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United States Department of Agriculture

Agricultural Research Service

Research Project: EQTL ANALYSIS IN SOYBEAN POPULATIONS TO ELUCIDATE GENETIC ARCHITECTURE OF HOST RESPONSE TO INFECTION BY SCLEROTINIA SCLEROTIORUM
2010 Annual Report


1a.Objectives (from AD-416)
This research is being conducted to increase the level of resistance to Sclerotinia sclerotiorum in soybean cultivars and to develop and evaluate improved disease control and resistance options for soybean producers.


1b.Approach (from AD-416)
This plan of work makes use of DNA markers and marker-assisted selection to identify and manipulate chromosomal regions that are associated with smaller lesions size when soybeans are infected with S. sclerotiorum. We are combining multiple QTL identified by the DNA marker genotypes into individual homozygous F5-serived soybean lines to increase overall resistance to the fungus. We also are evaluating different transgenic approaches that may either confer resistance to the fungus (via a lytic peptide expressed in the transgenic plants that destroys the fungus) or may allow the use of effective chemical control measures against Sclerotinia as well as other fungal and bacterial pathogens and soybean cyst nematode.


3.Progress Report

This project was initiated on June 1, 2008, research is ongoing, and the overall objective is to increase the level of resistance to Sclerotinia sclerotiorum in soybean cultivars and to develop and evaluate improved disease control and resistance options for soybean producers. ADODR monitoring activities to evaluate research progress included phone calls, meetings with the cooperator, and an annual meeting held each year in January.

Enhancing Sclerotinia resistance in soybean: Management strategies for Sclerotinia stem rot or white mold of soybean have limitations. Crop culture modifications often compromise high yield, fungicides add to production costs, and resistance found to date is partial, multigenic, and complex. This project brings together expertise and results from identification of genes involved in resistance to Sclerotinia sclerotiorum in soybean and basic research on plant defense mechanisms in response to fungal pathogen infection. The LysM-encoding genes are known to be involved in reaction to fungal infection, and some of these have been mapped to regions in the soybean genome previously identified as quantitative trait loci (QTL) for resistance to sclerotinia stem rot. This project is focused on the LysM domain encoding genes and mapping them in two soybean recombinant inbred line populations that were used previously to identify quantitative trait loci for resistance to sclerotinia stem rot. We are correlating the map locations of the LysM-encoding genes with those of the identified QTL. In addition, we are developing polymorphic SNP markers for the LysM genes that map close to existing QTL. These genes represent promising candidate genes that would explain the resistance to white mold in selected cultivars. Genetic markers developed against these LysM-domain encoding genes should be useful for molecular assisted selection to move the favorable QTL loci into elite lines of soybean.


Last Modified: 12/19/2014
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