Achieving the objectives:
• In the area of Asian soybean rust research, 7 VIGS constructs designed to silence hub genes for Rpp2 resistance were tested; none showed a reduction in resistance, suggesting that either the genes were not sufficiently silenced or they do not play a role in Rpp2 mediated resistance. Work on Rpp3 is nearly complete. A VIGS construct designed to silence 5 candidate TIR-NBS-LRR resistance genes on chromosome 6 yielded a loss of resistance phenotype. In order to determine the genes in the Rpp1 locus, a BAC library of the DNA region was isolated and sequenced, revealing 3 candidate NBS-LRR genes. VIGS is being done to silence these genes.
• Transgenic plants that over express selected transcription factor genes (WRKY36 and MYB84) thought to be important for soybean disease resistance are being progressed to expression testing of the transgenes in the plants.
• Work continues in screening genes for responses in white mold, or Sclerotinia sclerotiorum infection. Several hub genes are being tested in the variety Traff, which has tolerance to BPMV and a predictable reaction to S. sclerotiorum. Three genes were shown to enhance resistance when silenced. Additional tests are underway, some of which are promising, particularly for NADPH oxidase genes. Classes of genes that are either upregulated or down regulated in susceptible versus resistant interactions were identified.
Not achieving the objectives:
• None at this time.