Gene Networks Underlying Cannabinoid and Terpenoid Accumulation in Cannabis

Abstract

Glandular trichomes are specialized anatomical structures that accumulate secretions with important biological roles in plantenvironment interactions. These secretions also have commercial uses in the flavor, fragrance, and pharmaceutical industries. The capitate-stalked glandular trichomes of Cannabis sativa (cannabis), situated on the surfaces of the bracts of the female flowers, are the primary site for the biosynthesis and storage of resins rich in cannabinoids and terpenoids. In this study, we profiled nine commercial cannabis strains with purportedly different attributes, such as taste, color, smell, and genetic origin. Glandular trichomes were isolated from each of these strains, and cell type-specific transcriptome data sets were acquired. Cannabinoids and terpenoids were quantified in flower buds. Statistical analyses indicated that these data sets enable the high-resolution differentiation of strains by providing complementary information. Integrative analyses revealed a coexpression network of genes involved in the biosynthesis of both cannabinoids and terpenoids from imported precursors. Terpene synthase genes involved in the biosynthesis of the major monoterpenes and sesquiterpenes routinely assayed by cannabis testing laboratories were identified and functionally evaluated. In addition to cloning variants of previously characterized genes, specifically CsTPS14CT [(2)-limonene synthase] and CsTPS15CT (b-myrcene synthase), we functionally evaluated genes that encode enzymes with activities not previously described in cannabis, namely CsTPS18VF and CsTPS19BL (nerolidol/linalool synthases), CsTPS16CC (germacrene B synthase), and CsTPS20CT (hedycaryol synthase). This study lays the groundwork for developing a better understanding of the complex chemistry and biochemistry underlying resin accumulation across commercial cannabis strains.

Grinding and Fractionation during Distillation Alter Hemp Essential Oil Profile and Its Antimicrobial Activity

“…CS (Carmagnola Selezionata) was 5–6% [ 17 ]. Myrcene in the drug-type hemp (marijuana) tissue was relatively low, (0.7–4.3%) in female flower buds [ 34 ], and it was 1% in the marijuana EO [ 31 ].…”

“…Limonene, monocyclic monoterpene, is found in all types of hemp, it is one of the signature compounds in marijuana headspace [ 33 ]. For example, limonene concentration in drug-type hemp varied between 0.03 and 1.53% [ 34 ], the sum of limonene and β -phellandrene was reported to be 1% of marijuana EO [ 31 ].…”

“…β -Caryophyllene, bicyclic sesquiterpene, is one of the major hemp EO constituents, be it from industrial hemp (grain and fiber) [ 38 ], US strains grown for non-psychoactive cannabinoids such as CBD and CBG [ 29 ], or in the drug-type (marijuana strains) [ 34 , 45 ]. This study demonstrated that while the concentration of β -caryophyllene was 8–10% in the control hemp EO; a 20% β -caryophyllene rich EO can be produced by collecting the EO in the 80–120 DT.…”

“…The total amount of monoterpenes in the EO of other hemps from the same region was reported to be from n.d. in two wild hemps to 8.0% in other wild hemps, and 1.4–13.5% in eight registered hemp cultivars [ 29 ]. Total monoterpenes in nine drug-type varieties of hemp were 0.5–8.4% in dry flowers [ 34 ], however, this cannot be readily related to their potential concentration in the EO.…”

A Single Nucleotide Polymorphism assay sheds light on the extent and distribution of genetic diversity, population structure and functional basis of key traits in cultivated North American Cannabis

“…Integrative analyses revealed a co-expression network of genes involved in the biosynthesis of both cannabinoids and terpenoids from common precursors (Zager et al, 2019). As such, we searched for signals underlying the within resin type cannabis clustering which can be differentiated by the dominant terpene expression, often under the control of two dozen terpene synthase genes (TPS; Allen et al, 2019).…”