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We report the identification of two single nucleotide polymorphisms in Cannabis saliva L. that are associated with female and male plant sex phenotypes and are located on the top arm of the X chromosome. High resolution melt analysis was used to develop and validate a novel, rapid method for sex identification in medical and (or) recreational cannabis as well as in hemp. This method can distinguish between dioecious male (XY) and dioecious female (XX) cannabis plants with 100% accuracy and can also be used to differentiate between male and female Humulus lupulus L. (hop) plants. Keywords: Cannabis sativa L., hemp, Humulus lupulus L., hops, sex identification, sex-specific SNPs, high resolution melt analysis Les auteurs rapportent l'identification de deux polymorphismes mononucléotidiques chez Cannabis saliva L. qui sont associés aux phénotypes sexuels des plantes femelles et mâles, et qui sont situés sur le bras supérieur du chromosome X. L'analyse par fusion à haute résolution a été utilisée pour développer et valider une nouvelle méthode rapide d'identification du sexe dans le cannabis médical et (ou) récréatif ainsi que dans le chanvre. Cette méthode permet de distinguer les plants de cannabis dioïques mâles (XY) et dioïques femelles (XX) avec une précision de 100%, et peut également être utilisée pour différencier les plants de Humulus lupulus L. (houblon) mâles et femelles. [Traduit par la Rédaction] Mots-clés : Cannabis saliva L., chanvre, Humulus lupulus L., houblon, identification du sexe, SNP spécifiques au sexe, analyse par fusion à haute résolution, Introduction The species Cannabis sativa L. includes both hemp and medicinal and (or) recreational cannabis plant cultivars. For the purposes of this study, we will use the term cannabis to [...]

Cannabis glandular trichomes produce and store an abundance of lipidic specialised metabolites (e.g. cannabinoids and terpenes) that are consumed by humans for medicinal and recreational purposes. Due to a lack of genetic resources and inherent autofluorescence of cannabis glandular trichomes, our knowledge of cannabinoid trafficking and secretion is limited to transmission electron microscopy (TEM). Advances in cryofixation methods has resulted in ultrastructural observations closer to the 'natural state' of the living cell, and recent reports of cryofixed cannabis trichome ultrastructure challenge the long‐standing model of cannabinoid trafficking proposed by ultrastructural reports using chemically fixed samples. Here, we compare the ultrastructural morphology of cannabis glandular trichomes preserved using conventional chemical fixation and ultrarapid cryofixation. We show that chemical fixation results in amorphous metabolite inclusions surrounding the organelles of glandular trichomes that were not present in cryofixed samples. Vacuolar morphology in cryofixed samples exhibited homogenous electron density, while chemically fixed samples contained a flocculent electron dense periphery and electron lucent lumen. In contrast to the apparent advantages of cryopreservation, fine details of cell wall fibre orientation could be observed in chemically fixed glandular trichomes that were not seen in cryofixed samples. Our data suggest that chemical fixation results in intracellular artefacts that impact the interpretation of lipid production and trafficking, while enabling greater detail of extracellular polysaccharide organisation. LAY DESCRIPTION: For millennia humans have grown and consumed cannabis flowers for use in traditional medicine and intoxication, due to the plant's active ingredients called cannabinoids. The most well‐known cannabinoid is tetrahydrocannabidiol (THC). Despite this long history, and recent relaxation of cannabis uses for medicinal and recreational consumption in many parts of the world, little is known about how the plant makes the cannabinoids in its cells. Small mushroom‐shaped structures on the flower surface, called glandular trichomes, produce and store the cannabinoids. To image inside the cells of THC‐rich cannabis flowers, it is necessary to use electron microscopy, and this has revealed complex internal membrane networks and specialised cell structures in these tiny biofactories. In this study, we explored different ways to preserve the cannabis glandular trichomes for electron microscopy, using either cryogenic preservation or chemical crosslinking, in order to determine the benefits and drawbacks of each method. The chemical crosslinking method produced dramatic re‐arrangement of cell contents that were not seen in the cryofixation, where the near‐instantaneous immobilisation of the cell structure led to exceptional preservation of the THC‐producing cells. Despite the benefits of using cryofixation for preserving the complex cell structures, it was not as useful for seeing details of the cell walls surrounding the glandular trichome. Together, our data show stark differences in cannabis glandular trichome cell structure that result from cryofixation and chemical fixation. This is important because the chemical fixation protocol was historically used and informed previous models of cannabinoid production and trafficking. Cryofixation produces exciting new models of THC production in cannabis, due to its high‐fidelity preservation of cell structures. In contrast, studies of cell walls may still benefit from the traditional chemical cross‐linking technique of sample preservation for electron microscopy. https://www.cell.com/current‐biology/fulltext/S0960‐9822(22)01115‐0 [ABSTRACT FROM AUTHOR]

