粳稻子预44抗LP11稻瘟病菌基因Pizy6(t)的定位

稻瘟病是世界范围内严重威胁水稻(Oryza sativa)生产可持续发展的主要病害之一,每年造成10%–30%的水稻产量损失。抗瘟水稻品种的培育和育种利用是解决稻瘟病危害最经济有效的方法。对新的致病性菌株进行分离和筛选是定位与克隆抗病新基因及抗病育种的基础。选择分离自不同稻瘟病发生重灾区的单孢菌株,对广谱抗瘟水稻子预44和感病水稻江南香糯进行致病性鉴定,筛选出两材料间致病性差异明显的5个菌株;进一步利用子预44、湘资3150、9311、日本晴、丽江新团黑谷、中花11、TP309和江南香糯8个抗瘟性不同的水稻材料,对筛选的菌株进行致病性鉴定。结果显示,LP11能使广谱抗瘟籼稻湘资3150严重发病,推测其很可能是新进化出来的强致病菌株。利用子预44和江南香糯杂交构建的F2群体进行抗性遗传分析,结果表明子预44对LP11菌株的抗性是由单显性基因控制。利用SSR分子标记和图位克隆方法在子预44中定位了1个抗稻瘟病基因Pizy6(t)。研究结果不仅为抗病相关研究提供了有价值的新菌株,而且为子预44中抗稻瘟病基因Pizy6(t)的克隆奠定了基础。

Mapping of Pizy6(t), a Gene Conferring Resistance to the Rice Blast Strain LP11, in Oryza sativa subsp. japonica Cultivar Ziyu44

Rice blast, caused by Magnaporthe oryzae infection, is one of the major diseases threatening the sustainable development of rice (Oryza sativa) production worldwide. Between 10% and 30% of the annual rice harvest is lost due to infection by the fungus. Development and breeding utilization of rice-resistant resources are considered the most effective and economic means to control rice blast. Isolating new virulent blast strains from the pathotype Oryza is the basis for cloning novel optimal genes resistant to rice blast and rice breeding for disease resistance. In the present study, we isolated and screened blast strains and identified new genes resistant to rice blast. Overall, 5 strains with significantly different pathogenicity between Ziyu44 and Jiangnanxiangnuo (JNXN) were identified. Eight rice varieties, including Ziyu44, Xiangzi3150, 9311, Nipponbare, Lijiangxintuanheigu (LTH), Zhonghua11, JNXN and TP309, were challenged with the 5 blast strains by spray-inoculation at seedling stage. Xiangzi3150, a variety with broad-spectrum blast resistance, showed obvious attacks after inoculation with LP11, so LP11 is probably a newly emerged strong virulent strain. The F₂ progenies derived from the cross between Ziyu44 and JNXN were inoculated with the LP11; genetic analysis and gene mapping indicated that the resistance phenotype of Ziyu44 to LP11 was controlled by a single dominant gene, and the resistance gene Pizy6(t) was located on rice chromosome 6. These results provided valuable blast strains for genetic studies of disease resistance and laid the foundation for Pizy6(t) gene cloning in Ziyu44.