|Goodwin, Stephen - Steve|
Submitted to: International Septoria Stagonospora Workshop
Publication Type: Abstract only
Publication Acceptance Date: 7/26/2008
Publication Date: 8/18/2008
Citation: Goodwin, S.B., Cavaletto, J.R., Lowe, I., Thompson, I.A., Xu, S.X., Adhikari, T.B., Dubcovsky, J. 2008. Validation of a new map location for the Stb3 gene for resistance to septoria tritici blotch in wheat. International Septoria Stagonospora Workshop. Available at: http://www.path.ethz.ch/news/conferences/Mycosphaerella_Ascona_2007/00022_posterabstract.pds Interpretive Summary:
Technical Abstract: Septoria tritici blotch (STB) caused by Mycosphaerella graminicola is one of the most important diseases of wheat worldwide. In North America where chemical controls are not economically viable, host resistance is the only means of disease management. The Stb3 gene provides a high level of resistance but has not been used extensively in breeding programs. This changed during 2004 when Stb3 was mapped to the short arm of chromosome 6D. However, that location was based on linkage to a single microsatellite marker and was not validated in independent progeny sets. To identify additional markers linked to Stb3, 12 microsatellite loci near the published location on chromosome 6DS were tested for polymorphism between the parents of the original mapping population. Five of these loci were polymorphic, but none was linked to Stb3. Subsequent tests of 251 microsatellite loci covering all 21 wheat chromosomes plus Target Region Amplification Polymorphism (TRAP) marker analysis identified linkages on chromosome 7A. Ten loci on chromosome 7A were polymorphic and formed a linkage block with Stb3 and a TRAP locus among 54 loci on this chromosome that were tested in total. Analysis of deletion lines placed the location of Stb3 on the short arm near microsatellite locus Xwmc83. This map location was validated in two additional progeny sets. Seedlings were tested for molecular marker genotype and for resistance by inoculation with an Australian isolate of M. graminicola. Results of the genotypic testing were done in California and kept in a sealed envelope until the phenotypic tests were completed in Indiana. Comparison of the two data sets revealed an almost perfect correspondence, validating the new map location of Stb3 on the short arm of wheat chromosome 7A.