The valuable cannabinoid and terpenoid metabolites of Cannabis sativa L. are produced by floral glandular trichomes. The trichomes consist of secretory disk cells, which produce the abundant lipidic metabolites, and an extracellular storage cavity. The mechanisms of apoplastic cavity formation to accumulate and store metabolites in cannabis glandular trichomes remain wholly unexplored. Here, we identify key wall components and how they change during cannabis trichome development. While glycome and monosaccharide analyses revealed that glandular trichomes have loosely bound xyloglucans and pectic polysaccharides, quantitative immunolabeling with wall-directed antibodies revealed precise spatiotemporal distributions of cell wall epitopes. An epidermal-like identity of early trichome walls matured into specialized wall domains over development. Cavity biogenesis was marked by separation of the subcuticular wall from the underlying surface wall in a homogalacturonan and α-1,5 arabinan epitope-rich zone and was associated with a reduction in fucosylated xyloglucan epitopes. As the cavity filled, a matrix with arabinogalactan and α-1,5 arabinan epitopes enclosed the metabolite droplets. At maturity, the disk cells' apical wall facing the storage cavity accumulated rhamnogalacturonan-I epitopes near the plasma membrane. Together, these data indicate that cannabis glandular trichomes undergo spatiotemporal remodeling at specific wall subdomains to facilitate storage cavity formation and metabolite storage. [ABSTRACT FROM AUTHOR]

Abstract Background Bitter acids (e.g. humulone) are prenylated polyketides synthesized in lupulin glands of the hop plant (Humulus lupulus) which are important contributors to the bitter flavour and stability of beer. Bitter acids are formed from acyl-CoA precursors derived from branched-chain amino acid (BCAA) degradation and C5 prenyl diphosphates from the methyl-D-erythritol 4-phosphate (MEP) pathway. We used RNA sequencing (RNA-seq) to obtain the transcriptomes of isolated lupulin glands, cones with glands removed and leaves from high α-acid hop cultivars, and analyzed these datasets for genes involved in bitter acid biosynthesis including the supply of major precursors. We also measured the levels of BCAAs, acyl-CoA intermediates, and bitter acids in glands, cones and leaves. Results Transcripts encoding all the enzymes of BCAA metabolism were significantly more abundant in lupulin glands, indicating that BCAA biosynthesis and subsequent degradation occurs in these specialized cells. Branched-chain acyl-CoAs and bitter acids were present at higher levels in glands compared with leaves and cones. RNA-seq analysis showed the gland-specific expression of the MEP pathway, enzymes of sucrose degradation and several transcription factors that may regulate bitter acid biosynthesis in glands. Two branched-chain aminotransferase (BCAT) enzymes, HlBCAT1 and HlBCAT2, were abundant, with gene expression quantification by RNA-seq and qRT-PCR indicating that HlBCAT1 was specific to glands while HlBCAT2 was present in glands, cones and leaves. Recombinant HlBCAT1 and HlBCAT2 catalyzed forward (biosynthetic) and reverse (catabolic) reactions with similar kinetic parameters. HlBCAT1 is targeted to mitochondria where it likely plays a role in BCAA catabolism. HlBCAT2 is a plastidial enzyme likely involved in BCAA biosynthesis. Phylogenetic analysis of the hop BCATs and those from other plants showed that they group into distinct biosynthetic (plastidial) and catabolic (mitochondrial) clades. Conclusions Our analysis of the hop transcriptome significantly expands the genomic resources available for this agriculturally-important crop. This study provides evidence for the lupulin gland-specific biosynthesis of BCAAs and prenyl diphosphates to provide precursors for the production of bitter acids. The biosynthetic pathway leading to BCAAs in lupulin glands involves the plastidial enzyme, HlBCAT2. The mitochondrial enzyme HlBCAT1 degrades BCAAs as the first step in the catabolic pathway leading to branched chain-acyl-CoAs.

Abstract Background Virus-induced gene silencing (VIGS) has emerged as a method for performing rapid loss-of-function experiments in plants. Despite its expanding use, the effect of host gene insert length and other properties on silencing efficiency have not been systematically tested. In this study, we probed the optimal properties of cDNA fragments of the phytoene desaturase (PDS) gene for efficient VIGS in Nicotiana benthamiana using tobacco rattle virus (TRV). Results NbPDS inserts of between 192 bp and 1304 bp led to efficient silencing as determined by analysis of leaf chlorophyll a levels. The region of the NbPDS cDNA used for silencing had a small effect on silencing efficiency with 5' and 3' located inserts performing more poorly than those from the middle. Silencing efficiency was reduced by the inclusion of a 24 bp poly(A) or poly(G) homopolymeric region. We developed a method for constructing cDNA libraries for use as a source of VIGS-ready constructs. Library construction involved the synthesis of cDNA on a solid phase support, digestion with RsaI to yield short cDNA fragments lacking poly(A) tails and suppression subtractive hybridization to enrich for differentially expressed transcripts. We constructed two cDNA libraries from methyl-jasmonate treated N. benthamiana roots and obtained 2948 ESTs. Thirty percent of the cDNA inserts were 401–500 bp in length and 99.5% lacked poly(A) tails. To test the efficiency of constructs derived from the VIGS-cDNA libraries, we silenced the nicotine biosynthetic enzyme, putrescine N-methyltransferase (PMT), with ten different VIGS-NbPMT constructs ranging from 122 bp to 517 bp. Leaf nicotine levels were reduced by more than 90% in all plants infected with the NbPMT constructs. Conclusion Based on the silencing of NbPDS and NbPMT, we suggest the following design guidelines for constructs in TRV vectors: (1) Insert lengths should be in the range of ~200 bp to ~1300 bp, (2) they should be positioned in the middle of the cDNA and (3) homopolymeric regions (i.e. poly(A/T) tails) should not be included. Our VIGS-cDNA library method, which incorporates these guidelines to produce sequenced, VIGS-ready cDNAs, will be useful for both fast-forward and reverse genetics experiments in TRV vectors.

