水稻白叶枯病抗性基因Xa4、Xa23聚合及分子标记检测

Pyramiding and Identifying of Bacterial Blight Resistant Genes Xa4 and Xa23 in Rice

本研究以含Xa23的水稻品种WBB1为亲本,分别与含Xa4的恢复系杂交,对后代进行白叶枯病菌系接种及SSR分子标记检测,进行Xa23和Xa4的聚合及Xa23显性程度观察,研究结果如下:1.含Xa23亲本与不同遗传背景品种杂交,F1代经鉴别菌系C1～C7及毒力强的P6接种,表现抗谱广。2.利用SSR标记RM206进行Xa23和Xa4杂交聚合的检测,RM206与Xa23紧密连锁且共分离,在亲本间存在多态性,在后代选择中准确性好。桂99×WBB1、R402×WBB1和IR30×WBB1的F2群体中的准确率分别达到了97%、96%和98%。这说明利用SSR标记RM206对白叶枯病抗性基因Xa23进行分子辅助选择育种是切实可行的。3.Xa23与Xa4聚合体比含Xa4的恢复系对白叶枯病的抗性有很大的提高,经C1～C7菌系接种,病斑普遍在1cm以下,抗性水平达到高抗水平。

In this study, we made several crosses between rice variety WBB1 containing bacterial blight resistant gene Xa23 and the restoring lines containing the bacterial blight resistant gene Xa4.Tbe FlS and individuals of F2 generation were used to be inoculated by bacterial blight strains and to be identified by SSR markers in order to integrate the Xa23 and Xa4 gene and understand their dominant characters. First, the results showed that the FlS derived from WBB1 mating with other different background cultivars present broad resistant to bacterial blight strains C1-C7 and the high poisonous strain P6. Secondly, the SSR marker RM206 closely linked to Xa23 was employed to identify the combinations of Xa23 and Xa4 in this study, the results showed that the marker could be used for polymorphic analysis in the parents and gene selection in the progenies. In the F2 progenies derived from the crosses of Gui99×WBB1, R402×WBB1 and IR30×WBB1, the MAS efficiencies of RM206 were up to 97%, 96% and 98%, respectively. The results further indicated that the RM206 marker should be a very useful marker for the Xa23 gene validation in the molecular assisted selection breeding program.Thirdly, the lension length of the lines with Xa23 and Xa4 were below 1.0 cm, which obviously smaller than that of the lines with single Xa4 gene by inoculation with bacterial blight strains C1-C7, the results indicated that the combination of Xa23 and Xa4 could acquire higher resistant level than that of Xa .