Molecular insights into AabZIP1-mediated regulation on artemisinin biosynthesis and drought tolerance in .

is the main natural source of artemisinin production. In , extended drought stress severely reduces its biomass and artemisinin production while short-term water-withholding or abscisic acid (ABA) treatment can increase artemisinin biosynthesis. ABA-responsive transcription factor AabZIP1 and JA signaling AaMYC2 have been shown in separate studies to promote artemisinin production by targeting several artemisinin biosynthesis genes. Here, we found AabZIP1 promote the expression of multiple artemisinin biosynthesis genes including and , which AabZIP1 does not directly activate. Subsequently, it was found that AabZIP1 up-regulates expression through direct binding to its promoter, and that AaMYC2 binds to the promoter of to activate its transcription. In addition, AabZIP1 directly transactivates wax biosynthesis genes and . The biosynthesis of artemisinin and cuticular wax and the tolerance of drought stress were significantly increased by overexpression, whereas they were significantly decreased in RNAi- plants. Collectively, we have uncovered the AabZIP1-AaMYC2 transcriptional module as a point of cross-talk between ABA and JA signaling in artemisinin biosynthesis, which may have general implications. We have also identified AabZIP1 as a promising candidate gene for the development of plants with high artemisinin content and drought tolerance in metabolic engineering breeding.