Shen Qian, Huang Huayi, Zhao Yu, Xie Lihui, He Qian, Zhong Yijun, Wang Yuting, Wang Yuliang, Tang Kexuan
Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
Front Plant Sci. 2019 Nov 7;10:1294. doi: 10.3389/fpls.2019.01294. eCollection 2019.
Artemisinin-based therapies are the only effective treatment for malaria, which reached to 219 million cases and killed 435,000 people in 2017. To meet the growing demand for artemisinin and make it accessible to the poorest, genetic engineering of becomes one of the most promising approaches to improve artemisinin yield. In this work, AabZIP9 transcription factor has been identified and characterized. The expression profile of revealed that it was clustered with the artemisinin specific biosynthetic pathway genes , , , and . Furthermore, the transiently dual-LUC analysis showed that the activation of promoter was enhanced by AabZIP9. Meanwhile, yeast one-hybrid assay showed that AabZIP9 was able to bind to the "ACGT" -element present in both and promoters. AabZIP9 gene was driven by the constitutive CaMV35S promoter and the glandular trichome specific CYP71AV1 promoter and stably transformed into plants. The transcript level of AabZIP9 was increased in both of the 35S and CYP71AV1 driven transgenic plants compared with the wild type or GUS control plants. All the transgenic plants overexpressing showed elevated transcript level of , but the transcription levels of , , and have no significant change in both types of transgenic plants. The significantly upregulated promoted the accumulation of artemisinin, dihydroartemisinic acid, and artemisinic acid biosynthesis in the transgenic plants. These results suggest that AabZIP9 can positively regulate the biosynthesis of artemisinin.
以青蒿素为基础的疗法是治疗疟疾的唯一有效方法，2017年疟疾发病病例达2.19亿例，造成43.5万人死亡。为了满足对青蒿素日益增长的需求并使其能为最贫困人群所用，基因工程成为提高青蒿素产量最具前景的方法之一。在这项研究中，已鉴定并表征了AabZIP9转录因子。其表达谱显示它与青蒿素特异性生物合成途径基因、、、和聚集在一起。此外，瞬时双荧光素酶分析表明AabZIP9增强了启动子的活性。同时，酵母单杂交试验表明AabZIP9能够与和启动子中存在的“ACGT”元件结合。AabZIP9基因由组成型CaMV35S启动子和腺毛特异性CYP71AV1启动子驱动，并稳定转化到植物中。与野生型或GUS对照植物相比，在35S和CYP71AV1驱动的转基因植物中AabZIP9的转录水平均有所增加。所有过表达的转基因植物中，的转录水平均升高，但在这两种转基因植物中，、和的转录水平均无显著变化。显著上调的促进了转基因植物中青蒿素、二氢青蒿酸和青蒿酸生物合成的积累。这些结果表明AabZIP9可以正向调节青蒿素的生物合成。
