粳稻子预44中稻瘟病数量抗性位点分析

Quantitative Trait Loci Analysis of Rice Blast Resistance in Japonica Rice Variety Ziyu44

稻瘟病是世界范围内影响水稻(Oryza sativa)生产的主要病害。抗稻瘟病基因的发掘和育种利用是控制稻瘟病经济、环保的有效措施。为了揭示云南地方水稻品种子预44广谱持久抗瘟机制,利用江南香糯和子预44杂交构建的F7重组自交群体,采用苗期稻瘟病菌自然诱发接种法,通过调查田间抗瘟性表型数据,结合基因型数据对子预44中的数量抗瘟性位点进行了分析。结果表明,在连锁系数(logarithm of odds,LOD)大于2.0的域值上,共检测出13个QTLs,分别位于第1、2、6、8、12号染色体上。不同位点表型贡献值差异较大,范围为5.8%–21.9%,其中8号染色体上标记RM72–RM404之间的QTLs可解释约61.9%的表型变异,很可能为一个主效抗瘟QTL位点。多个位点的主效和微效抗性相结合可能是子预44持久稻瘟病抗性的分子基础。

Rice blast, caused by Magnaporthe oryzae, is one of the most destructive diseases of rice worldwide. The development and use of resistant cultivars is considered the most economic, effective and environment-friendly method to control this disease. To understand the molecular mechanism of Ziyu44 for durable rice blast resistance, we inoculated 212 F7 recombinant inbred lines（F7RILs） derived from a cross between Ziyu44 and Jiangnan Xiangnuo（JNXN）, a susceptible cultivar, naturally with Magnaporthe oryzae to evaluate rice field leaf-blast resistance. We detected 13 quantitative trait locus（QTLs） on chromosomes 1, 2, 6, 8 and 12. The resulting phenotypic variation due to a single QTL ranged from 5.8% to 21.9%. The QTL on chromosome 8 between simple sequence repeat markers RM72 and RM404 accounted for approximately 61.9% of the total phenotypic variation, which may be a major QTL locus. Durable resistance to rice blast in Ziyu44 may be due to the combination of major and minor resistance on multiple loci.