Summary: The cannabis leaf is iconic, but it is the flowers of cannabis that are consumed for the psychoactive and medicinal effects of their specialized metabolites. Cannabinoid metabolites, together with terpenes, are produced in glandular trichomes. Superficially, stalked and sessile trichomes in cannabis only differ in size and whether they have a stalk. The objectives of this study were: to define each trichome type using patterns of autofluorescence and secretory cell numbers, to test the hypothesis that stalked trichomes develop from sessile‐like precursors, and to test whether metabolic specialization occurs in cannabis glandular trichomes. A two‐photon microscopy technique using glandular trichome intrinsic autofluorescence was developed which demonstrated that stalked glandular trichomes possessed blue autofluorescence correlated with high cannabinoid levels. These stalked trichomes had 12–16 secretory disc cells and strongly monoterpene‐dominant terpene profiles. In contrast, sessile trichomes on mature flowers and vegetative leaves possessed red‐shifted autofluorescence, eight secretory disc cells and less monoterpene‐dominant terpene profiles. Moreover, intrinsic autofluorescence patterns and disc cell numbers supported a developmental model where stalked trichomes develop from apparently sessile trichomes. Transcriptomes of isolated floral trichomes revealed strong expression of cannabinoid and terpene biosynthetic genes, as well as uncharacterized genes highly co‐expressed with CBDA synthase. Identification and characterization of two previously unknown and highly expressed monoterpene synthases highlighted the metabolic specialization of stalked trichomes for monoterpene production. These unique properties and highly expressed genes of cannabis trichomes determine the medicinal, psychoactive and sensory properties of cannabis products. Significance Statement: The unique monoterpene‐rich cannabis stalked trichomes that determine the medicinal, psychoactive and sensory properties of cannabis flowers develop from sessile‐like intermediates. [ABSTRACT FROM AUTHOR]

Cannabis (Cannabis sativa) plants produce and accumulate a terpene-rich resin in glandular trichomes, which are abundant on the surface of the female inflorescence. Bouquets of different monoterpenes and sesquiterpenes are important components of cannabis resin as they define some of the unique organoleptic properties and may also influence medicinal qualities of different cannabis strains and varieties. Transcriptome analysis of trichomes of the cannabis hemp variety ‘Finola’ revealed sequences of all stages of terpene biosynthesis. Nine cannabis terpene synthases (CsTPS) were identified in subfamilies TPS-a and TPS-b. Functional characterization identified mono- and sesqui-TPS, whose products collectively comprise most of the terpenes of ‘Finola’ resin, including major compounds such as β-myrcene, (E)-β-ocimene, (-)-limonene, (+)-α-pinene, β-caryophyllene, and α-humulene. Transcripts associated with terpene biosynthesis are highly expressed in trichomes compared to non-resin producing tissues. Knowledge of the CsTPS gene family may offer opportunities for selection and improvement of terpene profiles of interest in different cannabis strains and varieties. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA) is a well-characterized plant hormone, known to mediate developmental aspects as well as both abiotic and biotic stress responses. Notably, the exogenous application of ABA has recently been shown to increase susceptibility to the fungal pathogen Fusarium graminearum, the causative agent of Fusarium head blight (FHB) in wheat and other cereals. However roles and mechanisms associated with ABA’s modulation of pathogen responses remain enigmatic. Here the identification of putative ABA receptors from available genomic databases for Triticum aestivum (bread wheat) and Brachypodium distachyon (a model cereal) are reported. A number of these were cloned for recombinant expression and their functionality as ABA receptors confirmed by in vitro assays against protein phosphatases Type 2Cs. Ligand selectivity profiling of one of the wheat receptors (Ta_PYL2DS_FL) highlighted unique activities compared to Arabidopsis AtPYL5. Mutagenic analysis showed Ta_PYL2DS_FL amino acid D180 as being a critical contributor to this selectivity. Subsequently, a virus induced gene silencing (VIGS) approach was used to knockdown wheat Ta_PYL4AS_A (and similar) in planta, yielding plants with increased early stage resistance to FHB progression and decreased mycotoxin accumulation. Together these results confirm the existence of a family of ABA receptors in wheat and Brachypodium and present insight into factors modulating receptor function at the molecular level. That knockdown of Ta_PYL4AS_A (and similar) leads to early stage FHB resistance highlights novel targets for investigation in the future development of disease resistant crops. [ABSTRACT FROM AUTHOR]

