The Transcription Factor Aabzip9 Positively Regulates the Biosynthesis of Artemisinin in .

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.