青蒿鲨烯合酶基因打靶研究

Gene targeting of squalene synthase in Artemisia annua

目的通过代谢途径工程调整代谢流向,试图增大转基因青蒿Artemisia annua植株中的青蒿素产量。方法利用青蒿鲨烯合酶(SS)基因、绿色荧光蛋白(GFP)基因和胞嘧啶脱氨酶(CodA)基因构建基因打靶载体,并通过冻融法将载体导入根癌农杆菌Agrobacterium tumefaciens。以叶盘法转化青蒿,采用"分段选择法"筛选转基因再生植株。结果对表达GFP基因后发出绿色荧光的转基因植株,采用PCR及PCR产物杂交法,在1棵转基因植株中检测到外源GFP基因,而未检测到内源SS基因。初步证据显示,在转基因青蒿植株中,突变型SS基因已取代野生型SS基因。结论青蒿鲨烯合酶基因打靶已取得初步成功。

Objective To increase artemisinin yield in transgenic Artemisia annua plants by regulating metabolic affluxion through metabolic pathway engineering. Methods The gene targeting vector was constructed by squalene synthase （SS） gene of A. annua, green fluorescent protein （GFP） gene, and cytosine deaminase （CodA） gene, and the vector was introduced into Agrobacterium tumefaciens by freeze- thawing procedure. A. annua was transformed through Leaf Disk method and regenerated transgenic plants were screened by the ＂Step-by-Step Selection＂. Results Among the transgenic A. annua plants emitting green fluorescence after expression of GFP gene, the exogenous GFP gene rather than endogenous SS gene was detected in one transgenic plant by PCR as well as hybridization of PCR products. The preliminary data showed that the wild-type SS gene was replaced by mutated SS gene in the transgenic A. annua plant. Conclusion Gene targeting of squalene synthases of A. annua is successful.