Singlet oxygen as a signaling transducer for modulating artemisinin biosynthetic genes in Artemisia annua

Although crosstalk between cytosolic and plastidic terpenoid pathways has been validated in many plant species, we report here for the first time a striking elevation of the nucleus-encoded artemisinin biosynthesis relevant DBR2 mRNA following the incubation of plants with fosmidomycin (FM). FM decreased singlet oxygen ( 1 O 2 ) scavengers such as β-carotene and α-tocopherol and subsequently invoked 1 O 2 burst. The treatment of plants with fluridone (FD) neither decreased α-tocopherol content nor triggered 1 O 2 emission. In conclusion, FM can up-regulate 1 O 2 -sensitive nuclear genes responsible for artemisinin biogenesis by mitigating the accumulation of plastidic scavenging terpenoids, thereby eliciting 1 O 2 generation and initiating 1 O 2 retrograde signaling.