Submitted to: Crop Science
Publication Type: Abstract Only
Publication Acceptance Date: 1/18/2002
Publication Date: N/A
Technical Abstract: The soybean plant introduction PI 437.654 exhibits broad resistance to soybean cyst nematode (Heterodera glycines). Resistance in PI 437.654 has been linked to two loci: rhg1 on linkage group (LG) G and Rhg4 on LG A2. Previously, molecular markers were used to identify a set of BACs in PI 437.654 corresponding to the Rhg4 locus. These BACs are now being analyzed using BAC end sequencing, restriction enzyme mapping, and hybridization analysis to characterize genes that are involved in the resistance response and their genomic organization. To identify genes located within the resistance region, a suppression substractive hybridization cDNA library constructed from PI 437.654 roots with and without nematode infection was arrayed on high-density filters and screened with BAC sequences. Analysis of the identified clones indicates that a majority of these genes are involved in stress responses. A second root cDNA library enriched for full-length sequences is being used to assist in functional annotation of the Rhg4 region. Gene content and hybridization analysis indicate a large number of duplications at the Rhg4 locus.