Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA.
Department of Chemistry, North Carolina State University, Raleigh, NC, USA.
Mol Plant. 2019 May 6;12(5):704-714. doi: 10.1016/j.molp.2019.02.011. Epub 2019 Mar 6.
Artemisinin-based combination therapy (ACT) forms the first line of malaria treatment. However, the yield fluctuation of artemisinin has remained an unsolved problem in meeting the global demand for ACT. This problem is mainly caused by the glandular trichome (GT)-specific biosynthesis of artemisinin in all currently used Artemisia annua cultivars. Here, we report that non-GT cells of self-pollinated inbred A. annua plants can express the artemisinin biosynthetic pathway. Gene expression analysis demonstrated the transcription of six known pathway genes in GT-free leaves and calli of inbred A. annua plants. LC-qTOF-MS/MS analysis showed that these two types of GT-free materials produce artemisinin, artemisinic acid, and arteannuin B. Detailed IR-MALDESI image profiling revealed that these three metabolites and dihydroartemisinin are localized in non-GT cells of leaves of inbred A. annua plants. Moreover, we employed all the above approaches to examine artemisinin biosynthesis in the reported A. annua glandless (gl) mutant. The resulting data demonstrated that leaves of regenerated gl plantlets biosynthesize artemisinin. Collectively, these findings not only add new knowledge leading to a revision of the current dogma of artemisinin biosynthesis in A. annua but also may expedite innovation of novel metabolic engineering approaches for high and stable production of artemisinin in the future.
青蒿素类复方疗法（ACT）是治疗疟疾的一线药物。然而，青蒿素的产量波动一直是满足全球对 ACT 需求的一个未解决的问题。这个问题主要是由所有目前使用的黄花蒿品种的腺毛（GT）特异性生物合成青蒿素引起的。在这里，我们报告自交系黄花蒿植物的非 GT 细胞可以表达青蒿素生物合成途径。基因表达分析表明，GT 缺失的自交系黄花蒿叶片和愈伤组织中六个已知途径基因的转录。LC-qTOF-MS/MS 分析表明，这两种 GT 缺失材料都能产生青蒿素、青蒿酸和青蒿素 B。详细的 IR-MALDESI 图像分析显示，这三种代谢物和二氢青蒿素定位于自交系黄花蒿叶片的非 GT 细胞中。此外，我们还采用了上述所有方法来研究已报道的黄花蒿无腺毛（gl）突变体中的青蒿素生物合成。所得数据表明，再生 gl 植株叶片能够合成青蒿素。总的来说，这些发现不仅增加了关于黄花蒿青蒿素生物合成的新知识，导致对当前教条的修正，而且可能加速未来高产量和稳定生产青蒿素的新型代谢工程方法的创新。
