Hayashi Keiko, Yoshida Tomofumi, Suzuki Tarou, Kuroda Masaharu, Hayano-Saito Yuriko
Institute of Agrobiological Sciences, NARO, Kan-nondai, Tsukuba, Ibaraki 305-8604, Japan.
Mountainous Region Agricultural Institute, Aichi Agricultural Research Center, Inabu, Toyota, Aichi 441-2513, Japan.
Breed Sci. 2025 Apr;75(2):139-146. doi: 10.1270/jsbbs.24059. Epub 2025 Mar 26.
Resistance breeding for rice blast is an economic strategy for protecting rice crops against this disease. Genes with nucleotide-binding site leucine-rich repeat (NBS-LRR) structures are known to contribute to disease resistance. Here, we identified a candidate resistance gene, named (t), associated with leaf and panicle blasts in an introgression line carrying the chromosome 4 segment of wild rice ( Griff.) backcrossed with the cultivar 'Nipponbare' ( L.). Mapping analysis based on leaf blast severity confirmed that (t) was localized in the 177-kb NBS-LRR cluster region. To identify the (t) sequence, mutant lines were generated by knocking out a candidate NBS-LRR gene in a homozygous line carrying (t), M18, using CRISPR/Cas9-mediated genome editing. Leaf blast resistance was lost in the mutant lines lacking the corresponding Os04g0620950 N-terminal sequence of the M18 line. The result suggested that the counterpart NBS-LRR gene in the M18 line is involved in resistance to leaf blast. (t) showed homology to in the resistant cultivar 'Kahei', and an NBS-LRR gene in the resistant cultivar 'Mine-haruka' carrying (t). These results suggest that the NBS-LRR gene is a candidate gene of (t) and is present on the long arm of chromosome 4.
水稻稻瘟病抗性育种是保护水稻作物免受这种病害的一种经济策略。已知具有核苷酸结合位点富含亮氨酸重复序列（NBS-LRR）结构的基因有助于抗病性。在此，我们在一个携带野生稻（Griff.）第4染色体片段并与品种‘日本晴’（L.）回交的渐渗系中鉴定出一个与叶瘟和穗瘟相关的候选抗性基因，命名为（t）。基于叶瘟严重程度的定位分析证实（t）位于177 kb的NBS-LRR簇区域。为了鉴定（t）序列，我们利用CRISPR/Cas9介导的基因组编辑技术，通过敲除携带（t）的纯合系M18中的一个候选NBS-LRR基因来产生突变系。在缺乏M18系相应Os04g0620950 N端序列的突变系中，叶瘟抗性丧失。结果表明，M18系中的对应NBS-LRR基因参与了对叶瘟的抗性。（t）与抗性品种‘卡黑’以及携带（t）的抗性品种‘Mine-haruka’中的 具有同源性。这些结果表明，该NBS-LRR基因是（t）的候选基因，位于第4染色体长臂上。
