江苏部分粳稻品种和品系中稻瘟病抗性基因Pi-ta和Pi-b的基因型分析（英文）

Genotypic Analysis of Rice Blast Resistance Genes Pi-ta and Pi-b in Japonica Rice Varieties and Lines in Jiangsu Province

基因Pi-ta和Pi-b是最早被克隆的两个稻瘟病抗性基因,在粳稻中表现出持久稳定的稻瘟病抗性,因而被广泛用于稻瘟病抗性育种。为明确上述基因在江苏粳稻中的分布,为抗病育种提供依据,该研究利用Pi-ta和Pi-b的功能标记,对40个粳稻品种和665份粳稻新品系进行相关基因型的分子检测。结果表明,抗性基因Pi-ta和Pi-b在江苏粳稻品种中具有一定的分布,其中Pi-b的分布频率高于Pi-ta的频率,连粳系列品种大都不携带Pi-ta和Pi-b抗性基因,而武粳系列品种则基本含有上述抗性基因。粳稻新品系携带抗性基因Pi-ta的频率与推广品种相比变化不大,但携带抗性基因Pi-b的频率明显高于推广品种,这说明人工改良水稻品种有利于抗病基因Pib频率的提高。4种基因型中,Pi-ta/Pi-b的分布频率最高,为60.0%,其次为Pi-ta/Pi-b,占33.5%,基因型Pi-ta/Pi-b的分布频率为3.9%,而Pi-ta/Pi-b的分布频率最低,只占2.6%。从4个组合的抗性基因来源看,抗性基因Pi-ta则可能来自武香粳14、武粳15或南粳44,而Pib则可能来自武粳13、武香粳14、武粳15或南粳44。从4种基因型后代的获得频率看,以南粳44//武粳13/关东194获得抗性基因型Pi-ta/Pi-b后代的频率最高。

Pi-ta and Pi-b, the first cloned rice blast resistant genes, have been wide- ly used in rice blast resistance breeding for their lasting and stable resistance. To define the distribution of Pi-ta and Pi-b in japonica rice in Jiangsu, the genotypes of resistance genes Pi-ta and Pi-b in 40 varieties and 665 new lines were detected using functional markers of Pi-ta/pi-ta and Pi-b^pi-b alleles. The results showed that the resistance alleles of Pi-ta and Pi-b were widely spread in japonica rice varieties, and the distribution frequency of Pi-b was higher than that of Pi-ta. Most of the Lianjing serial varieties didn＇t carry the two resistance genes, but the two resistance genes were widely distributed in Wujing serial varieties. There was no significant dif- ference in distribution frequency of Pi-ta between new lines and commercial vari- eties. However, the distribution frequency of Pi-b in new lines was higher than that in commercial varieties. It was indicated that artificial selection was conducive to the improvement of distribution frequency of Pi-b in rice varieties. Among the 4 genotypes, the distribution frequency of pi-taJPi-b was highest （60.0%）, followed by Pi-ta/ Pi-b （33.5%） and pi-ta/pi-b （3.9%）. The frequency of Pi-taJpi-b was lowest, account- ing for only 2.6%. In terms of source of resistance genes in the four combinations, the resistant allele Pi-ta might be from parents of Wuxiangjing14, Wujing15 or Nanjing44, and Pi-b might come from parents of Wujing13, Wuxiangjing14, Wujing15 or Nanjing44. The analysis on the genotypic frequencies in offspring of the rice vari- eties showed that the resistance genotype of Pi-ta/Pi-b had the highest frequency in the cross combination of Nanjing44//Wujing13/Kantou194.