Institute of Plant Genetics, Breeding and Biotechnology, University of Life Sciences in Lublin, Lublin, Poland.
Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, UK.
Plant Dis. 2018 Dec;102(12):2616-2624. doi: 10.1094/PDIS-03-18-0528-RE. Epub 2018 Oct 18.
Crown rust, caused by Puccinia coronata f. sp. avenae, is the most widespread and harmful fungal disease of oat. The best defense against the pathogen is use of cultivars with genetic resistance, which is effective, economic, and an environmentally friendly alternative to chemical control. However, the continuous evolution of the pathogen can rapidly overcome major gene resistance, creating an urgent need to identify new sources. Wild oat accessions have already proven to be valuable donors of many resistance genes, but the weed species Avena fatua remains underexploited. Its abundance across multiple environments and the frequent occurrence of herbicide-resistant populations demonstrate its ready ability to adapt to biotic and abiotic stresses; yet, surprisingly, there are no extensive studies which describe crown rust resistance occurrence in gene bank stocks of A. fatua. In this study, 204 accessions of A. fatua maintained in the collections of the United States Department of Agriculture (USDA) and Polish National Centre for Plant Genetic Resources were evaluated at the seedling stage for crown rust reaction using host-pathogen tests with five highly diverse and virulent races of P. coronata. Of tested genotypes, 85% showed a heterogeneous infection pattern, while 61% were susceptible or moderately susceptible to all races. Of the 79 resistant A. fatua accessions, seedling resistance to at least two P. coronata isolates was recognized within 19 accessions, with 13 displaying a homogeneously resistant phenotype to one or two races. Accessions showing multiple single seedling resistance to three or four isolates were observed. Based on the seedling reaction to isolates used in the study, 18 infection profiles (IP) were determined. Using UPGMA clustering, resistant accessions were divided into six main clusters encompassing samples with similar IPs. Twelve of 18 patterns allowed us to postulate the likely presence of novel crown rust resistance genes, whose origin was predominantly from Kenya or Egypt. Future work will clarify the genetic basis of the resistances observed here, as well as confirm their potential utility in breeding resistant oat cultivars.
冠锈病，由禾冠柄锈菌引起，是燕麦最广泛和有害的真菌病害。防治病原菌的最佳方法是使用具有遗传抗性的品种，这种方法有效、经济且对环境友好，是化学防治的替代方法。然而，病原菌的持续进化可以迅速克服主要基因抗性，因此迫切需要鉴定新的来源。野生燕麦品系已被证明是许多抗性基因的宝贵供体，但杂草物种野燕麦仍未得到充分利用。它在多种环境中的丰富度和经常出现的抗除草剂种群表明它有能力适应生物和非生物胁迫；然而，令人惊讶的是，目前还没有广泛的研究描述基因库中野燕麦品系对冠锈病的抗性。在这项研究中，使用宿主-病原体测试，对保存在美国农业部（USDA）和波兰国家植物遗传资源中心收藏中的 204 份野燕麦品系进行了幼苗期冠锈病反应评估，该测试使用了 5 个高度多样化和毒力强的禾冠柄锈菌菌株。在测试的基因型中，85%表现出异质感染模式，而 61%对所有菌株均表现为感病或中度感病。在 79 份抗野燕麦品系中，有 19 份品系至少对 2 个禾冠柄锈菌分离物表现出抗性，其中 13 份品系对 1 或 2 个菌株表现出均一抗性表型。观察到对三个或四个分离物具有多种单株幼苗抗性的品系。根据对研究中使用的分离物的幼苗反应，确定了 18 种感染谱（IP）。使用 UPGMA 聚类，将抗性品系分为 6 个主要聚类，包含具有相似 IP 的样本。在 18 种模式中的 12 种模式，使我们可以推测出可能存在的新的冠锈病抗性基因，这些基因的来源主要来自肯尼亚或埃及。未来的工作将阐明这里观察到的抗性的遗传基础，并确认它们在培育抗燕麦品种中的潜在用途。
