1 Institute of Plant Genetics, Breeding and Biotechnology, University of Life Sciences in Lublin, 20-950 Lublin, Poland.
2 Polish Academy of Sciences Botanical Garden, Center for Biological Diversity Conservation in Powsin, 02-973 Warsaw, Poland.
Plant Dis. 2019 May;103(5):832-840. doi: 10.1094/PDIS-06-18-1045-RE. Epub 2019 Feb 25.
Crown rust is the most widespread and damaging disease of oat ( species). Genetic resistance to the pathogen is the preferred method for crop protection but widespread deployment of limited numbers of major effect genes has promoted the rapid emergence and spread of pathogen races that are able to overcome these genes. Combining genes with even partial resistance may help develop durable cultivars that are less vulnerable to changes in pathogen virulence. Partial resistance is expected to be relatively common in populations of wild species where constant pathogen pressure encourages diversity in host resistance mechanisms, but it may be discarded in conventional screens for major gene resistance. Here, we used a detached leaf assay to detect resistance to the crown rust pathogen, Cda. f. sp. , in previously uncharacterized collections of the hexaploid wild oat relative made by the Polish National Centre for Plant Genetic Resources. Many of the accessions were collected in Morocco, the center of diversity for the genus. The detached leaf assessment allowed individual plants to be challenged with multiple pathotypes and their responses compared with 34 known differentials. Broad-spectrum resistance was identified within accession PL 51855, which behaved as a single major locus on crossing to three cultivars. The locus provided resistance to over 50 rust pathotypes, a greater range than seen for any of the known host resistance () genes. Strong resistance was identified in other accessions, and heterogeneity in response within accessions was common. Several accessions show multiple partial resistance responses that may be of value for developing durable resistance in cultivars. Because the sources of resistance in all but two differential lines were collected outside of Morocco, resistance in all accessions tested here are potentially novel. This study demonstrates that diversity within accessions collected in Morocco could be a very valuable source of resistance to crown rust, and it provides new germplasm for use in resistance breeding programs. Detached leaf assessment provides a valuable first step in the identification of promising candidates in complex gene bank accessions.
冠锈病是燕麦（种）最广泛和最具破坏性的疾病。对病原体的遗传抗性是作物保护的首选方法，但广泛部署数量有限的主要效应基因促进了能够克服这些基因的病原体小种的快速出现和传播。将具有甚至部分抗性的基因结合起来，可能有助于开发对病原体毒力变化不太敏感的持久品种。部分抗性预计在野生种群体中较为常见，在这些群体中，持续的病原体压力鼓励宿主抗性机制的多样性，但在常规的主要基因抗性筛选中可能会被淘汰。在这里，我们使用离体叶片分析来检测对六倍体野生燕麦相关种的冠锈病病原体 Cda. f. sp. 的抗性，该分析由波兰国家植物遗传资源中心进行。许多材料是在摩洛哥收集的，摩洛哥是该属的多样性中心。离体叶片评估允许对单个植物进行多种致病型的挑战，并将其反应与 34 个已知的鉴别品种进行比较。在 PL 51855 号材料中发现了广谱抗性，该材料在与三个品种杂交时表现为单个主基因座。该基因座为超过 50 个锈菌致病型提供了抗性，比任何已知的宿主抗性（）基因都要广泛。在其他材料中也发现了强抗性，材料内的反应异质性很常见。一些材料显示出多种部分抗性反应，这可能对在品种中开发持久抗性具有价值。由于除了两个鉴别品种之外的所有鉴别品种的抗性来源都是在摩洛哥以外收集的，因此这里测试的所有材料的抗性都是潜在的新的。本研究表明，在摩洛哥收集的材料的种内多样性可能是对抗冠锈病的非常有价值的来源，并为抗性育种计划提供了新的种质资源。离体叶片评估为在复杂的基因库材料中鉴定有前途的候选材料提供了一个有价值的第一步。
