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

摘要

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 al eles. The results showed that the resistance al eles 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. lt was indicated that artificial selection was conducive to the improvement of distribution frequency of Pi-b in rice varieties. Among the 4 geno-types, the distribution frequency of pi-ta/Pi-b was highest (60.0%), fol owed by Pi-ta/Pi-b (33.5%) and pi-ta/pi-b (3.9%). The frequency of Pi-ta/pi-b was lowest, account-ing for only 2.6%. ln terms of source of resistance genes in the four combinations, the resistant al ele Pi-ta might be from parents of Wuxiangjing14, Wujing15 or Nan-jing44, 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.%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，本研究利用 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 Pi-b频率的提高。四种基因型中， 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 Pi-b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。