For SCN, two approaches are being continued to characterize the plant-nematode interaction. These are silencing genes in soybean roots that potentially play an important role in the plant-nematode interaction and to determine if BPMV replication can be documented in the syncytium with the ultimate goal of targeting silencing to the feeding site.

In tests with SDS, tests of genes belonging to the ethylene mediated defense response pathway and the jasmonic acid biosynthesis pathway have been repeated. Additional constructs expected to target the same pathways were added to an expanded test.

Approximately 190 plants were screened using the BPMV VIGS system in screens for Asian soybean rust. Candidate gene screening of Rpp3 plants suggested potential for loss-of-resistance phenotype. Three BACs, of which two have been sequenced, have been identified that partially span the Rpp1 resistance locus.

Unexpectedly, tests with soybean mosaic virus revealed that incorporation of the marker gene GUS could alter the avirulence/virulence profile of the virus. Since this gene was being used as a marker gene in studies of the impact of BPMV constructs on soybean mosaic virus pathogenicity, we have elected to use wild type soybean mosaic virus in assays. This has allowed identification of 14 BPMV constructs that may be of interest, although further confirmation of this data is necessary.