水稻抗白叶枯病种质资源筛选及抗性基因鉴定

Germplasm resource screening of resistance against bacterial blight and identification of resistance gene in rice

【目的】筛选抗水稻白叶枯病Ⅴ和Ⅸ型菌的水稻品种。【方法】以97个收集自热带亚热带地区的抗褐飞虱水稻品种为待测样品,水稻白叶枯病Ⅴ、Ⅸ型菌为菌种。用剪叶接种法鉴定水稻在苗期和成株期的抗白叶枯病能力并划分抗性等级。对抗性表现优异的品种构建定位群体,并进行基因定位及克隆。【结果】筛选出苗期抗Ⅴ型菌的水稻品种20个,成株期8个,2个时期均表现为中抗及以上的品种4个;苗期抗Ⅸ型菌的水稻品种34个,成株期9个,2个时期均表现为中抗及以上的品种1个。其中,供试水稻品种‘BX02’在2个时期对Ⅴ型菌株抗性表现极佳。‘BX02’与‘9311’杂交构建的F2遗传群体,抗性位点被定位在5号染色体,极大似然函数值达到40.6,该区间包含已克隆的水稻抗白叶枯病Ⅴ型菌xa5基因,序列扩增分析验证为白叶枯抗性基因xa5。【结论】筛选出在2个时期均抗白叶枯病Ⅴ型菌的水稻品种4个,抗Ⅸ型的水稻品种1个,为水稻抗白叶枯种质资源筛选提供了基础材料。

【Objective】The purpose is to screen rice varieties with resistance to the V and IX pathotypes of Xanthomonas oryzae pv.oryzae(Xoo).【Method】Ninety-seven brown planthopper resistant rice varieties collected from tropical and subtropical areas were surveyed against V and IX types of Xoo.The leaf-cutting inoculation method was used to identify the resistance level of rice varieties to bacterial blight at the seedling and adult stages.A mapping population was developed for a variety with excellent resistance performance,which was applied to map and clone the resistance genes.【Result】Twenty and eight rice varieties were detected to be resistant to V type at the seedling and adult stages respectively,and four varieties showed moderate or high resistance at both stages.Moreover,thirty-four and nine rice varieties were identified to be resistant to IX type at the seedling and adult stages respectively,and one variety showed moderate or high resistant level at both stages.Rice variety‘BX02’showed excellent resistance to V type of Xoo at both stages.Therefore,one F2 mapping population was developed by crossing‘BX02’with‘9311’,and the resistance locus was identified on chromosome 5 with the logarithm of adds(LOD)score of 40.6.This mapping interval contained the cloned xa5 gene with resistance to V type of Xoo.Sequence amplification analysis confirmed that it was the bacterial blight resistance gene xa5.【Conclusion】Four and one varieties were detected to be resistant to V and IX types of Xoo at both stages respectively,which provides materials for rice resistance breeding against the bacterial blight.