Aa PP 2C1 negatively regulates the expression of genes involved in artemisinin biosynthesis through dephosphorylating Aa APK 1

Artemisinin is biosynthesized in Artemisia annua and widely used for the treatment of malaria. Abscisic acid ( ABA )‐responsive kinase 1 (Aa APK 1), a member of the Sn RK 2 family, is involved in the regulation of artemisinin biosynthesis through the phosphorylation of Aab ZIP 1, which directly transactivates genes involved in artemisinin biosynthesis. Through diverse assays – including yeast two‐hybrid and bimolecular fluorescence complementation assays – we report that the ABA ‐responsive protein phosphatase Aa PP 2C1 physically interacts with Aa APK 1. In addition, phos‐tag mobility shift assays indicate that Aa PP 2C1 dephosphorylates Aa APK 1. Moreover, dual‐luciferase assays demonstrate that the presence of Aa PP 2C1 reduces the transactivation of artemisinin biosynthesis genes by Aab ZIP 1. These results further refine the post‐translational regulatory network of artemisinin biosynthesis, showing that Aa PP 2C1 is negatively involved through dephosphorylation of Aa APK 1.