Wang Sheng-Shan, Chang Wei-Bin, Hsieh Ming-Chien, Chen Szu-Yu, Liao Dah-Jing, Liao Ching-Ying, Shen Wei-Chiang, Chen Hong-Hua, Chen Chieh-Yi, Chen Yi-Chia, Lin Yueh-Lin, Tung Chih-Wei, Chen Ruey-Shyang, Chung Chia-Lin
Tainan District Agricultural Research and Extension Station, Ministry of Agriculture, No. 70, Muchang, Xinhua, Tainan, 712009, Taiwan.
Department of Plant Pathology and Microbiology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei City, 106319, Taiwan.
Bot Stud. 2024 Dec 18;65(1):37. doi: 10.1186/s40529-024-00444-w.
Rice blast caused by Pyricularia oryzae is a major threat to rice production worldwide. Tainung 84 (TNG84) is an elite japonica rice cultivar developed through the traditional pedigree method. It has maintained superior blast resistance since its release in 2010. This study aimed to investigate the genetic factors underlying the durable resistance of TNG84 in Taiwan.
Quantitative trait locus (QTL) mapping was conducted using 122 F individuals and F families derived from the cross of TNG84 and a susceptible japonica cultivar Tainan 11 (TN11). Using 733 single nucleotide polymorphisms (SNPs) obtained through genotyping-by-sequencing and three P. oryzae isolates (D41-2, 12CY-MS1-2, and 12YL-TT4-1) belonging to different physiological races and Pot2 lineages, a major QTL was identified in the region of 52-54 cM (9.54-15.16 Mb) on chromosome 12. Fine-mapping using 21 F recombinants delimited the QTL to a 140.4-kb region (10.78 to 10.93 Mb) containing the known resistance gene Ptr. Sequencing analysis indicated that TNG84 carries the resistant PtrA allele and TN11 carries the susceptible PtrD allele. Investigation of the Ptr haplotypes in 41 local japonica rice cultivars revealed that eight PtrA-containing cultivars (19.5%) consistently exhibited good field resistance in Taiwan from 2008 to 2024. Subsequently, a few F lines (P026, P044, P092, and P167) lacking the resistant Ptr allele were observed to exhibit a resistant phenotype against P. oryzae 12YL-TT4-1-lab. Trait-marker association analyses using eight F homozygous recombinants, 378 BCF from P044 backcrossed to TN11, and 180 BCF from P092 backcrossed to TN11, identified Piz-t on chromosome 6 and a new QTL located between 3.3 Mb and 4.4 Mb on chromosome 12 (designated as qBR12_3.3-4.4). Analysis of 12 selected BCF lines derived from P044 demonstrated that in the absence of Ptr and Piz-t, qBR12_3.3-4.4 alone reduced the disease severity index from approximately 6.3 to 3.9.
PtrA is likely the primary gene responsible for the broad-spectrum and durable resistance of TNG84. Piz-t confers narrow-spectrum resistance, while qBR12_3.3-4.4 contributes partial resistance. The discovery of qBR12_3.3-4.4 has provided a new source of blast resistance, and the markers developed in this study can be utilized in future breeding programs.
由稻瘟病菌引起的稻瘟病是全球水稻生产的主要威胁。台农84（TNG84）是通过传统系谱法培育的优良粳稻品种。自2010年发布以来，它一直保持着优异的抗瘟性。本研究旨在探究TNG84在台湾具有持久抗性的遗传因素。
利用从TNG84与感病粳稻品种台南11（TN11）杂交获得的122个F个体和F家系进行数量性状位点（QTL）定位。通过简化基因组测序获得733个单核苷酸多态性（SNP），并使用属于不同生理小种和Pot2谱系的3个稻瘟病菌株（D41 - 2、12CY - MS1 - 2和12YL - TT4 - 1），在第12号染色体52 - 54 cM（9.54 - 15.16 Mb）区域鉴定到一个主要QTL。利用21个F重组体进行精细定位，将该QTL定位到一个包含已知抗性基因Ptr的140.4 kb区域（10.78至10.93 Mb）。测序分析表明，TNG84携带抗性PtrA等位基因，TN11携带感病PtrD等位基因。对41个当地粳稻品种的Ptr单倍型进行调查发现，8个含有PtrA的品种（19.5%）在2008年至2024年期间在台湾田间始终表现出良好的抗性。随后，观察到一些缺乏抗性Ptr等位基因的F株系（P026、P044、P092和P167）对稻瘟病菌12YL - TT4 - 1 - lab表现出抗性表型。利用8个F纯合重组体、378个P044与TN11回交的BCF以及180个P092与TN11回交的BCF进行性状 - 标记关联分析，在第6号染色体上鉴定到Piz - t以及位于第12号染色体3.3 Mb和4.4 Mb之间的一个新QTL（命名为qBR12_3.3 - 4.4）。对从P044衍生的12个选定BCF株系的分析表明，在没有Ptr和Piz - t的情况下，单独的qBR12_3.3 - 4.4可将病情严重指数从约6.3降低到3.9。
PtrA可能是TNG84广谱和持久抗性的主要基因。Piz - t赋予窄谱抗性，而qBR12_3.3 - 4.4贡献部分抗性。qBR12_3.3 - 4.4的发现提供了一个新抗瘟性来源，本研究开发的标记可用于未来的育种计划。
