Combined Approaches Toward Mapping and Cloning of Powdery Mildew Resistance Gene QPm.tut-4A Introgresed to Bread Wheat from T. militinae

Recently, introgression from the tetraploid wheat Triticum militinae to hexaploid wheat cv Tähti resulted in improved powdery mildew resistance. The resistance locus was mapped on distal end of 4AL chromosomal arm to the region of approximately 10 cM delimited by wmc232 and wmc313 markers and assigned as QPm-tut-4A. In the original mapping population from a cross of Tähti and resistant introgressive line 8.1 the region comprises 12 additional markers. However, an order of the markers could not be resolved using 1200 haplotypes. To overcome the obstruction a combinations of physical map, radiation hybrid panel with 600 lines, collinearity study and three additional recombination mapping populations comprising 1200 lines and over 600 markers were employed. Using these resources the QPm-tut-4A gene was delimited in 0.3 cM region flanked with gpw356 and gpw3079 markers. The region was anchored to distal part of the rice chromosomal arm 6S. Three BAC contigs from 4AL specific physical map comprising 296 BAC clones were identified for the region. 488 BAC ends were sequenced. Two of them were mapped to the QPm-tut-4A region verifying the contigs identity. The physical map, radiation hybrid lines, collinear genes and markers and the remaining BAC-end sequences will be used for the QPm-tut-4A region saturation the gene cloning. This work has been supported by the Czech Science Foundation (521/08/1629), by the Ministry of Education, Youth and Sports of the Czech Republic and the European Regional Development Fund (Operational Programme No. CZ.1.05/2.1.00/01.0007), Internal Grant Agency PrF-2011-003 and by Estonian Ministry of Agriculture.