Genetic mapping of the Leptosphaeria maculans avirulence gene corresponding to the LepR1 resistance gene of Brassica napus
Genetic mapping of the Leptosphaeria maculans avirulence gene corresponding to the LepR1 resistance gene of Brassica napus
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DOI：
10.1007/s00122-011-1724-3
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发表时间：
2012-02-01
影响因子：
5.4
通讯作者：
Fernando, W. G. Dilantha
中科院分区：
文献类型：
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作者：
Ghanbarnia, Kaveh;Lydiate, Derek J.;Fernando, W. G. Dilantha
AvrLepR 1的真菌病原体Leptosphaeria maculans是无毒基因，对应于芸苔属LepR 1，植物基因控制显性，种族特异性抗这种病原体。利用离体杂交技术，对致病力较强的L.对斑点病毒分离株87-41和无毒力分离株99-56进行了分离，以定位AvrLepR 1基因。在携带LepR 1的卡诺拉品系ddm-12-6s-1上测试了所得F-1后代中的94个的疾病反应。结果表明，99-56对ddm-12 - 6s-1的无毒后代为44个，毒性后代为50个，分离比为1：1，表明99-56对ddm-12-6s-1的无毒为单基因控制。四分体分析也表明分离比为1：1。将AvrLepR 1基因定位于L.与259个SRAP标记、两个克隆的无毒基因AvrLm 1和AvrLm 4 -7以及交配型位点MAT 1相关的分析表明，该基因在斑点病菌中的遗传多样性较高。该遗传图谱由36个连锁群组成，大小从13.1到163.7 cM不等，总跨度为2，076.4 cM。AvrLepR 1基因定位于连锁群4，位于SBG 49 -110和FT 161 -223之间的13.1cM区间。AvrLm 4 -7基因座也位于连锁群4上，靠近但不同于AvrLepR 1基因座，位于FT 161 -223和P1314-300两侧的5.4 cM间隔内。这项工作将使AvrLepR 1的进一步表征和图位克隆成为可能。遗传作图和致病性试验的结合表明AvrLepR 1与L. maculans无毒基因的特征。
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-1 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.