opaque-2玉米近等基因系的构建与赖氨酸含量快速检测

我国高赖氨酸玉米种质资源狭窄，opaque-2(o2)突变基因能大幅提高玉米赖氨酸含量，通过分子标记辅助选择构建o2玉米近等基因系并检测其赖氨酸含量具有重要意义。其中，要解决的两个关键问题是如何准确地将不同供体的o2突变基因导入受体系和如何快速地检测导入系的赖氨酸含量。本研究利用O2基因内紧密连锁的SSR共显性标记引物phi057检测玉米供体和受体自交系的多态性，利用其特异性和共显性构建o2近等基因系；参考已有研究，改进染料结合(DBL)法，测定18组构建成功的o2近等基因系的赖氨酸含量。结果表明，不仅在不同供体(CA339和山东2548)之间存在多态性，而且在不同受体系间也存在多态性，利用phi057能够成功地将不同供体的o2突变基因导入受体系，构建o2近等基因系；改进的DBL法分析表明，不同受体系赖氨酸含量变化较大，不同背景的受体系导入o2突变基因后赖氨酸含量增加的幅度差异也较大；普通玉米自交系间赖氨酸含量为0.223%~0.368%，构建成功的不同o2近等基因系间，赖氨酸含量为0.373%~0.527%，与受体亲本相比，赖氨酸增加幅度最低为13%，最高为74%。分析表明，phi057能准确筛选导入o2突变基因的受体系，结合改进的DBL法能快速地选择赖氨酸含量高的玉米。

Construction of Maize opaque-2 Near-isogenic Lines and Rapid Detection of Lysine Content

The germplasm of high lysine maize in China is narrow, while the opaque-2 (o2) mutant gene can largely increase the lysine level in maize, so it is important to create opaque-2 near-isogenic lines (o2-NILs) by molecular marker assisted selection (MAS). There are two key problems in creating such lines, one is how to introgress the o2 gene into normal receptor lines correctly, and the other is the fast and convenient way to monitor the lysine content. In our study, the closely linked co-dominant SSR marker phi057 was used to detect the polymorphism between the maize donor and receptor lines, and the specific and co-dominant marker was used to construct o2-NILs. Meanwhile, we tested the lysine content of 18s group of o2-NILs by our own improved dye binding lysine (DBL) method. The results demonstrated that the normal maize inbred lines existed polymorphism, moreover, polymorphism also existed among QPM donors CA339 and Shandong2548, the marker phi057 was effective to construct o2-NILs, using different QPM donors. The lysine content varied in different genetic backgrounds, which was from 0.223% to 0.368% among normal maize inbred lines, and from 0.373% to 0.527% among o2-NILs. The increment of lysine content in o2-NILs ranged from 13% to 74%. We included that the SSR marker phi057 can select the mutant genotype of o2 gene correctly, and the improved DBL method is effective to be used in high lysine maize breeding.