Despite its cultivation as a source of food, fibre and medicine, and its global status as the most used illicit drug, the genus Cannabis has an inconclusive taxonomic organization and evolutionary history. Drug types of Cannabis (marijuana), which contain high amounts of the psychoactive cannabinoid Δ9-tetrahydrocannabinol (THC), are used for medical purposes and as a recreational drug. Hemp types are grown for the production of seed and fibre, and contain low amounts of THC. Two species or gene pools (C. sativa and C. indica) are widely used in describing the pedigree or appearance of cultivated Cannabis plants. Using 14,031 single-nucleotide polymorphisms (SNPs) genotyped in 81 marijuana and 43 hemp samples, we show that marijuana and hemp are significantly differentiated at a genome-wide level, demonstrating that the distinction between these populations is not limited to genes underlying THC production. We find a moderate correlation between the genetic structure of marijuana strains and their reported C. sativa and C. indica ancestry and show that marijuana strain names often do not reflect a meaningful genetic identity. We also provide evidence that hemp is genetically more similar to C. indica type marijuana than to C. sativa strains. [ABSTRACT FROM AUTHOR]

Background: Virus-induced gene silencing (VIGS) has emerged as a method for performing rapid loss-of-function experiments in plants. Despite its expanding use, the effect of host gene insert length and other properties on silencing efficiency have not been systematically tested. In this study, we probed the optimal properties of cDNA fragments of the phytoene desaturase (PDS) gene for efficient VIGS in Nicotiana benthamiana using tobacco rattle virus (TRV). Results: NbPDS inserts of between 192 bp and 1304 bp led to efficient silencing as determined by analysis of leaf chlorophyll a levels. The region of the NbPDS cDNA used for silencing had a small effect on silencing efficiency with 5' and 3' located inserts performing more poorly than those from the middle. Silencing efficiency was reduced by the inclusion of a 24 bp poly(A) or poly(G) homopolymeric region. We developed a method for constructing cDNA libraries for use as a source of VIGS-ready constructs. Library construction involved the synthesis of cDNA on a solid phase support, digestion with RsaI to yield short cDNA fragments lacking poly(A) tails and suppression subtractive hybridization to enrich for differentially expressed transcripts. We constructed two cDNA libraries from methyl-jasmonate treated N. benthamiana roots and obtained 2948 ESTs. Thirty percent of the cDNA inserts were 401-500 bp in length and 99.5% lacked poly(A) tails. To test the efficiency of constructs derived from the VIGS-cDNA libraries, we silenced the nicotine biosynthetic enzyme, putrescine N-methyltransferase (PMT), with ten different VIGS-NbPMT constructs ranging from 122 bp to 517 bp. Leaf nicotine levels were reduced by more than 90% in all plants infected with the NbPMT constructs. Conclusion: Based on the silencing of NbPDS and NbPMT, we suggest the following design guidelines for constructs in TRV vectors: (1) Insert lengths should be in the range of ~200 bp to ~1300 bp, (2) they should be positioned in the middle of the cDNA and (3) homopolymeric regions (i.e. poly(A/T) tails) should not be included. Our VIGS-cDNA library method, which incorporates these guidelines to produce sequenced, VIGS-ready cDNAs, will be useful for both fast-forward and reverse genetics experiments in TRV vectors. [ABSTRACT FROM AUTHOR]

Xanthohumol (3′-[3,3-dimethyl allyl]-2′,4′,4-trihydroxy-6′-methoxychalcone) is the principal prenylated flavonoid of the female inflorescences of the hop plant (`hops''), an ingredient of beer. Human exposure to xanthohumol and related prenylflavonoids, such as 8-prenylnaringenin and isoxanthohumol, is primarily through beer consumption. Xanthohumol has been characterized a `broad-spectrum'' cancer chemopreventive agent in in vitro studies, while 8-prenylnaringenin enjoys fame as the most potent phytoestrogen known to date. These biological activities suggest that prenylflavonoids from hops have potential for application in cancer prevention programs and in prevention or treatment of (post-)menopausal `hot flashes'' and osteoporosis. Xanthohumol and 8-prenylnaringenin are metabolized into many flavonoid derivatives with modified 3,3-dimethyl allyl (prenyl) moieties. Xanthohumol is formed in lupulin glands by a specialized branch of flavonoid biosynthesis that involves prenylation and O-methylation of the polyketide intermediate chalconaringenin. Although a lupulin gland-specific chalcone synthase is known, the aromatic prenyltransferase and O-methyltransferase participating in xanthohumol have not been identified. The prenylflavonoid pathway is a possible target for breeding or biotechnological modification of hops with the aim of increasing xanthohumol levels for beer brewing and 8-prenylnaringenin levels for pharmaceutical production. [Copyright &y& Elsevier]

