There are numerous products that claim to help grow more potent cannabis. However, the key to unlocking a plant’s potency lies in its biology. Cannabigerolic acid (CBGA) is the mother of all cannabinoids. Along with being a cannabinoid itself, it is also the starting material for cannabidiol (CBD) and tetrahydrocannabinol (THC). This means that a plant’s ability to produce CBGA will limit its overall ability to produce other cannabinoids [1].
In the new cannabis research paper “Hormonal Control of Promoter Activities of Cannabis sativa Prenyltransferase 1 and 4 and Salicylic Acid Mediated Regulation of Cannabinoid Biosynthesis,” scientists tested different plant hormones for their ability to increase CBDA production by upregulating key enzymes. The plant enzymes Cannabis sativa aromatic prenyltransferase 4 (CsPT4) and 1 (CsPT1) and the enzyme promoter beta-glucuronidase (GUS) are key to producing CBGA [1]. A cannabis plant that produces high levels of these enzymes has the potential to have greater cannabinoid potency than a plant with low enzyme production.
Cannabinoids originate from two biological pathways that involve these enzymes:
Polyketide Pathway
- Produces olivetolic acid (OA)
- Together with GPP, OA produces CBGA via catalyzation from CsPT1 and CsPT4
Plastidial 2-C-methyl-D-erythritol 4-phosphate (MEP) Pathway
- Produces geranyl diphosphate (GPP)
- GPP is a precursor to monoterpenes
- GPP is also involved in CBGA production
- Affects plant phenotype
Cannabinoid production is indeed a complex process. In addition to enzymes, it also involves several plant hormones like salicylic acid (SA), gibberellic acid (GA), auxin (NAA), abscisic acid (ABA), cytokinin (trans-Zeatin), ethylene and jasmonic acid (JA) [1]. These hormones play many roles, one of which is stimulating the production of enzymes. Here is a summary of the experiment’s results:
- Cytokinin production in roots is essential for female sex determination
- Ethylene promotes female flower development
- External GA application induced male flower formation on female cannabis plants
- Male plant flowering is inhibited by ABA
- CsPT4 enzyme production is influenced by SA, GA, ABA, cytokinin, and ethylene
- Cytokinin may regulate CsPT4 expression
- SA, GA, ABA, ethylene, and cytokinin activate CsPT4
- CsPT1 enzyme production is influenced by SA, GA, ABA, and auxin
- SA, Auxin, and ABA activate CsPT1 pro
- Both enzymes can be regulated with SA
- SA induces certain cannabinoid biosynthetic pathway genes
Both CsPT1 and CsPT4 are increased during female flower maturation and are associated with glandular trichome development [1]. However, while CsPT4 and CsPT1 both produce CBGA from OA and GPP, CsPT4 is the only enzyme that synthesizes CBGA.
Salicylic Acid plays an important role in the process of synthesizing cannabinoids [1]. It is a plant hormone that responds to a plant’s need for protection from stress and defense from pathogens and herbivores. When a plant senses trouble, Salicylic Acid production is increased to rally the plant’s defenses. Cannabinoids are actually one of these defenses. They are toxic to fungi and bacteria and discourage animals from eating cannabis plants.
Researchers concluded that Salicylic Acid can positively regulate cannabinoid biosynthesis [1]. In their experiment, SA (1mM) was administered to flowering cannabis plants as a root drench. They also found that administering methyl salicylate as a foliar spray resulted in a 47% increase in CBDA content of hemp plants.
References
- Sands, L. B., Haiden, S. R., Ma, Y., & Berkowitz, G. A. (2023). Hormonal control of promoter activities of Cannabis sativa prenyltransferase 1 and 4 and salicylic acid mediated regulation of cannabinoid biosynthesis. Scientific Reports, 13(1), 8620.
https://www.nature.com/articles/s41598-023-35303-4
