Abstract:Summary
Demand for cannabidiol (CBD), the predominant cannabinoid in hemp (Cannabis sativa), has favored cultivars producing unprecedented quantities of CBD. We investigated the ancestry of a new cultivar and cannabinoid synthase genes in relation to cannabinoid inheritance.
A nanopore‐based assembly anchored to a high‐resolution linkage map provided a chromosome‐resolved genome for CBDRx, a potent CBD‐type cultivar. We measured cannabinoid synthase expression by cDNA sequencing and conducted a population ge… Show more
“…Meanwhile, all the published marijuana-type plants cluster separately (Supplementary Figure 4). These results match prior published data, where CBD-type hemp plants are usually genetically distinct from marijuana (Sawler et al, 2015;Lynch et al, 2016;Grassa et al, 2021).…”
High consumer demand for cannabidiol (CBD) has made high-CBD hemp (Cannabis sativa) an extremely high-value crop. However, high demand has resulted in the industry developing faster than the research, resulting in the sale of many hemp accessions with inconsistent performance and chemical profiles. These inconsistencies cause significant economic and legal problems for growers interested in producing high-CBD hemp. To determine the genetic and phenotypic consistency in available high-CBD hemp varieties, we obtained seed or clones from 22 different named accessions meant for commercial production. Genotypes (∼48,000 SNPs) and chemical profiles (% CBD and THC by dry weight) were determined for up to 8 plants per accession. Many accessions–including several with the same name–showed little consistency either genetically or chemically. Most seed-grown accessions also deviated significantly from their purported levels of CBD and THC based on the supplied certificates of analysis. Several also showed evidence of an active tetrahydrocannabinolic acid (THCa) synthase gene, leading to unacceptably high levels of THC in female flowers. We conclude that the current market for high-CBD hemp varieties is highly unreliable, making many purchases risky for growers. We suggest options for addressing these issues, such using unique names and developing seed and plant certification programs to ensure the availability of high-quality, verified planting materials.
“…Meanwhile, all the published marijuana-type plants cluster separately (Supplementary Figure 4). These results match prior published data, where CBD-type hemp plants are usually genetically distinct from marijuana (Sawler et al, 2015;Lynch et al, 2016;Grassa et al, 2021).…”
High consumer demand for cannabidiol (CBD) has made high-CBD hemp (Cannabis sativa) an extremely high-value crop. However, high demand has resulted in the industry developing faster than the research, resulting in the sale of many hemp accessions with inconsistent performance and chemical profiles. These inconsistencies cause significant economic and legal problems for growers interested in producing high-CBD hemp. To determine the genetic and phenotypic consistency in available high-CBD hemp varieties, we obtained seed or clones from 22 different named accessions meant for commercial production. Genotypes (∼48,000 SNPs) and chemical profiles (% CBD and THC by dry weight) were determined for up to 8 plants per accession. Many accessions–including several with the same name–showed little consistency either genetically or chemically. Most seed-grown accessions also deviated significantly from their purported levels of CBD and THC based on the supplied certificates of analysis. Several also showed evidence of an active tetrahydrocannabinolic acid (THCa) synthase gene, leading to unacceptably high levels of THC in female flowers. We conclude that the current market for high-CBD hemp varieties is highly unreliable, making many purchases risky for growers. We suggest options for addressing these issues, such using unique names and developing seed and plant certification programs to ensure the availability of high-quality, verified planting materials.
“…3B ) that either map both genes and the CBDAS pseudogenes or map THCAS and the CBDAS pseudogenes. The main pattern inferred from our comparative analysis confirms previous structural data based on full genome sequencing of single cultivars ( 18 , 19 ). It is also consistent with published chemotype inheritance models validated among a wide variety of Cannabis accessions ( 16 , 17 , 20 , 43 , 44 ), thus providing complementary evidence for the latter at the genomic sequence level and global validation across a comprehensive panel of Cannabis domestication types distributed worldwide.…”
Section: Resultssupporting
confidence: 87%
“…3B) that either map both genes and the CBDAS pseudogenes or map THCAS and the CBDAS pseudogenes. The main pattern inferred from our comparative analysis confirms previous structural data based on full genome sequencing of single cultivars (18,19). It is also consistent with published chemotype inheritance models validated among a wide variety of Cannabis accessions (16,17,20,43,44) As such, the results call into question, from both a biological and functional point of view, the current binary categorization of Cannabis plants as "hemp" or "marijuana" derived from the assignment to a single phenotype [see also (20)].…”
Section: Loss Of Function Of the Two Main Cannabinoid Synthase Genes During Domesticationsupporting
confidence: 88%
“…When involved in secondary metabolism, the homologs of these genes likely play a major role in chemical plant defense (8). Confirming earlier genetic studies, recent genome assemblies showed that CBDAS and THCAS (and their multiple pseudogenic copies) lie scattered within closely linked loci, in a retrotransposon-rich, highly repetitive region of the genome with suppressed recombination, and with a history of extensive rearrangement and tandem duplication/pseudogenization events (4,(16)(17)(18)(19). Using strict filtering criteria, we mapped the reads of the 104 analyzed genomes to a reference CBDA/THCA hybrid cultivar genome [Jamaican Lion DASH (42)], in which full-length coding sequences for THCAS, CBDAS, and more than 30 pseudogene copies of these genes are assembled.…”
Section: Loss Of Function Of the Two Main Cannabinoid Synthase Genes During Domesticationmentioning
confidence: 64%
“…1A and table S1). After mapping to the reference CBDRx genome ( 18 ), we identified 12,010,905 putative single-nucleotide polymorphisms (SNPs) that passed filtering criteria across the 104 Cannabis accessions retained for subsequent analyses (fig. S1; see Materials and Methods).…”
Cannabis sativa has long been an important source of fiber extracted from hemp and both medicinal and recreational drugs based on cannabinoid compounds. Here, we investigated its poorly known domestication history using whole-genome resequencing of 110 accessions from worldwide origins. We show that C. sativa was first domesticated in early Neolithic times in East Asia and that all current hemp and drug cultivars diverged from an ancestral gene pool currently represented by feral plants and landraces in China. We identified candidate genes associated with traits differentiating hemp and drug cultivars, including branching pattern and cellulose/lignin biosynthesis. We also found evidence for loss of function of genes involved in the synthesis of the two major biochemically competing cannabinoids during selection for increased fiber production or psychoactive properties. Our results provide a unique global view of the domestication of C. sativa and offer valuable genomic resources for ongoing functional and molecular breeding research.
Cannabis sativais an extraordinarily versatile species. Hemp and its cousin marijuana, bothC. sativa, have been used for millennia as a source of fibre, oil, and for medicinal, spiritual, and recreational purposes. Because the consumption ofCannabiscan have psychoactive effects, the plant has been widely banned throughout the last century. In the past decade, evidence of its medicinal properties did lead to the relaxation of legislation in many countries around the world. Consequently, the genetics and development ofCannabisas well asCannabis‐derived products are the subject of renewed attention.Here, we review the biology ofC. sativa,including recent insights from taxonomy, morphology, and genomics, with an emphasis on the genetics of cannabinoid synthesis. Because the femaleCannabisflower is of special interest as the site of cannabinoid synthesis, we explore flower development, flowering time well as the species' unique sex determination system in detail.Furthermore, we outline the tremendous medicinal, engineering, and environmental opportunities thatCannabisbears. Together, the picture emerges that our understanding ofCannabisbiology currently progresses at an unusual speed. A future challenge will be to preserve the multi‐purpose nature ofCannabis, and to harness its medicinal properties and sustainability advantages simultaneously.
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