Cloning and functional analysis of JAZ genes in Artemisia annua

Jasmonic acid (JA) can promote the biosynthesis of artemisinin.To have an insight into the JA signaling in Artemisia annua,two new genes belonging to JAZ family,namely AaJAZ5 and AaJAZ6,were cloned from Artemisia annua,which might be the negative regulators involved in the JA signaling pathway.Bioinformatic analysis showed that AaJAZ5 and AaJAZ6 contained the conserved domains of ZIM and Jas specific to JAZ family.According to tissue profile analysis,AaJAZ5 had the highest expression level in leaf and AaJAZ6 had the highest expression level in root.The expression levels of both AaJAZ5 and AaJAZ6 were markedly elevated by methyl jasmonate and mechanical wounding.The BiFC results indicated that AaJAZ5,as well as AaJAZ6,physically interacted with AaMYC2.Importantly,only AaJAZ5 could interact with AaCOI1.The interaction assays given by BiFC suggested that AaJAZ5 might play a crucial role in JA signaling.This study facilitated the further analysis of the functional divergence of JAZ-family members and the understanding of molecular mechanism on JA signaling to regulate the artemisinin biosynthesis.