A cDNA encoding a stilbene synthase, RtSTS, was isolated from the rhizomes of Tatar rhubarb, Rheum tataricum L. (Polygonaceae), a medicinal plant containing stilbenes and other polyketides. Recombinant RtSTS was expressed in E. coli and assayed with acetyl-coenzyme A (CoA), n-butyryl-CoA, isovaleryl-CoA, n-hexanoyl-CoA, cinnamoyl-CoA and p-coumaroyl-CoA as primers of polyketide synthesis. RtSTS synthesized resveratrol and a trace amount of naringenin chalcone from p-coumaroyl-CoA, supporting the enzyme''s identification as a resveratrol-type stilbene synthase (EC 2.3.1.95). Bis-noryangonin and p-coumaroyl triacetic acid lactone (CTAL)-type pyrones were observed in minor amounts in the reaction with p-coumaroyl-CoA and as major products with cinnamoyl CoA. As well, such pyrones, and not aromatic polyketides, were identified as the only products in assays with aliphatic and benzoyl CoA esters. Acetonyl-4-hydroxy-2-pyrone, a pyrone synthesized from acetyl-CoA, was identified as a new product of a stilbene synthase. Using Northern blot analysis, RtSTS transcript was found to be highly expressed in R. tataricum rhizomes, with low transcript levels also present in young leaves. This expression pattern correlated with the occurrence of resveratrol, which was detected in higher amounts in R. tataricum rhizomes compared with leaves and petioles using HPLC. Few stilbene synthases have been found in plants, and the identification of RtSTS provides additional sequence and catalytic information with which to study the evolution of plant polyketide synthases. [Copyright &y& Elsevier]

For centuries, humans have cultivated cannabis for the pharmacological properties that result from consuming its specialized metabolites, primarily cannabinoids and terpenoids. Today, cannabis is a multi-billion-dollar industry whose existence rests on the biological activity of tiny cell clusters, called glandular trichomes, found mainly on flowers. Cannabinoids are toxic to cannabis cells,1 and how the trichome cells can produce and secrete massive quantities of lipophilic metabolites is not known. 1 To address this gap in knowledge, we investigated cannabis glandular trichomes using ultra-rapid cryofixation, quantitative electron microscopy, and immuno-gold labeling of cannabinoid pathway enzymes. We demonstrate that the metabolically active cells in cannabis form a "supercell," with extensive cytoplasmic bridges across the cell walls and a polar distribution of organelles adjacent to the apical surface where metabolites are secreted. The predicted metabolic role of the non-photosynthetic plastids is supported by unusual membrane arrays in the plastids and the localization of the start of the cannabinoid/terpene pathway in the stroma of the plastids. Abundant membrane contact sites connected plastid paracrystalline cores with the plastid envelope, plastid with endoplasmic reticulum (ER), and ER with plasma membrane. The final step of cannabinoid biosynthesis, catalyzed by tetrahydrocannabinolic acid synthase (THCAS), was localized in the cell-surface wall facing the extracellular storage cavity. We propose a new model of how the cannabis cells can support abundant metabolite production, with emphasis on the key role of membrane contact sites and extracellular THCA biosynthesis. This new model can inform synthetic biology approaches for cannabinoid production in yeast or cell cultures. • Glandular cells form a polarized syncytium during THCA production and secretion • GPPS is located in plastids that contain conspicuous membrane fusions • THCAS is located exclusively on the extracellular surface of trichomes • Membrane contacts among plastids, ER, and PM inform a new trafficking model Cannabinoids and terpenes are biosynthesized, secreted, and stored in cannabis glandular trichomes. Livingston et al. reveal the nanoscale distribution of the enzymes involved in cannabinoid biosynthesis and the unique cellular environment where these enzymes operate. A new model of metabolite trafficking from the plastid to the cell wall is proposed. [ABSTRACT FROM AUTHOR]

Plants display an immense diversity of specialized metabolites, many of which have been important to humanity as medicines, flavors, fragrances, pigments, insecticides and other fine chemicals. Apparently, much of the variation in plant specialized metabolism evolved through events of gene duplications followed by neo- or sub-functionalization. Most of the catalytic diversity of plant enzymes is unexplored since previous biochemical and genomics efforts have focused on a relatively small number of species. Interdisciplinary research in plant genomics, microbial engineering and synthetic biology provides an opportunity to accelerate the discovery of new enzymes. The massive identification, characterization and cataloguing of plant enzymes coupled with their deployment in metabolically optimized microbes provide a high-throughput functional genomics tool and a novel strain engineering pipeline. [Copyright &y& Elsevier]

