Enhancement of artemisinin content by constitutive expression of the HMG-CoA reductase gene in high-yielding strain of Artemisia annua L.

Abstract

Artemisinin is effective against both chloroquine-resistant and -sensitive strains of Plasmodium species. However, the low yield of artemisinin from cultivated and wild plants is a serious limitation to the commercialization of this drug. Optimization of artemisinin yield either in vivo or in vitro is therefore highly desirable. To this end, we have overexpressed the 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGR) gene (hmgr) from Catharanthus roseus L. in Artemisia annua L. and analyzed its influence on artemisinin content. PCR and Southern blot analyses revealed that the transgenic plants showed stable integration of the foreign hmgr gene. The reverse transcriptase-PCR results suggested that the hmgr was expressed at the transcriptional level in transgenic lines of Artemisia annua L., while the high-performance liquid chromatography analysis showed that artemisinin content was significantly increased in a number of the transgenic lines. Artemisinin content in one of the A. annua transgenic lines was 38.9% higher than that in non-transgenic plants, and HMGR enzyme activity in transgenic A. annua L. was also higher than that in the nontransgenic lines.

Molecular cloning, characterization, and promoter analysis of the isochorismate synthase (AaICS1) gene from Artemisia annua

“…In the SA biosynthetic pathway of the transgenic A. annua, overexpression of the key enzyme genes could be an effective way to increase the artemisinin content (Han et al, 2006;Aquil et al, 2009;Banyai et al, 2010;Nafis et al, 2011). As SA treatment can improve the artemisinin content, the overexpression of a key gene in the SA biosynthesis pathway might increase endogenous SA, leading to improved artemisinin content (Fig.…”

Overexpression of the cytochrome P450 monooxygenase (cyp71av1) and cytochrome P450 reductase (cpr) genes increased artemisinin content in Artemisia annua (Asteraceae)

“…Overexpression of the key enzyme genes of the artemisinin biosynthetic pathway has shown to be effective in increasing the artemisinin content in transgenic A. annua (Han et al, 2006;Aquil et al, 2009;Banyai et al, 2010;Nafis et al, 2011). We used leaves 10, 15 and 20 (counting from the apical meristem) from 20-week-old greenhouse-grown A. annua for HPLC analysis.…”

Bioactive Plant Isoprenoids

“…HMG-CoA reductase (HMGR) is a key enzyme of the MVA pathway, which regulates the carbon flux through the artemisinin route, thereby limiting its production. A very recent experiment by Nafis et al, 2011, involved the overexpression of this rate-limiting enzyme in A. annua, resulting in a significant increase in the overall artemisinin content of the transgenic A. annua plants [94]. The enzyme, FPPS, has also been successfully overexpressed in transgenic A. annua plants.…”