opaque-2玉米近等基因系的构建与赖氨酸含量快速检测

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

我国高赖氨酸玉米种质资源狭窄，opaque-2（02）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02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02突变基因导人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02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D2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D2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D2突变基因导入受体系，构建02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人D2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02近等基因系问，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D2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。

The germplasm of high lysine maize in China is narrow, while the opaque-2 （02） 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 02 gene into normal receptor lines cor- rectly, 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 18th group of o2-NILs by our own improved dye binding lysine （DBL） method. The results demonstrated that the normal maize inbred lines existed polymor- phism, moreover, polymorphism also existed among QPM donors CA339 and Shandong 2548, 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 con- tent in o2-NILs ranged from 13% to 74%. We included that the SSR marker phi057 can select the mutant genotype of 02 gene correctly, and the improved DBL method is effective to be used in high lysine maize breeding.