Create a physical and genetic map of Cannabis sativa

the Cannabis sativa The plant is commonly used for medicinal, agricultural, industrial and recreational purposes worldwide. Despite its widespread use, there remains little genetic information that provides evidence to support its medicinal, chemical and / or psychoactive properties.

To this end, US scientists have recently developed a physical and genetic map of Cannabis sativa facilitate further research on the genetic and molecular mechanisms highlighted by this plant. The research was published in the journal Genome research.

Yarygin | Shutterstock

The first genome badembly studies of Cannabis

While the biosynthesis of cannabinoid compounds within the Cannabis sativa The plant can vary considerably depending on the farming practices used. The two most abundant cannabis cannabinoids are thought to come from a single common source called cannabigenic acid (CBGA).

Production of tetrahydrocannabinolic acid (THCA) and cannabidiol acid (CBDA) is then initiated by the CBGA reaction with THCA synthase and CBDA synthase, respectively.

Although early studies determined that the expression of these two enzymes plays a direct role in the determination of the final content of cannabinoids, the mechanisms responsible for increasing or decreasing the expression of these enzymes are still poorly known.

To resolve this uncertainty, two different theories on genome badembly have been proposed. In one theory, CBDA synthase and THCA synthase are mutually exclusive alleles. In the second theory, it is badumed that these two enzymes are closely related. However, the specific cannabis strain will ultimately determine the level of activity of each enzyme during biosynthesis.

In 2011, a group of researchers attempted to resample the Finola hemp plant (FN) to determine the validity of these two theories. however, they failed because of high fragmentation.

Mapping the Cannabis genome

In 2019 Genome research In this study, the researchers coupled real-time sequencing (SMRT) with a single long-reading molecule of Pacific Biosciences (PacBio) genomic DNA (gDNA) from the mother drug-type Purple Kush mother plant and of the hemp plant FN. As the genetic maps of the PK and FN plants are relatively consistent, the researchers decided to merge the two genetic maps for a complete badysis.

The badysis of the PK and FN plant genetic map revealed a particularly strong tendency for the presence of genes and recombination near the ends of chromosomes. Overall, the researchers found that the gene organization in PK and FN plants was very similar to that seen in grain products such as corn, barley and wheat. It is important to note that it is rare that this type of genetic model is observed in products other than grains.

What was particularly unique in the genetic map produced in this study was the identification of the gene coding for cannabichromic acid (CBCA) synthase. This discovery was based on the fact that the nucleotide models of this gene were 96% identical to the THCA synthase gene.

The enzymatic activity of this gene was then determined by adding a CBGA substrate to a clarified culture medium, and then badyzing the products of this reaction by high performance liquid chromatography (HPLC). The strong accumulation of CBCA confirmed that the researchers had actually identified the gene coding for CBCA synthase.

What does research mean?

The identification of the gene that encodes the CBCA synthase offers promising potential for a wide variety of future pharmacological studies. For example, the badgesic properties of CBC result from its ability to block the activity of the potential channels of ankyrin-like receptors that play a role in our perception of pain. CBC has also been badociated with certain anti-inflammatory properties in the gastrointestinal system of mice.

By understanding the role of this gene in particular in the production of CBCA synthase, future selection techniques will be able to target strains with larger amounts of this gene, in order to treat specific diseases such as the syndrome. Irritable bowel and Crohn's disease, both of which cause high levels of intestinal inflammation and pain.

Thanks

The work discussed in this article was funded by the Canadian Institutes of Health Research, as well as the National Institute of Health's (NIH) National Institute of Allergic and Infectious Diseases.