Summary: Tropane alkaloids are valuable pharmaceutical drugs derived from solanaceous plants such as Hyoscyamus niger (black henbane). The biosynthesis of these molecules, including the nature of the enigmatic rearrangement of (R)-littorine to (S)-hyoscyamine, is not completely understood. To test the hypothesis that a cytochrome P450 enzyme is involved in this rearrangement, we used virus-induced gene silencing to silence a cytochrome P450, CYP80F1, identified from H. niger roots by EST sequencing. Silencing CYP80F1 resulted in reduced hyoscyamine levels and the accumulation of littorine. Hyoscyamine was observed in CYP80F1-expressing tobacco hairy roots supplied with (R)-littorine. Expression in yeast confirmed that CYP80F1 catalyzes the oxidation of (R)-littorine with rearrangement to form hyoscyamine aldehyde, a putative precursor to hyoscyamine, and without rearrangement to form 3′-hydroxylittorine. Our data strongly support the involvement of CYP80F1 in the rearrangement of littorine to hyoscyamine. [Copyright &y& Elsevier]

With the medical use of cannabis permitted in Canada since 2001, patients seek to use this botanical drug to treat a range of medical conditions. However, many healthcare practitioners express the need for further scientific evidence around the use of medical cannabis. This real-world evidence study aimed to address the paucity of scientific data by surveying newly registered medical cannabis patients, before beginning medical cannabis treatment, and at one follow up 6 weeks after beginning medical cannabis treatment. The goal was to collect data on efficacy, safety and cannabis product type information to capture the potential impact medical cannabis had on patient-reported quality of life (QOL) and several medical conditions over a 6-week period using validated questionnaires. The 214 participants were mainly male (58%) and 57% of the population was older than 50. The most frequently reported medical conditions were recurrent pain, post-traumatic stress disorder (PTSD), anxiety, sleep disorders [including restless leg syndrome (RLS)], and arthritis and other rheumatic disorders. Here we report that over 60% of our medical cannabis cohort self-reported improvements in their medical conditions. With the use of validated surveys, we found significant improvements in recurrent pain, PTSD, and sleep disorders after 6 weeks of medical cannabis treatment. Our findings from patients who reported arthritis and other rheumatic disorders are complex, showing improvements in pain and global activity sub-scores, but not overall changes in validated survey scores. We also report that patients who stated anxiety as their main medical condition did not experience significant changes in their anxiety after 6 weeks of cannabis treatment, though there were QOL improvements. While these results show that patients find cannabis treatment effective for a broad range of medical conditions, cannabis was not a remedy for all the conditions investigated. Thus, there is a need for future clinical research to support the findings we have reported. Additionally, while real-world evidence has not historically been utilized by regulatory bodies, we suggest changes in public policy surrounding cannabis should occur to reflect patient reported efficacy of cannabis from real-world studies due to the uniqueness of medical cannabis's path to legalization., Competing Interests: All authors work for Aurora Cannabis Inc.® which is a for-profit company licensed for the cultivation and sale of medical cannabis., (Copyright © 2021 Cahill, Lunn, Diaz and Page.)

Cannabis ( Cannabis sativa ) resin is the foundation of a multibillion dollar medicinal and recreational plant bioproducts industry. Major components of the cannabis resin are the cannabinoids and terpenes. Variations of cannabis terpene profiles contribute much to the different flavor and fragrance phenotypes that affect consumer preferences. A major problem in the cannabis industry is the lack of proper metabolic characterization of many of the existing cultivars, combined with sometimes incorrect cultivar labeling. We characterized foliar terpene profiles of plants grown from 32 seed sources and found large variation both within and between sets of plants labeled as the same cultivar. We selected five plants representing different cultivars with contrasting terpene profiles for clonal propagation, floral metabolite profiling, and trichome-specific transcriptome sequencing. Sequence analysis of these five cultivars and the reference genome of cv Purple Kush revealed a total of 33 different cannabis terpene synthase ( CsTPS ) genes, as well as variations of the CsTPS gene family and differential expression of terpenoid and cannabinoid pathway genes between cultivars. Our annotation of the cv Purple Kush reference genome identified 19 complete CsTPS gene models, and tandem arrays of isoprenoid and cannabinoid biosynthetic genes. An updated phylogeny of the CsTPS gene family showed three cannabis-specific clades, including a clade of sesquiterpene synthases within the TPS-b subfamily that typically contains mostly monoterpene synthases. The CsTPSs described and functionally characterized here include 13 that had not been previously characterized and that collectively explain a diverse range of cannabis terpenes., (© 2020 American Society of Plant Biologists. All Rights Reserved.)

Cannabis sativa is widely cultivated for medicinal, food, industrial, and recreational use, but much remains unknown regarding its genetics, including the molecular determinants of cannabinoid content. Here, we describe a combined physical and genetic map derived from a cross between the drug-type strain Purple Kush and the hemp variety "Finola." The map reveals that cannabinoid biosynthesis genes are generally unlinked but that aromatic prenyltransferase ( AP ), which produces the substrate for THCA and CBDA synthases (THCAS and CBDAS), is tightly linked to a known marker for total cannabinoid content. We further identify the gene encoding CBCA synthase ( CBCAS ) and characterize its catalytic activity, providing insight into how cannabinoid diversity arises in cannabis. THCAS and CBDAS (which determine the drug vs. hemp chemotype) are contained within large (>250 kb) retrotransposon-rich regions that are highly nonhomologous between drug- and hemp-type alleles and are furthermore embedded within ∼40 Mb of minimally recombining repetitive DNA. The chromosome structures are similar to those in grains such as wheat, with recombination focused in gene-rich, repeat-depleted regions near chromosome ends. The physical and genetic map should facilitate further dissection of genetic and molecular mechanisms in this commercially and medically important plant., (© 2019 Laverty et al.; Published by Cold Spring Harbor Laboratory Press.)

