Engineered plants produce malaria drug efficiently

Artemisinin, the primary component of standard combination therapies for malaria, is still relatively expensive and in short supply in some developing countries where the disease is endemic. Researchers are now trying to make the drug more accessible by engineering tobacco plants in two different ways to produce it with better efficiency. Extracting and purifying artemisinin from its natural plant source is expensive, and the plant, sweet wormwood, does not grow well in climates where malaria is common. An artemisinin precursor can be made in engineered yeast, but conversion to the final product has proved difficult to scale up. Artemisinin has also been made in singly engineered tobacco plants, but only in low yield. Shashi Kumar of the International Centre for Genetic Engineering & Biotechnology and coworkers have boosted the efficiency of the process by engineering two metabolic pathways in tobacco (Mol. Plant 2016, DOI: 10.1016/j.molp.2016.09.013). Artemisinin isolated from the doubly transgenic plant inhibits malaria parasite growth in red blood cells, and intact cells from the plant reduce levels of the parasite in the blood of infected mice more effectively than commercial artemisinin. The researchers now plan to replicate the work in lettuce, a potentially more suitable medium than tobacco for oral administration.