The gene, named STORR, is found only in poppy species which produce morphinans.
The evolution of the STORR gene came about when two other genes, encoding oxidase and reductase enzymes, came together millions of years ago. The consequent gene blend plays a key role in production of morphine.
Scientists hope the finding will enable the breeding of custom poppy varieties, including those that make noscapine, an anti-cancer compound.
The discovery of STORR completes the set of genes needed for genetic engineering of morphine production in microbes like yeast. It remains to be seen if this can compete commercially with plant-based production or not.
Professor Ian Graham, who led the research at the University of York, noted:
“Plants produce an amazing array of natural chemicals. Discovery of this STORR gene fusion provides us with new insight into how poppy plants have evolved to produce the most effective painkillers known to man.”
Scientists made their breakthrough when they identified poppy plants that were not able to produce morphine or codeine but instead accumulated another compound called (S)-reticuline.
Those plants were found to carry mutations in the STORR gene. These mutations cause a roadblock in the pathway to morphine production in poppy plants.
The scientists were able to show that the non-mutated wild type gene can overcome the roadblock, by expressing it in yeast cells.