Plant Biotechnology, Department of Biology, ETH Zurich (Swiss Federal Institute of Technology) Zurich, Switzerland.
International Rice Research Institute Los Banos, Philippines.
Front Plant Sci. 2014 Oct 2;5:505. doi: 10.3389/fpls.2014.00505. eCollection 2014.
Rice is a major cereal crop that contributes significantly to global food security. Biotic stresses, including the rice blast fungus, cause severe yield losses that significantly impair rice production worldwide. The rapid genetic evolution of the fungus often overcomes the resistance conferred by major genes after a few years of intensive agricultural use. Therefore, resistance breeding requires continuous efforts of enriching the reservoir of resistance genes/alleles to effectively tackle the disease. Seed banks represent a rich stock of genetic diversity, however, they are still under-explored for identifying novel genes and/or their functional alleles. We conducted a large-scale screen for new rice blast resistance sources in 4246 geographically diverse rice accessions originating from 13 major rice-growing countries. The accessions were selected from a total collection of over 120,000 accessions based on their annotated rice blast resistance information in the International Rice Genebank. A two-step resistance screening protocol was used involving natural infection in a rice uniform blast nursery and subsequent artificial infections with five single rice blast isolates. The nursery-resistant accessions showed varied disease responses when infected with single isolates, suggesting the presence of diverse resistance genes/alleles in this accession collection. In addition, 289 accessions showed broad-spectrum resistance against all five single rice blast isolates. The selected resistant accessions were genotyped for the presence of the Pi2 resistance gene, thereby identifying potential accessions for isolation of allelic variants of this blast resistance gene. Together, the accession collection with broad spectrum and isolate specific blast resistance represent the core material for isolation of previously unknown blast resistance genes and/or their allelic variants that can be deployed in rice breeding programs.
水稻是一种主要的谷类作物，对全球粮食安全有重要贡献。生物胁迫，包括稻瘟病菌，会导致严重的产量损失，严重影响全球的水稻生产。真菌的快速遗传进化常常在几年的密集农业使用后克服了由主要基因赋予的抗性。因此，抗性育种需要不断努力丰富抗性基因/等位基因的储备，以有效应对疾病。种子库代表了丰富的遗传多样性，但它们在鉴定新基因和/或其功能等位基因方面的研究仍不充分。我们在来自 13 个主要水稻种植国家的 4246 个地理上多样化的水稻品种中进行了大规模筛选新的稻瘟病抗性资源。这些品种是根据国际水稻基因库中对其稻瘟病抗性的注释信息，从超过 12 万份品种总集中选择的。采用两步抗性筛选方案，包括在水稻均匀稻瘟病苗圃中进行自然感染，随后用五个单稻瘟病分离物进行人工感染。苗圃抗性品种在感染单个分离物时表现出不同的疾病反应，这表明该品种集中存在多种抗性基因/等位基因。此外，289 个品种对所有五个单稻瘟病分离物表现出广谱抗性。选择的抗性品种进行 Pi2 抗性基因的存在进行基因型分析，从而鉴定出该稻瘟病抗性基因的等位变体的潜在品种。总的来说，具有广谱和分离物特异性稻瘟病抗性的品种集代表了分离以前未知的稻瘟病抗性基因和/或其等位变体的核心材料，这些基因和/或等位变体可以在水稻育种计划中得到应用。
