Submitted to: Cereal Rusts and Mildews Conference European and Mediterranean Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/2/1997
Publication Date: N/A
Technical Abstract: Puccinia graminis f.sp. tritici and the disease it causes (black stem rust of wheat) have served as a paradigm for plant pathologists, primarily owing to the importance of the host and the severities of past epidemics. Genetics studies have demonstrated that race-specific resistance in this system fits the gene-for-gene theory. Race-specific resistance is governed dby a resistance gene in the host and a corresponding avirulence gene in th pathogen. Currently, more than 60 different resistance/avirulence gene pairs have been defined for the interaction between wheat and P. graminis f.sp. tritici. In order to understand the mechanisms by which host and parasite interact, we have begun a program to clone and characterize race-specific avirulence genes from P. graminis f.sp. tritici. We have chosen to use map-based cloning to accomplish this objective and have started to develop a genetic map. A mapping population of 81 F2 progeny is currently being used to develop a genetic linkage map of P. graminis f.sp. tritici. To date we have scored and mapped 343 RAPD markers which give 58 linkage groups of 2 or more markers. RAPD markers have been found which are linked to eight single dominant avirulence genes (Avr6, Avr8a, Avr9a, Avr10, Avr21, Avr28, Avr30 and AvrU) and a single recessive avirulence gene (Avr9d). Our goal is to generate a low resolution genetic map of all 18 linkage groups and high resolution maps for the regions surrounding each of these avirulence genes. These RAPD markers will then be used as starting points for creating physical maps and eventually cloning these avirulence genes.