Location: Foreign Disease-weed Science Research2013 Annual Report
1a. Objectives (from AD-416):
(1) Identify genes involved in resistance to soybean rust, (2) use the information from the disease resistance studies to provide markers that will be useful to plant breeders for the development of new germplasm with resistance to soybean rust, (3) and to enable collaboration among the nation's premier soybean research scientists with the ultimate goal of improving soybean.
1b. Approach (from AD-416):
The proposed research will be conducted using high throughput virus-induced gene silencing (VIGS) assays to identify genes necessary for resistance towards Asian Soybean Rust (ASR). Genes targeted for silencing will be selected based upon gene mapping data of key soybean resistance genes. Using the VIGS vectors these candidate genes will be silenced, or "turned-off", in soybean plants that display resistance towards select isolates of ASR. Silenced plants will then be evaluated for a breakdown of resistance by challenging the plants with the pathogen and scoring for the development of disease.
3. Progress Report:
To date, six genes known to provide resistance in soybean against the pathogen that causes the disease known as Asian soybean rust have been identified through germplasm screening studies. To confirm the identities of these genes, we are utilizing gene mapping data to design virus-induced gene silencing (VIGS) vectors to target one of these resistance genes, referred to as Rpp1. To further aid in this approach, we have constructed a bacterial artificial chromosome (BAC) library using genomic DNA obtained from a soybean accession containing Rpp1. One BAC clone encompassing a portion of the region where Rpp1 is located has been identified, and efforts are underway to identify additional BAC clones that span the mapped region. The sequence information obtained from the BAC library sequencing should allow us to design Rpp1 VIGS constructs and expression constructs for heterologous expression studies.