia, Athens, GA 30606, USA

Positional cloning of an insect resistance QTL requires the construction of a large-insert genomic DNA library. Until now, none of the soybean BAC libraries has been made from insect resistant genotypes. To facilitate cloning of a major defoliating insect resistance QTL previously identified and fine-scale mapped, a BAC library for PI 229358 was constructed and characterized. The Hind-III BAC library contains 55, 296 clones with about 4.2% chloroplast DNA content, as determined by hybridizing whole library filters with five different soybean chloroplast genes as probes. A random sampling of 192 BAC clones indicates an insert size range of 30 to 320 kb, with about 84% of the BAC clones equal to or greater than 100 kb, and approximately 4% clones having no inserts. The overall average insert size is about 131 kb. This library represents about 6.5 soybean genome equivalents, allowing a 99% probability of recovering any specific sequence of interest. BAC filters were screened with two genomic DNA probes obtained from flanking sequences of two SSR markers, Sat_258 and Satt702, which flank the major insect resistance QTL and are about 0.5 cM apart on linkage group M of the soybean genetic map. Only two positive BAC clones were identified for Sat_258, but more than thirty positive clones were obtained for Satt702. Construction of a contig across the QTL is underway.