Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Zhongshan Biological Breeding Laboratory/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Agricultural College of Yangzhou University, Yangzhou, 225009, People's Republic of China.
Yangzhou Polytechnic College, Yangzhou, 225009, People's Republic of China.
Theor Appl Genet. 2023 Nov 16;136(12):246. doi: 10.1007/s00122-023-04482-z.
qSB12, a major quantitative sheath blight resistance gene originated from rice variety YSBR1 with good breeding potential, was mapped to a 289-Kb region on chromosome 12. Sheath blight (ShB), caused by Rhizoctonia solani kühn, is one of the most serious global rice diseases. Rice resistance to ShB is a typical of quantitative trait controlled by multiple quantitative trait loci (QTLs). Many QTLs for ShB resistance have been reported while only few of them were fine-mapped. In this study, we identified a QTL on chromosome 12, in which the qSB12 resistant allele shows significant ShB resistance, by using 150 BC backcross inbred lines employing the resistant rice variety YSBR1 as the donor and the susceptible variety Lemont (LE) as the recurrent parent. We further fine-mapped qSB12 to a 289-kb region by generating 34 chromosomal segment substitution lines and identified a total of 18 annotated genes as the most likely candidates for qSB12 after analyzing resequencing and transcriptomic data. KEGG analysis suggested that qSB12 might activate secondary metabolites biosynthesis and ROS scavenging system to improve ShB resistance. qSB12 conferred significantly stable resistance in three commercial rice cultivars (NJ9108, NJ5055 and NJ44) in field trials when introduced through marker assisted selection. Under severe ShB disease conditions, qSB12 significantly reduced yield losses by up to 13.5% in the LE background, indicating its great breeding potential. Our results will accelerate the isolation of qSB12 and its utilization in rice breeding programs against ShB.
qSB12 是一个源自水稻品种 YSBR1 的主要数量型叶鞘褐腐病抗性基因，具有良好的育种潜力，被定位到第 12 号染色体上的 289-Kb 区域。叶鞘褐腐病（ShB）是由立枯丝核菌引起的一种全球性水稻病害，是一种典型的由多个数量性状位点（QTL）控制的数量性状。虽然已经报道了许多抗 ShB 的 QTL，但只有少数被精细定位。本研究利用抗性水稻品种 YSBR1 作为供体和感病品种 Lemont（LE）作为轮回亲本，通过 150 个 BC 回交自交系，鉴定到第 12 号染色体上的一个 QTL，该 QTL 的 qSB12 抗性等位基因表现出显著的 ShB 抗性。进一步通过构建 34 个染色体片段替换系将 qSB12 精细定位到 289-Kb 区域，并通过分析重测序和转录组数据，总共鉴定出 18 个注释基因作为 qSB12 的最可能候选基因。KEGG 分析表明，qSB12 可能激活次生代谢物生物合成和 ROS 清除系统，以提高 ShB 抗性。当通过标记辅助选择引入到三个商业水稻品种（NJ9108、NJ5055 和 NJ44）中时，qSB12 在田间试验中表现出显著的稳定抗性。在严重的 ShB 病害条件下，qSB12 在 LE 背景下显著降低了高达 13.5%的产量损失，表明其具有巨大的育种潜力。我们的研究结果将加速 qSB12 的分离及其在水稻抗 ShB 育种计划中的利用。
