Abstract Recent advances in genomics have led to a greater understanding of blackleg disease of canola, caused by the fungus Leptosphaeria maculans. Genome sequences are available for several L. maculans isolates and different Brassica species, and several resistance and avirulence genes, which have a ‘gene for gene’ relationship, have been characterised. Although several pairs of complementary resistance and avirulence genes have been sequenced, the molecular basis of their recognition is unknown. Mechanisms responsible for conferring virulence include amino acid substitutions, gene deletion and Repeat Induced Point mutations of avirulence genes. In some cases, a single avirulence gene is recognised by two resistance genes, and virulence towards each resistance gene is conferred by separate mutations. Furthermore, some avirulence-resistance gene interactions are epistatic over others; for instance, the presence of AvrLm7 (avirulent towards Rlm7) masks the AvrLm3-Rlm3 interaction resulting in isolates phenotypically appearing virulent towards Rlm3 despite having the avirulent form of the AvrLm3 allele. Several high throughput methods, including the ascospore shower technique, are used to characterise cultivar specificity, frequency of avirulence genes, and to detect fungicide sensitivity of fungal populations from stubble. The frequency of virulence in field populations can change rapidly under selection pressure when cultivars with the same resistance genes are sown in subsequent seasons. If there is a high risk of breakdown of a particular source of resistance, canola growers can be advised to sow a different cultivar, thus avoiding an epidemic.

中文翻译：

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了解 Leptosphaeria maculans - Brassica 病理系统及其对疾病管理的影响的进展。

摘要 基因组学的最新进展使人们对由黄斑钩端菌引起的油菜黑胫病有了更深入的了解。几个黄斑斑块菌分离物和不同芸苔属植物的基因组序列是可用的，并且具有“基因对基因”关系的几个抗性和无毒基因已经被表征。尽管已经对几对互补的抗性和无毒基因进行了测序，但它们识别的分子基础尚不清楚。赋予毒力的机制包括氨基酸取代、基因缺失和无毒基因的重复诱导点突变。在某些情况下，单个无毒基因被两个抗性基因识别，对每个抗性基因的毒力由单独的突变赋予。此外，一些无毒抗性基因相互作用是上位性的；例如，AvrLm7 的存在（对 Rlm7 无毒）掩盖了 AvrLm3-Rlm3 相互作用，导致分离株尽管具有 AvrLm3 等位基因的无毒形式，但对 Rlm3 表现出对 Rlm3 的毒性。几种高通量方法，包括子囊孢子喷淋技术，用于表征栽培品种的特异性、无毒基因的频率，并从残茬中检测真菌种群的杀真菌剂敏感性。当具有相同抗性基因的品种在随后的季节播种时，田间种群的毒力频率在选择压力下会迅速变化。如果某个特定抗性来源崩溃的风险很高，可以建议双低油菜籽种植者种植不同的品种，从而避免流行病。