Polyketides are an important group of secondary metabolites, many of which have important industrial applications in the food and pharmaceutical industries. Polyketides are synthesized from one of three classes of enzymes differentiated by their biochemical features and product structure: type I, type II or type III polyketide synthases (PKSs). Plant type III PKS enzymes, which will be the main focus of this review, are relatively small homodimeric proteins that catalyze iterative decarboxylative condensations of malonyl units with a CoA-linked starter molecule. This review will describe the plant type III polyketide synthetic pathway, including the synthesis of chalcones, stilbenes and curcuminoids, as well as recent work on the synthesis of these polyketides in heterologous organisms. The limitations and bottlenecks of heterologous expression as well as attempts at creating diversity through the synthesis of novel "unnatural" polyketides using type III PKSs will also be discussed. Although synthetic production of plant polyketides is still in its infancy, their potential as useful bioactive compounds makes them an extremely interesting area of study.

Purpose of Review: At the turn of the last century, rickets (vitamin D deficiency) was one of the most common musculoskeletal diseases of the paediatric population presenting to physicians. Today, the most common referral pathway for these patients ends in a paediatric orthopaedic outpatient clinic. Vitamin D deficiency is a clinical entity that can affect all children and should be looked for in all children with musculoskeletal symptoms., Recent Findings: The child at risk of rickets is now white, breastfed, protected from the sun and obese. Vitamin D deficiency can present as atypical muscular pain, pathological fractures or slipped upper femoral epiphysis. Obesity is linked with lower vitamin D levels; however, in the paediatric population, this does not necessarily equal clinical disorder. Vitamin D supplements can be used to reduce the risk of pathological fractures in the cerebral palsy child. It should also form part of the differential diagnosis in the work-up of nonaccidental injuries. Children with a low vitamin D present with a higher incidence of fractures from normal activities. Vitamin D levels need to be assessed before any form of orthopaedic surgery, as it can affect growth, both in the diaphysis of the bone and in the growth plate., Summary: Vitamin D levels are a key element in the successful practice of paediatric orthopaedics. It is not just the possible cause of disorder presenting to the clinician but also extremely important in ensuring the successful postoperative recovery of the patient.

Background: Cannabis sativa has been cultivated throughout human history as a source of fiber, oil and food, and for its medicinal and intoxicating properties. Selective breeding has produced cannabis plants for specific uses, including high-potency marijuana strains and hemp cultivars for fiber and seed production. The molecular biology underlying cannabinoid biosynthesis and other traits of interest is largely unexplored., Results: We sequenced genomic DNA and RNA from the marijuana strain Purple Kush using shortread approaches. We report a draft haploid genome sequence of 534 Mb and a transcriptome of 30,000 genes. Comparison of the transcriptome of Purple Kush with that of the hemp cultivar 'Finola' revealed that many genes encoding proteins involved in cannabinoid and precursor pathways are more highly expressed in Purple Kush than in 'Finola'. The exclusive occurrence of Δ9-tetrahydrocannabinolic acid synthase in the Purple Kush transcriptome, and its replacement by cannabidiolic acid synthase in 'Finola', may explain why the psychoactive cannabinoid Δ9-tetrahydrocannabinol (THC) is produced in marijuana but not in hemp. Resequencing the hemp cultivars 'Finola' and 'USO-31' showed little difference in gene copy numbers of cannabinoid pathway enzymes. However, single nucleotide variant analysis uncovered a relatively high level of variation among four cannabis types, and supported a separation of marijuana and hemp., Conclusions: The availability of the Cannabis sativa genome enables the study of a multifunctional plant that occupies a unique role in human culture. Its availability will aid the development of therapeutic marijuana strains with tailored cannabinoid profiles and provide a basis for the breeding of hemp with improved agronomic characteristics.

Virus-induced gene silencing (VIGS) exploits endogenous plant antiviral defense mechanisms to posttranscriptionally silence the expression of targeted plant genes. VIGS is quick and relatively easy to perform and therefore serves as a powerful tool for high-throughput functional genomics in plants. Combined with the use of subtractive cDNA libraries for generating a collection of VIGS-ready cDNA inserts, VIGS can be utilized to screen a large number of genes to determine phenotypes resulting from the knockdown/knockout of gene function. Taking into account the optimal insert design for VIGS, we describe a methodology for producing VIGS-ready cDNA libraries enriched for inserts relevant to the biological process of interest.

