Submitted to: Theoretical and Applied Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/26/2010
Publication Date: 6/1/2010
Publication URL: hdl.handle.net/10113/47268
Citation: Kim, K., Hill, C.B., Hartman, G.L., Hyten, D.L., Hudson, M.E., Diers, B. 2010. Fine Mapping of the Soybean Aphid Resistance Gene Rag2 in Soybean PI 200538. Theoretical and Applied Genetics. 121:599-610. Interpretive Summary: Although the soybean aphid has a short history in the USA, the aphid has caused significant damage and has spread to most soybean growing states since its discovery in the country in 2000. The discovery of biotype diversity of soybean aphid in North America emphasizes the necessity to identify new aphid resistance genes. The soybean plant introduction (PI) 200538 is a promising source of resistance because it shows a high level of resistance to a soybean aphid biotype that can overcomes the soybean aphid resistance gene Rag1 from Dowling. The soybean aphid resistance gene Rag2 was previously mapped from PI 200538. The objective of this study was to fine map the location of Rag2 from PI 200538 through the identification of additional genetic recombinants close to the gene. Fine mapping and high resolution linkage analysis of the Rag2 will facilitate soybean aphid resistance breeding. Marker and candidate gene information identified in this study will be an important resource in marker-assisted selection for aphid resistance and for cloning the gene. This information is useful to soybean geneticists and breeders interested in improving resistance in soybean to the soybean aphid.
Technical Abstract: The discovery of biotype diversity of soybean aphid [SA: Aphis glycines Matsumura] in North America emphasizes the necessity to identify new aphid resistance genes. The soybean [Glycine max (L.) Merr.] plant introduction (PI) 200538 is a promising source of SA resistance because it shows a high level of resistance to a SA biotype that can overcome the SA resistance gene Rag1 from Dowling. The SA resistance gene Rag2 was previously mapped from PI 200538 to a 10 centiMorgan (cM) marker interval on soybean chromosome 13 [formerly linkage group (LG) F]. To fine map Rag2, high resolution linkage analysis was carried out using lines derived from 6,160 F2 plants at different levels of backcrossing that were screened for the presence of recombination in the Rag2 interval with flanking markers. Fifteen single nucleotide polymorphism (SNP) markers and two dominant polymerase chain reaction (PCR) based markers near Rag2 were developed by re-sequencing target intervals and sequence tagged sites (STSs). These efforts resulted in the mapping of Rag2 to a 54 kb interval on the Williams 82 8x assembly (Glyma1). This Williams 82 interval contains seven predicted genes which includes one nucleotide binding site-leucine rich repeat (NBS-LRR) gene. SNP marker and candidate gene information identified in this study will be an important resource in marker-assisted selection (MAS) for aphid resistance and for cloning the gene.