From Cannabis Evolution and Ethnobotany by Clarke and Merlin:
“Biotechnology in the form of genetic modification has also reached Cannabis. An Irish research group successfully transferred genes for grey mold resistance to an industrial hemp variety (Clarke and Watson 2007). Grey mold is one of the leading pests of Cannabis, causing crop loss and contaminating medical supplies, and the transfer of resistance into medical varieties would therefore be of great value.
Yukihiro Shoyama and colleagues at Fukuoka University in Japan have transferred the THC-synthase gene from Cannabis to tobacco (Nicotiana tobaccum) and induced it to convert CBG (cannabigerol, the precursor molecule to THC) into THC (Shoyama et al. 2001).
Other agronomically valuable traits may also be transferred to Cannabis such as enhanced pest resistance, increased yields of medically valuable compounds, tolerance of environmental extremes, and sexual sterility.
The reaction to development and release of genetically modified (GM) organisms has been guarded. Cannabis presents a particularly high risk of transmitting GM genes to industrial hemp crops and weedy Cannabis because it is wind pollinated.
The EU has installed strict regulations to prevent the accidental release of GM genes, and therefore production of GM Cannabis in the EU may prove impractical. However, nonfood industrial fiber and pharmaceutical cultivars may not receive as much resistance from consumers and environmentalists as food crops.
For example, genes coding for cannabinoid biosynthesis might also be transferred from Cannabis to less politically sensitive organisms than tobacco. However, expression of THC synthesis in a widely distributed plant may also present a new set of obstacles to law enforcement.
On the other hand, transferring cannabinoid synthesis systems from Cannabis into other genera of plants, fungi, and bacteria opens up the possibility of producing medically valuable cannabinoids in industrial fermenters and circumventing Cannabis growing altogether.” [that’s called precision fermentation. RR]