|Goodwin, Stephen - Steve|
|Van Der Lee, Theo|
Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/23/1999
Publication Date: N/A
Technical Abstract: We have developed a crossing protocol to obtain a mapping population of M. graminicola, the causal agent of septoria tritici leaf blotch disease of wheat. The parental strains are highly contrasting for their avirulences towards a number of wheat cultivars, characteristics that appear to be under monogenic control. Progenies could therefore be used to map avirulence- and MAT-loci and to identify linked markers in order to start map-based cloning strategies to isolate these genes. A F1 progeny of IPO323 [avirulent, MAT1-1] and IPO94269 [virulent, MAT1-2] was isolated and 68 isolates were used to construct a linkage map using AFLP and RAPD technology. Using a LOD threshold value of 4, 410 of the 439 markers showed linkage to at least three other markers, eventually resulting in 26 linkage groups. In addition, we conducted bulked segregant analyses, which resulted in two additional markers that perfectly linked with the avirulence locus. AFLP markers that mapped on the same linkage group as the avirulence locus were used as probes to identify the chromosome on pulsed-field gel electrophoresis [PFGE] blots. Similarly, a heterologous MAT probe was used to identify the chromosome carrying the MAT locus. Although the map indicated that both genes were located on small linkage group, these probes hybridized to much larger chromosomes on PFGE filters, which was also confirmed by marker-derived SCARS on chromosome bands excised from PFGE gels. This strategy is used to relate linkage groups to specific chromosomes in order to establish a physical map of the genome.