Stinky cheese, cola, mint cookies, and grape lemonade. No, these are not part of the latest recipe from Woody Harrelson’s new High Times cookbook. In fact, these are true flavor descriptions for several types of marijuana strains, for which researchers at the University of British Columbia (UBC) have just identified several genes responsible for providing these palatable (and sometimes not) traits. Findings from the new study—published recently in PLOS One in an article entitled “Terpene Synthases from Cannabis sativa”—are a key step for the budding legal cannabis industry.
“The goal is to develop well-defined and highly-reproducible cannabis varieties. This is similar to the wine industry, which depends on defined varieties such as chardonnay or merlot for high-value products,” explained senior study investigator Jörg Bohlmann, Ph.D., a professor in the Michael Smith Laboratories at UBC. “Our genomics work can inform breeders of commercial varieties which genes to pay attention to for specific flavor qualities.”
The UBC researchers found almost 30 terpene synthase genes that contribute to diverse flavors in cannabis. Terpenes are a diverse class of organic molecules produced by a variety of plants. They often have a strong odor and are thought to protect the plants that produce them by deterring herbivores and by attracting predators and parasites of herbivores. The substantial number of terpene-producing genes that the researchers found is comparable to similar to genes that help provide the grapevine flavor for the wine industry. The cannabis genes the researchers discovered play a role in producing natural products like limonene, myrcene, and pinene in the plants.
“The limonene compound produces a lemon-like flavor and myrcene produces the dank, earthy flavor characteristic of purple kush,” noted lead study author Judith Booth, a graduate student in Dr. Bohlmann’s laboratory.
Interestingly, the research group also found the gene that produces the signature terpene of cannabis, beta-caryophyllene, which interacts with cannabinoid receptors in human cells—along with other active ingredients in cannabis.
Previous studies have shown that metabolites unique to cannabis are typically found in the trichomes of female plants—fine outgrowths or hair-like appendages on plants. With this knowledge in hand, the UBC researchers took a genomic approach to look for trichome genes that may play a role in the development of these molecules.
“Transcriptome analysis of trichomes of the cannabis hemp variety ‘Finola’ revealed sequences of all stages of terpene biosynthesis,” the authors wrote. “Nine cannabis terpene synthases (CsTPS) were identified in subfamilies TPS-a and TPS-b….Transcripts associated with terpene biosynthesis are highly expressed in trichomes compared to non-resin producing tissues. Knowledge of the CsTPS gene family may offer opportunities for selection and improvement of terpene profiles of interest in different cannabis strains and varieties.”
Dr. Bohlmann noted that the economic potential of a regulated cannabis industry is huge, but a current challenge is that growers are working with a crop that is not well standardized and highly variable for its key natural product profiles. “There is a need for high-quality and consistent products made from well-defined varieties,” he added.
While the UBC team was excited by their recent findings, they did remark that it will be important to examine the extent to which terpene compounds might interact with the cannabinoid compounds such as tetrahydrocannabinol (THC), which confers the medicinal properties of cannabis.