"Artemisinin is a potent antimalarial drug produced in the plant Artemisia annua. Earlier reports suggested that the roots play a key role in artemisinin production; however, it was not clear if other factors actually affected production instead of roots. Here the role of roots and two phytohormones, NAA and BAP, were studied to determine what role each plays in artemisinin production in the plant. Rooted Artemisia annua shoots produced significantly more artemisinin, arteannuin B, and deoxyartemisinin, the end products in the pathway, than unrooted shoots. Although roots do not seem to affect the levels of precursors, artemisinic acid and dihydroartemisinic acid, or regulate the transcription of the genes in the pathway, rooted plants developed larger trichome sacs suggesting that the accumulation of end products is linked to the expansion of the trichome sac. Unrooted shoots are grown in shooting medium containing higher amount of MS salts, vitamins, sucrose and two potent phytohormones, NAA and BAP. Rooted shoots grown in rooting medium containing either one or both of these hormones showed that NAA increased production of arteannuin B in the young leaves and artemisinin in the mature leaves; in mature leaves, however, arteannuin B was inhibited by NAA. BAP induced production of both the precursors and the end products, except for artemisinin, in the young and/or mature leaves. When rooted shoots with their roots removed were grown in rooting medium containing either one of these hormones, artemisinin was significantly less in cultures grown with BAP while there were no differences in metabolite levels in cultures grown with NAA. Although the importance of roots on the artemisinin biosynthetic pathway cannot be concluded, these results help improve our understanding of artemisinin biosynthesis as may prove useful for improving artemisinin production in field-grown crops."
| Identifer | oai:union.ndltd.org:wpi.edu/oai:digitalcommons.wpi.edu:etd-theses-2104 |
| Date | 06 December 2011 |
| Creators | Nguyen, Khanh Van T |
| Contributors | Pamela J. Weathers, Advisor, Kristin K. Wobbe, Committee Member, Luis Vidali, Committee Member |
| Publisher | Digital WPI |
| Source Sets | Worcester Polytechnic Institute |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Masters Theses (All Theses, All Years) |
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