Recent advances in Cannabis sativa genomics research

Abstract

Summary Cannabis (Cannabis sativa L.) is one of the oldest cultivated plants purported to have unique medicinal properties. However, scientific research of cannabis has been restricted by the Single Convention on Narcotic Drugs of 1961, an international treaty that prohibits the production and supply of narcotic drugs except under license. Legislation governing cannabis cultivation for research, medicinal and even recreational purposes has been relaxed recently in certain jurisdictions. As a result, there is now potential to accelerate cultivar development of this multi‐use and potentially medically useful plant species by application of modern genomics technologies. Whilst genomics has been pivotal to our understanding of the basic biology and molecular mechanisms controlling key traits in several crop species, much work is needed for cannabis. In this review we provide a comprehensive summary of key cannabis genomics resources and their applications. We also discuss prospective applications of existing and emerging genomics technologies for accelerating the genetic improvement of cannabis.

Accumulation of somatic mutations leads to genetic mosaicism in Cannabis

“…In comparison, the long-lived oak study only called 5,330 potential SNVs that had accumulated over many years (Schmid-Siegert et al ., 2017). Interestingly, the Napoleon Oak genome was less than 1% heterozygous while the cannabis genome is known to be highly heterozygous (estimated at 12.5 – 40.5%) and contains substantial amounts of repetitive elements (estimated at 70%) (Hurgobin et al ., 2020). We identified somatic mutations with deep sequencing (>50x depth of coverage) and used systematic filtering steps to reduce errors that may have occurred from next-generation sequencing (NGS) and incorrect mapping (Ajay et al ., 2011).…”

“…The sequencing was performed on an Illumina NovaSeq 6000 platform at the McGill University-Génome Québec Innovation Center in Montreal, QC, Canada generating >1 billion 150-bp paired-end reads. to provide >50x death of coverage by sequencing reads against the mapped the public domain C. sativa reference genome (cs10 v. 2.0; Hurgobin et al ., 2020)…”

“…The main pharmaceutical and psychoactive compounds are cannabinoids that accumulate in trichomes produced primarily on floral tissues of female plants (van Bakel et al ., 2011). To date, 177 cannabinoids have been identified and described, with the two most naturally abundant, well-studied, and sought after being (−)- trans -Δ 9 –tetrahydrocannabinol (THC) and cannabidiol (CBD) (Hanuš and Hod, 2020; Hurgobin et al ., 2020). These compounds have many demonstrated therapeutic properties, including alleviating symptoms in epilepsy (Devinsky et al ., 2014) and multiple sclerosis (van Amerongen et al ., 2018) and are being investigated for other ailments such as Alzheimer’s disease (Watt and Karl, 2017).…”

“…Additionally, cannabis produces hundreds of different terpenes/terpenoids, which are also known to have therapeutic effects, including antifungal, antiviral, anticancer, anti-inflammatory, antiparasitic, antioxidant, and antimicrobial activities, and are thought to interact with cannabinoids to alter their activities (Hanuš and Hod, 2020). Cannabinoids, terpenes and other secondary metabolites are produced in the capitate stalked glandular trichomes and minor variations in concentrations of each may result in distinct therapeutic effects (Hurgobin et al ., 2020).…”

“…The medicinal effects of Cannabis plants depend on the relative concentration of these compounds and are often classified into three main categories based on the THC:CBD ratio. Type I plants express a well over 1:1 THC:CBD ratio, Type II plants have moderate amounts with a near equal ratio, and Type III plants contain a less than 1:1 ratio (Hurgobin et al ., 2020). However, it should be noted that this is an oversimplification of the chemical diversity found within Cannabis and that each plant has a unique chemical fingerprint that may impact its biological activity.…”