W440 Development of Aphid Resistant Germplasm Through a Combination of Germplasm and Genomic Resources

Date: Sunday, January 15, 2012
Time: 9:00 AM
Room: Pacific Salon 1
Brian Diers , University of Illinois, Urbana, IL
Ki-Seung Kim , University of Illinois, Urbana, IL
Jianping Wang , University of Florida, Gainesville, FL
Carolyn Bonin , University of Illinois, Urbana, IL
Curtis B Hill , University of Illinois, Urbana, IL
Glen L Hartman , USDA-ARS, Urbana, IL
Matthew Hudson , University of Illinois, Urbana, IL
Soybean aphid (Aphis glycines Matsumura) was first discovered in North America in 2000 and has become an important soybean [Glycine max (L.) Merr.] pest. After this discovery, sources of resistance were identified from the soybean germplasm collection and the major resistance genes Rag1 and Rag2 were mapped. This mapping resulted in the identification of simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers linked to the resistance genes. These markers have been used in marker-assisted selection resulting in the release of aphid resistant cultivars from both the private and public sector. Rag1 and Rag2 were fine mapped to develop markers closely linked to the genes for use in marker-assisted selection and to develop resources needed for cloning each gene. Based on the Williams 82 genome sequence, Rag1 was mapped to a 115 kb interval that contained two NBS LRR candidate genes and Rag2 was mapped to a 54 kb interval containing one NBS LRR gene. The Rag1 interval was cloned and sequenced from Dowling, which revealed that this genotype has two NBS LRR genes and one of these genes was not in the Williams 82 interval sequence. Both candidate genes from Dowling were transformed into a susceptible genotype for functional validation. Research is currently focused on searching for new aphid resistance genes from the soybean germplasm collection. Populations segregating for resistance genes from 26 new aphid resistance sources have been tested and no new resistance loci have been uncovered.