An ecological implication of glandular trichome-sequestered artemisinin: as a sink of biotic/abiotic stress-triggered singlet oxygen

Artemisinin is accumulated in wormwood (Artemisia annua) with uncertain ecological implications. Here, we suggest that artemisinin is generated in response to biotic/abiotic stress, during which dihydroartemisinic acid, a direct artemisinin precursor, quenches singlet oxygen (¹O₂), one kind of reactive oxygen species. Evidence supporting artemisinin as a sink of ¹O₂ emerges from that volatile isoprenoids protect plants from biotic/abiotic stress; biotic/abiotic stress induces artemisinin biosynthesis; and stress signaling pathways are involved in the biosynthesis of volatile isoprenoids among plants as well as the biosynthesis of artemisinin in A. annua. In this review, we address the ecological implication of glandular trichome-sequestered artemisinin as a sink sink of biotic/abiotic stress-triggered ¹O₂ , and also summarize the cumulating data on the transcriptomic and metabolic profiling of stress-enhanced artemisinin production upon eliciting ¹O₂ omission from chloroplasts and initiating retrograde ¹O₂ signaling from chloroplasts to nuclei.