Tuesday 16 October 2012, 12.15PM
Speaker: Dr. Thilo Winzer (University of York)
Opium poppy (Papaver somniferum) remains one of the most important medicinal plants in the world, due to it containing a diverse set of benzylisoquinoline alkaloids (BIAs) with potent pharmaceutical activities. The principal components are the powerful analgesics morphine and codeine. In addition to these, opium poppy produces the alkaloid noscapine, which is widely used as a cough suppressant and has also been shown to act as a potent antitumor agent. While the biosynthesis of morphine and codeine has been well characterised at the molecular and biochemical level, virtually nothing was known about noscapine biosynthesis. By comparing varieties of opium poppy that make noscapine with those that do not we discovered that the pathway for biosynthesis of noscapine is controlled by a complex cluster of ten genes encoding five different enzyme classes. Virus-induced gene silencing of a number of these genes resulted in accumulation of pathway intermediates, allowing gene function to be linked to noscapine synthesis and a novel biosynthetic pathway to be proposed. The impact of this discovery for breeding new opium poppy varieties for improved production of noscapine will be discussed.