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- Title
Genetic mapping of the Leptosphaeria maculans avirulence gene corresponding to the LepR1 resistance gene of Brassica napus.
- Authors
Ghanbarnia, Kaveh; Lydiate, Derek; Rimmer, S.; Li, Genyi; Kutcher, H.; Larkan, Nicholas; McVetty, Peter; Fernando, W.
- Abstract
AvrLepR1 of the fungal pathogen Leptosphaeria maculans is the avirulence gene that corresponds to Brassica LepR1, a plant gene controlling dominant, race-specific resistance to this pathogen. An in vitro cross between the virulent L. maculans isolate, 87-41, and the avirulent isolate, 99-56, was performed in order to map the AvrLepR1 gene. The disease reactions of the 94 of the resulting F progenies were tested on the canola line ddm-12-6s-1, which carries LepR1. There were 44 avirulent progenies and 50 virulent progenies suggesting a 1:1 segregation ratio and that the avirulence of 99-56 on ddm-12-6s-1 is controlled by a single gene. Tetrad analysis also indicated a 1:1 segregation ratio. The AvrLepR1 gene was positioned on a genetic map of L. maculans relative to 259 sequence-related amplified polymorphism (SRAP) markers, two cloned avirulence genes ( AvrLm1 and AvrLm4- 7) and the mating type locus ( MAT1). The genetic map consisted of 36 linkage groups, ranging in size from 13.1 to 163.7 cM, and spanned a total of 2,076.4 cM. The AvrLepR1 locus was mapped to linkage group 4, in the 13.1 cM interval flanked by the SRAP markers SBG49-110 and FT161-223. The AvrLm4- 7 locus was also positioned on linkage group 4, close to but distinct from the AvrLepR1 locus, in the 5.4 cM interval flanked by FT161-223 and P1314-300. This work will make possible the further characterization and map-based cloning of AvrLepR1. A combination of genetic mapping and pathogenicity tests demonstrated that AvrLepR1 is different from each of the L. maculans avirulence genes that have been characterized previously.
- Subjects
PLANT gene mapping; LEPTOSPHAERIA; RAPESEED; GENETIC regulation in plants; LOCUS (Genetics); GENETIC polymorphisms; PLANT growth; PLANT genetics
- Publication
Theoretical & Applied Genetics, 2012, Vol 124, Issue 3, p505
- ISSN
0040-5752
- Publication type
Article
- DOI
10.1007/s00122-011-1724-3