Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2003
Publication Date: 1/9/2004
Citation: Liu, Z., Faris, J.D., Meinhardt, S., Ali, S., Rasmussen, J., Friesen, T.L. 2004. Genetic and physical mapping of a gene conditioning sensitivity in wheat to a partially purified host-selective toxin by stagonospora nodorum.. Plant and Animal Genome Abstracts. p.185.
Technical Abstract: Stagonospora nodorum is the causal agent of wheat leaf and glume blotch, an economically important disease in many wheat-growing areas throughout the world. Using filtration, ion exchange and gel filtration chromatography, we partially purified a toxin from culture filtrates of isolate Sn2000. This toxin, designated as SnTox1, showed selective action on several different wheat genotypes indicating that it is a host-selective toxin (HST). The ITMI mapping population was evaluated for toxin reaction and used to map the host gene conditioning sensitivity. This gene, designated as Snn1, was genetically mapped to the distal end of chromosome 1BS. The wheat cultivar 'Chinese Spring' (CS) and all CS nullisomic-tetrasomic (NT) lines were sensitive to the toxin, with the exception of N1BT1D. Insensitivity was also observed when the 1B chromosome of CS was substituted by the 1B chromosome of an insensitive accession of Triticum dicoccoides. These results indicate that the toxin sensitivity gene resides on chromosome 1B, and suggest that sensitivity is dominant. A series of 1BS deletion lines were used to physically localize the sensitivity gene. Physical mapping indicated that Snn1 lies within a major gene-rich region on 1BS.