背景:纹枯病(ShB),由根瘤菌引起,是最具破坏性的水稻病害之一。开发抗ShB水稻品种代表了管理ShB的最经济,最环保的策略。
结果:为了表征水稻抗ShB的遗传基础,我们对与ShB抗性相关的性状进行了关联研究,即茎秆长度(CL),病变高度(LH),和相对病变高度(RLH)。结合单基因座全基因组扫描和使用2,977,750个单核苷酸多态性的多基因座方法来分析563个水稻种质,我们检测到134、562和75与CL的暗示性关联,LH,和RLH,分别。根据估计的连锁不平衡块,将与RLH相关的相邻信号合并为27个暗示性相关基因座(SAL)。超过44%的检测到的RLH-SAL具有与ShB抗性相关的多个QTL/基因,而其他RLH-SAL是推定的新型ShB抗性基因座。根据生物信息学和单倍型分析,从23个RLH-SAL中筛选出261个ShB抗性推定功能基因。以前报道的一些注释基因编码防御相关和发病相关的蛋白质,表明水稻对ShB的定量抗性是由SA和JA依赖性信号通路介导的。
结论:我们的发现可以改善种质资源的应用以及基于知识的ShB管理和抗ShB水稻品种的选育。
BACKGROUND: Sheath blight (ShB), caused by Rhizoctonia solani Kühn, is one of the most destructive rice diseases. Developing ShB-resistant rice cultivars represents the most economical and environmentally sound strategy for managing ShB.
RESULTS: To characterize the genetic basis for ShB resistance in rice, we conducted association studies for traits related to ShB resistance, namely culm length (CL), lesion height (LH), and relative lesion height (RLH). Combined a single locus genome-wide scan and a multi-locus method using 2,977,750 single-nucleotide polymorphisms to analyse 563 rice accessions, we detected 134, 562, and 75 suggestive associations with CL, LH, and RLH, respectively. The adjacent signals associated with RLH were merged into 27 suggestively associated loci (SALs) based on the estimated linkage disequilibrium blocks. More than 44% of detected RLH-SALs harboured multiple QTLs/genes associated with ShB resistance, while the other RLH-SALs were putative novel ShB resistance loci. A total of 261 ShB resistance putative functional genes were screened from 23 RLH-SALs according to bioinformatics and haplotype analyses. Some of the annotated genes were previously reported to encode defence-related and pathogenesis-related proteins, suggesting that quantitative resistance to ShB in rice is mediated by SA- and JA-dependent signalling pathways.
CONCLUSIONS: Our findings may improve the application of germplasm resources as well as knowledge-based ShB management and the breeding of ShB-resistant rice cultivars.