不依赖基因型的高效玉米遗传转化体系的建立

Establishment of genotype-independent high-efficiency transformation system in maize

玉米遗传转化严重依赖于受体基因型,目前绝大部分商业化玉米骨干自交系的遗传转化仍然十分困难。Baby boom(Bbm)和Wuschel2(Wus2)是植物干细胞发育中的2个关键基因,调节这2个基因的时空表达可以有效提高植物遗传转化效率。本研究以多个我国玉米骨干自交系为受体材料开展转化效率测试,发现虽然Bbm和Wus2的超表达可以显著提高转化效率,但对玉米的生长发育具有不利影响。本研究开发了一种新型辅助转化技术,在辅助载体中加入致死基因表达元件,并调节2个基因的时空表达。结果表明该辅助载体和目标载体混合转化时,不但可以在T0代成功获得不含Bbm和Wus2辅助载体的正常生长发育的优质转化苗,还显著提高转化效率(平均达19.5%)。本研究成功建立和完善了一套不依赖基因型的高效玉米遗传转化体系,为提高生物育种效率和精准改良提供了有力支持。

The reliance on receptor genotype of genetic transformation made it difficult for the transformation of commercial maize lines.Expression regulation of two important genes in plant stem cell development,Baby boom(Bbm)and Wuschel2(Wus2),was revealed to significantly improve transformation efficiency.Several Chinese core maize inbred lines were used as receptor materials to test the transformation efficiency.Although the overexpression of Bbm and Wus2 could significantly improve the transformation efficiency,it had a negative impact on the growth and development of T0 plants.Here,a new assisted transformation technology was developed,in which a lethal gene element was added to the assist vector and the spatial expression of the two genes were regulated.The results revealed that the hybrid transformation of the assist vector and the target vector could not only successfully obtain high-quality transformation seedlings without Bbm and Wus2 assist vector in T0 generation,but also significantly improve the transformation efficiency with an average 19.5%.The application of this improved genotype-independent genetic transformation system promises maize precise improvement with higher efficiency.