|Nilmalgoda, Sasanda - CLEMSON UNITERSITY|
|Knap, Halina - CLEMSON UNIVERSITY|
Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: March 3, 2000
Publication Date: N/A
Technical Abstract: Soybean cyst nematode (SCN) is the most serious pest of soybeans in the US. The most desirable control method is the use of soybean cultivars having SCN resistance genes. The SCN resistance gene, Rhg4, is located near the I locus controlling seed coat color. From published sequence of the I locus, we developed a PCR marker. In addition, the molecular marker, pBLT65, is close to Rhg4. Both markers were used to screen a 'Williams 82' (susceptible) Bacterial Artificial Chromosome (BAC) library and identified one 150kb BAC. SSR markers and a subclone library were developed from this BAC. Subclones from the BAC were sequenced: 1) to identify genes in this region, and 2) to develop additional markers to use in finding the same region in resistant genotypes. These markers identified 87 BACs from a PI 437.654 (resistant) BAC library. Restriction fragment analysis using FPC (fingerprinted contigs) software at several stringency levels assigned BACs to contigs. RFLP markers pBLT65 and the I locus were assigned by FPC at all stringency levels to separate contigs. However, connection of contigs containing these markers was confirmed by PCR primers developed from BAC-end sequencing. Because these primers did not amplify a product from the Williams 82 BAC, and because the physical distance between pBLT65 and the I locus marker is greater in PI 437.654 than in Williams 82, we are investigating the possibility that there may be an insertion in PI 437.654 relative to Williams 82.