Lee Sais-Beul, Kim Namgyu, Hur Yeon-Jae, Cho Su-Min, Kim Tae-Heon, Lee Ji-Youn, Cho Jun-Hyeon, Lee Jong-Hee, Song You-Chun, Seo Young-Su, Ko Jong-Min, Park Dong-Soo
National Institute of Crop Science, Milyang, 50424, Republic of Korea.
Department of Microbiology, Pusan National University, Pusan, 46241, Republic of Korea.
Rice (N Y). 2019 May 14;12(1):36. doi: 10.1186/s12284-019-0295-9.
Bakanae disease is an important fungal disease caused by Gibberella fujikuroi. Incidence of rice bakanae disease creates serious problems in the foremost rice growing countries, and no rice variety has been found to be completely resistant to this disease. However, breeding rice varieties resistant to bakanae disease may be a cost-saving solution preferable to the application of fungicides. In this study, we aimed to determine the exact position and the candidate gene for qBK1, a major resistant quantitative trait locus (QTLs) for bakanae disease.
The genotypes/phenotypes of recombinants selected from backcrossed recombinant inbred lines of two rice varieties, Shingwang (resistant) and Ilpum (susceptible), indicated that the locus qBK1, conferring resistance to bakanae disease in Shingwang, was delimited to a 35-kb interval delimited by InDel 18 (23.637 Mbp) and InDel 19-14 (23.672 Mbp). Sequence analysis of this 35-kb region revealed four candidate genes, LOC_Os01g41770, LOC_Os01g41780, LOC_Os01g41790, and LOC_Os01g41800. There were many non-synonymous SNPs in LOC_Os01g41770 and the transcript of LOC_Os01g41790 was early terminated in Shingwang, whereas there were no differences in both LOC_Os01g41780 and LOC_Os01g41800 sequences between Ilpum and Shingwang. Expression profiling of the four candidate genes showed the up-regulation of LOC_Os01g41770, LOC_Os01g41780, and LOC_Os01g41790 in Ilpum and of LOC_Os01g41800 in Shingwang after inoculation of G. fujikuroi.
Utilization of marker-assisted selection (MAS) with a precise molecular marker on qBK1 could provide an effective tool for breeding rice varieties resistant to bakanae disease. To our knowledge, this is the first report on fine mapping and candidate gene approaches for identifying the gene for qBK1.
水稻恶苗病是由藤仓赤霉菌引起的一种重要真菌病害。在主要的水稻种植国家，水稻恶苗病的发生造成了严重问题，尚未发现有水稻品种对该病完全抗性。然而，培育抗水稻恶苗病的品种可能是一种比施用杀菌剂更具成本效益的解决方案。在本研究中，我们旨在确定水稻恶苗病主要抗性数量性状位点（QTL）qBK1的确切位置和候选基因。
从两个水稻品种“新光”（抗病）和“日丰”（感病）的回交重组自交系中选择的重组体的基因型/表型表明，赋予“新光”对水稻恶苗病抗性的位点qBK1被定位到由InDel 18（23.637 Mbp）和InDel 19 - 14（23.672 Mbp）界定的35 kb区间内。对该35 kb区域的序列分析揭示了四个候选基因，即LOC_Os01g41770、LOC_Os01g41780、LOC_Os01g41790和LOC_Os01g41800。LOC_Os01g41770中有许多非同义单核苷酸多态性（SNP），且LOC_Os01g41790的转录本在“新光”中提前终止，而“日丰”和“新光”之间LOC_Os01g41780和LOC_Os01g41800的序列没有差异。对这四个候选基因的表达谱分析表明，接种藤仓赤霉菌后，“日丰”中LOC_Os01g41770、LOC_Os01g41780和LOC_Os01g41790上调，“新光”中LOC_Os01g41800上调。
利用针对qBK1的精确分子标记进行标记辅助选择（MAS）可为培育抗水稻恶苗病的水稻品种提供有效工具。据我们所知，这是关于精细定位和候选基因方法以鉴定qBK1基因的首次报道。
