AaMYB108 is the core factor integrating light and jasmonic acid signaling to regulate artemisinin biosynthesis in Artemisia annua.

Artemisinin, a sesquiterpene compound synthesized and stored in the glandular trichome of Artemisia annua leaves, has been used to treat malaria. Previous studies have shown that both light and jasmonic acid can promote the biosynthesis of artemisinin, and the promotion of artemisinin by jasmonic acid is dependent on light. However, the specific molecular mechanism remains unclear. Here, we report a MYB transcription factor, AaMYB108, identified from transcriptome analysis of light and jasmonic acid treatment, as a positive regulator of artemisinin biosynthesis in A. annua. AaMYB108 promotes artemisinin biosynthesis by interacting with a previously characterized positive regulator of artemisinin, AaGSW1. Then, we found that AaMYB108 interacted with AaCOP1 and AaJAZ8, respectively. The function of AaMYB108 was influenced by AaCOP1 and AaJAZ8. Through the treatment of AaMYB108 transgenic plants with light and jasmonic acid, it was found that the promotion of artemisinin by light and jasmonic acid depends on the presence of AaMYB108. Taken together, our results reveal the molecular mechanism of jasmonic acid regulating artemisinin biosynthesis depending on light in A. annua. This study provides new insights into integration of light and phytohormone signaling to regulate terpene biosynthesis in plants.