Tetraploid Artemisia annua hairy roots produce more artemisinin than diploids

Abstract

Hairy root cultures of diploid Artemisia annua L. (clone YUT16) grow rapidly and produce the antimalarial sesquiterpene artemisinin. Little is known about how polyploidy affects the growth of transformed hairy roots and the production of secondary metabolites. Using colchicine, we produced four stable tetraploid clones of A. annua L. from the YUT16 hairy root clone. Analysis showed major differences in growth and artemisinin production compared to the diploid clone. Tetraploid clones produced up to six times more artemisinin than the diploid parent. This study provides an initial step in increasing our understanding of the role of polyploidy in secondary metabolite production, especially in hairy roots.

Enhancement of artemisinin content in tetraploidArtemisia annuaplants by modulating the expression of genes in artemisinin biosynthetic pathway

“…It was reported that averaged artemisinin level in tetraploids was 38% higher as compared with the diploid progenitor during the whole vegetation period. Similar result was also reported in the tetraploid hairy root 18, further supporting that synthetic autotetraploids could increase the artemisinin content. But owing to the lower biomass accumulation, the net yield of artemisinin per square meter of field‐grown plants decreased by 25% 17.…”

“…Polyploidization has been shown to be effective in increasing the average artemisinin content in leaf and hairy roots 17,18. In our experiment, HPLC showed a significant enhancement of artemisinin content in a range from 39% to 56% in tetraploid plants compared with their diploid parents (Fig.…”

Sesquiterpenoids Lactones: Benefits to Plants and People

“…Artemisinin (Figure 1O) is a sesquiterpene lactone of the cadinanolide, one of the characteristic metabolites in Artemisia annua , where it is produced in shoots and roots (which are considered the most important organ in artemisinin production) and transported to trichomes of the leaves [80–82]. Delabays et al [83] found it was stored in the highest levels in the upper leaves.…”

“…It has also been noted that the presence of reactive O 2 could be responsible for the conversion of artemisinic acid (Figure 1P) to artemisinin [85], and hence this could cause the effect seen. De Jesus-Gonzalez and Weathers [82] report that ploidy can have a great effect on artemisinin levels with up to 6× more artemisinin being reported in their YUT16-7P tetraploid culture as in the YUT16 diploid. Equally, addition of arbuscular micorhizzae, particularly Glomus fasciculatum , has been shown to increase levels of artemisinin in A. annua [86].…”

Contrasting effects of ploidy level on seed production in a diploid tetraploid system

“…Previous studies, usually comparing diploids and synthetic polyploids (e.g. De Jesus-Gonzalez and Weathers 2003; Caruso et al 2011; Lavania et al 2012; Cohen et al 2013), demonstrated that higher ploidy levels are characterized by a higher content of secondary metabolites and thus better anti-herbivore defence, while opposite pattern was found only rarely (Repcak and Krausová 2009). In C. phrygia , six different metabolites occurring in higher concentrations in diploid flower heads have been detected, while only two metabolites were more abundant in the flower heads of tetraploids (Münzbergová et al 2015).…”