ARS | Publication request: Targeted Sequencing of the Rpp2 Asian Soybean Rust Resistance Locus

Submitted to: Biennial Conference on Molecular and Cellular Biology of the Soybean
Publication Type: Abstract Only
Publication Acceptance Date: July 20, 2008
Publication Date: N/A

Technical Abstract: Outbreaks of Asian Soybean Rust (ASR, Phakopsora pachyrhizi) have occurred in all major soybean producing countries including the United States. Thus far, only five genes (Rpp1, Rpp2, Rpp3, Rpp4 and Rpp5) conferring resistance to ASR have been identified. In previous work, Silva et al. (2008) mapped the Rpp2 resistance gene to a ~10 cM region on soybean linkage group J, between SSR markers Sat_255 and Satt620. Six SSR markers from this region were used to screen the Iowa State University/USDA-ARS ‘Williams 82’ BAC library. BAC-end sequencing and additional library screening using BAC-end derived primers resulted in three BAC contigs. Based on the presence of resistance gene (R-gene) homologs within BAC-ends sequences, eight BACs were chosen for full sequencing. Sequencing of these regions identified three clusters of disease resistance genes containing a total of 22 candidate R-genes. The candidate genes had greatest similarity to NBS/LRRs (nucleotide binding site/leucine rich repeats) previously identified from soybean and apple scab resistance RLPs (receptor-like proteins). Ten SSR markers were developed from the sequenced regions surrounding the candidate genes and currently being used to further delineate the location of Rpp2.