Background: Virus-induced gene silencing (VIGS) has emerged as a method for performing rapid loss-of-function experiments in plants. Despite its expanding use, the effect of host gene insert length and other properties on silencing efficiency have not been systematically tested. In this study, we probed the optimal properties of cDNA fragments of the phytoene desaturase (PDS) gene for efficient VIGS in Nicotiana benthamiana using tobacco rattle virus (TRV)., Results: NbPDS inserts of between 192 bp and 1304 bp led to efficient silencing as determined by analysis of leaf chlorophyll a levels. The region of the NbPDS cDNA used for silencing had a small effect on silencing efficiency with 5' and 3' located inserts performing more poorly than those from the middle. Silencing efficiency was reduced by the inclusion of a 24 bp poly(A) or poly(G) homopolymeric region. We developed a method for constructing cDNA libraries for use as a source of VIGS-ready constructs. Library construction involved the synthesis of cDNA on a solid phase support, digestion with RsaI to yield short cDNA fragments lacking poly(A) tails and suppression subtractive hybridization to enrich for differentially expressed transcripts. We constructed two cDNA libraries from methyl-jasmonate treated N. benthamiana roots and obtained 2948 ESTs. Thirty percent of the cDNA inserts were 401-500 bp in length and 99.5% lacked poly(A) tails. To test the efficiency of constructs derived from the VIGS-cDNA libraries, we silenced the nicotine biosynthetic enzyme, putrescine N-methyltransferase (PMT), with ten different VIGS-NbPMT constructs ranging from 122 bp to 517 bp. Leaf nicotine levels were reduced by more than 90% in all plants infected with the NbPMT constructs., Conclusion: Based on the silencing of NbPDS and NbPMT, we suggest the following design guidelines for constructs in TRV vectors: (1) Insert lengths should be in the range of ~200 bp to ~1300 bp, (2) they should be positioned in the middle of the cDNA and (3) homopolymeric regions (i.e. poly(A/T) tails) should not be included. Our VIGS-cDNA library method, which incorporates these guidelines to produce sequenced, VIGS-ready cDNAs, will be useful for both fast-forward and reverse genetics experiments in TRV vectors.

A cDNA encoding a stilbene synthase, RtSTS, was isolated from the rhizomes of Tatar rhubarb, Rheum tataricum L. (Polygonaceae), a medicinal plant containing stilbenes and other polyketides. Recombinant RtSTS was expressed in E. coli and assayed with acetyl-coenzyme A (CoA), n-butyryl-CoA, isovaleryl-CoA, n-hexanoyl-CoA, cinnamoyl-CoA and p-coumaroyl-CoA as primers of polyketide synthesis. RtSTS synthesized resveratrol and a trace amount of naringenin chalcone from p-coumaroyl-CoA, supporting the enzyme's identification as a resveratrol-type stilbene synthase (EC 2.3.1.95). Bis-noryangonin and p-coumaroyl triacetic acid lactone (CTAL)-type pyrones were observed in minor amounts in the reaction with p-coumaroyl-CoA and as major products with cinnamoyl CoA. As well, such pyrones, and not aromatic polyketides, were identified as the only products in assays with aliphatic and benzoyl CoA esters. Acetonyl-4-hydroxy-2-pyrone, a pyrone synthesized from acetyl-CoA, was identified as a new product of a stilbene synthase. Using Northern blot analysis, RtSTS transcript was found to be highly expressed in R. tataricum rhizomes, with low transcript levels also present in young leaves. This expression pattern correlated with the occurrence of resveratrol, which was detected in higher amounts in R. tataricum rhizomes compared with leaves and petioles using HPLC. Few stilbene synthases have been found in plants, and the identification of RtSTS provides additional sequence and catalytic information with which to study the evolution of plant polyketide synthases.

The phytochelatin homologs homo-phytochelatins are heavy metal-binding peptides present in many legumes. To study the biosynthesis of these compounds, we have isolated and functionally expressed a cDNA GmhPCS1 encoding homo-phytochelatin synthase from Glycine max, a plant known to accumulate homo-phytochelatins rather than phytochelatins upon the exposure to heavy metals. The catalytic properties of GmhPCS1 were compared with the phytochelatin synthase AtPCS1 from Arabidopsis thaliana. When assayed only in the presence of glutathione, both enzymes catalyzed phytochelatin formation. GmhPCS1 accepted homoglutathione as the sole substrate for the synthesis of homo-phytochelatins whereas AtPCS1 did not. Homo-phytochelatin synthesis activity of both recombinant enzymes was significantly higher when glutathione was included in the reaction mixture. The incorporation of both glutathione and homoglutathione into homo-phytochelatin, n = 2, was demonstrated using GmhPCS1 and AtPCS1. In addition to bis(glutathionato)-metal complexes, various other metal-thiolates were shown to contribute to the activation of phytochelatin synthase. These complexes were not accepted as substrates by the enzyme, thereby suggesting that a recently proposed model of activation cannot fully explain the catalytic mechanism of phytochelatin synthase (Vatamaniuk, O. K., Mari, S., Lu, Y. P., and Rea, P. A. (2000) J. Biol. Chem. 275, 31451-31459).