滇型杂交水稻恢复系Rf1基因功能丢失现象及其突变体特性鉴定

Identification of Loss of Rf1 Gene Function Phenomenon in Restorer Line and Its Mutant of Dian-Type Hybrid Rice

本研究通过对优质丰产滇型杂交粳稻‘滇禾优34’杂种F1群体中不育株进行分类调查,结合骨干恢复系‘南34’及其Rf1恢复基因功能丢失突变体基本农艺性状和生物信息学分析,初步探明恢复系恢复基因功能丢失的现象和成因。结果表明,‘南34’的自然突变致使恢复基因Rf1功能丧失是导致‘滇禾优34’杂种F1群体出现不育株(两年占比分别为0.26%和0.79%)的主要因素;‘南34’野生型的结实率相对于其突变体无明显差异,在花粉育性、株高、穗长、粒长性状上野生型略高于突变体,在粒宽性状上突变体略大于野生型。通过克隆恢复系‘南34’野生型及突变体的Rf1位点,测序比对后发现在其ORF区域突变体相对于野生型缺失一段长为574 bp的序列,使其无法编码一些PPR蛋白,该序列的缺失可能导致恢复功能丧失。该研究结果为水稻三系育种和应用中恢复基因遗传变异机制的解析奠定理论基础。

In this study,we carried out a classification survey on sterile plants in the F1 population of high-quality and high-yield Dian-type japonica hybrid rice'Dianheyou 34',combining with the basic agronomic traits and biological information of the backbone restorer line'Nan34'and its mutant Rf1 restorer gene lost mutant,the phenomenon and cause of function loss of restorer lines were preliminarily explored.The results showed that the loss of function with natural mutation at Rf1 in'Nan34'was the main factor that led to sterile plants(two years accounted for 0.26%and 0.79%respectively)in'Dianheyou 34'F1 hybrid population;the seed setting rate of'Nan34'wild type was no significant difference compared with its mutant,and the wild type was slightly higher than the mutant in pollen fertility,plant height,ear length and grain length,and slightly greater than the wild type in grain width.By cloning the Rf1 locus of'Nan34'wild type and its mutant,we found that the mutant in ORF region lost a 574 bp long sequence compared with the wild type,which made it unable to encode some PPR proteins.The loss of this sequence may lead to the loss of recovery function.The results lay a theoretical foundation for revealing genetic variation mechanism of restorer genes in three-line hybrid rice breeding and utilization.