According to the World Health Organization (WHO), malaria has affected about 216 million people in 91 countries in 2016, and caused around 445,000 deaths all over the globe in the same year only. A. annua is the main source of artemisinin, the only WHO recommended treatment for the devastating disease. Thus, the researchers identified the genes involved in making artemisinin and modified the plant to make it produce three times more drug than the usual amount. They did this by simultaneously increasing the activity of three genes, HMGR, FPS, and DBR2.
Figure 4: Genome and RNA-Seq Guided Plant Metabolic Engineering to Increase Artemisinin Content in A. annua.
(A) Relative expression levels of HMGR, FPS, and DBR2 in wild-type and four independent transgenic A. annua overexpression lines determined by qPCR.
(B) HPLC analysis of artemisinin content in wild-type and four independent HMGR, FPS, and DBR2-overexpressing transgenic A. annua lines.
(C) Three-month-old transgenic A. annua lines overexpressing HMGR, FPS, and DBR2 (middle and right) and wild-type (left) after 3 g/l glyphosate ammonium treatment. Data represent the means ± SE from three replicates. The â-actin gene (GenBank: EU531837.1) was used as the control for gene expression normalization.
Statistical significance was determined by two-independent-samples Æ test (**P < 0.01). Asterisks indicate the differences between wild-type and transgenic lines.