Germplasm Release of Four High-artemisinin Clones of Artemisia annua L.

Abstract

Malaria morbidity is currently on rise and artemisinin combination therapy (ACT) is still the only reliable line of treatment to cure quinine-resistant malaria and the only natural medicine to have a drastic impact on malaria control worldwide. However, commercial cultivars of Artemisia annua (the only commercial source of artemisinin) are only available from a couple of producers in the world and the price is steep for farmers in developing countries afflicted by malaria. Artemisia annua is the only commercial source of artemisinin and produces other compounds that are reported to enhance the antimalarial effect of artemisinin. Although China produces the most artemisinin for the manufacture of ACT, Africa has expanded the cultivation of annual wormwood since 2004. However, high-artemisinin cultivars are not easily available, and it is paramount that countries afflicted by malaria have access to high-artemisinin genotypes of A. annua. During several years, we have selected high-artemisinin genotypes of A. annua, among Brazilian and Chinese genotypes, that can produce from 1.6-2.0% artemisinin on a dry weight basis and high shoot biomass. One of the genotypes (C1) produced 2.16% artemisinin and 3.22 tons of dry leaves·ha-1, based on one plant·m2. Both shoot dry mass/ha and artemisinin can be significantly increased as more plants are used per m2, to a point. Our yield based on 1.0 plant.m2 was twice the average concentration of artemisinin currently reported for commercial cultivars and with estimated potential to produce 70.7 kg artemisinin·ha-1. Our selections were tested under field, greenhouse and tissue culture conditions, and field-selected for high artemisinin. These plants can more than double commercial artemisinin production when used as vegetatively-propagated clones and can reduce both the current market price of artemisinin and of artemisinin-derived ACT. We hereby release our high-artemisinin clones to be used as parents in breeding programs that will result in new lines with higher artemisinin concentration than the ones currently available. The high-artemisinin clones can be an asset in both breeding and research programs destined to produce elite Artemisia germplasm to be distributed among farmers engaged in producing artemisinin as the raw material for antimalaria drugs such as ACT.