Production of Tropane Alkaloids (TAs) in Plants and In Vitro Cultures of Different Ploidy Levels

Owning multiple pharmaceutical functions, plant-derived tropane alkaloids, especially scopolamine, have been widely used in medicine. Significant progress has been made in the production of tropane alkaloids during the past decades via breeding and cultivation of Duboisia cultivates, which are rich in scopolamine. However, unpredicted effects of environmental conditions and the progressive impact of global climate change are two major challenges for sustainable production of these compounds in the near future. In vitro cultures offer a powerful alternative source of TA production which address the uncontrolled effects of environmental variables under field cultivation and most importantly ease manipulation of the culture systems to maximize productivity. However, low quality or quantity of certain TA is still one of the biggest challenges that limit applicability of in vitro cultures. As an evolutionary phenomenon, polyploidy has been known to impact almost all characteristics of a plant species including pharmaceutically important traits such as biomass production and secondary metabolism. However, application of polyploidy has been underestimated and unexplored in production of tropane alkaloids. Here, we review recent progresses in the application of polyploidy in improving the quantity and quality of TA production in plants and in vitro cultures of TA-producing plant species. We also discuss the future directions of the polyploidy research in this field.