DNA methylation: a historical perspective.

Legal Cannabis production is now experiencing growing consumer demand due to changing legislation around the world. However, because of heavy restrictions on cannabis cultivation over the past century, little scientific research has been conducted on this crop, in particular around use of members of the phytomicrobiome to improve crop yields. Recent developments in the field of plant science have demonstrated that application of microbes, isolated from the rhizosphere, have enormous potential to improve yields, in particular under stressful growing conditions. This perspective carefully examines the potential for plant growth-promoting rhizobacteria (PGPR) to improve marijuana and hemp yield and quality. It then explores the potential use of PGPR for biological control of plant pathogens, which is particularly interesting given the stringent regulation of pesticide residues on this crop. As an industry-relevant example, biocontrol of powdery mildew, a common and deleterious pathogen affecting cannabis production, is assessed. Finally, two PGPR in genera frequently associated with higher plants (Pseudomonas and Bacillus) were selected as case studies for the potential effects on growth promotion and disease biocontrol in commercial cannabis production.

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Plant Growth-Promoting Rhizobacteria for Cannabis Production: Yield, Cannabinoid Profile and Disease Resistance

Cannabis is a diverse and polymorphic species. To better understand cannabinoid synthesis inheritance and its impact on pathogen resistance, we shotgun sequenced and assembled a Cannabis trio (sibling pair and their offspring) utilizing long read single molecule sequencing. This resulted in the most contiguous Cannabis sativa assemblies to date. These reference assemblies were further annotated with full-length male and female mRNA sequencing (Iso-Seq) to help inform isoform complexity, gene model predictions and identification of the Y chromosome. To further annotate the genetic diversity in the species, 40 male, female, and monoecious cannabis and hemp varietals were evaluated for copy number variation (CNV) and RNA expression. This identified multiple CNVs governing cannabinoid expression and 82 genes associated with resistance to Golovinomyces chicoracearum, the causal agent of powdery mildew in cannabis. Results indicated that breeding for plants with low tetrahydrocannabinolic acid (THCA) concentrations may result in deletion of pathogen resistance genes. Low THCA cultivars also have a polymorphism every 51 bases while dispensary grade high THCA cannabis exhibited a variant every 73 bases. A refined genetic map of the variation in cannabis can guide more stable and directed breeding efforts for desired chemotypes and pathogen-resistant cultivars.

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Sequence and annotation of 42 cannabis genomes reveals extensive copy number variation in cannabinoid synthesis and pathogen resistance genes

DNA methylation (DNAme) and histone post-translational modifications (PTMs) have important roles in transcriptional regulation. Although many reports have characterized the functions of such chromatin marks in isolation, recent genome-wide studies reveal surprisingly complex interactions between them. Here, we focus on the interplay between DNAme and methylation of specific lysine residues on the histone H3 tail. We describe the impact of genetic perturbation of the relevant methyltransferases in the mouse on the landscape of chromatin marks as well as the transcriptome. In addition, we discuss the specific neurodevelopmental growth syndromes and cancers resulting from pathogenic mutations in the human orthologues of these genes. Integrating these observations underscores the fundamental importance of crosstalk between DNA and histone H3 methylation in development and disease. In this Review, Janssen and Lorincz discuss the intricate and multilayered interplay between chromatin marks. Focusing on histone methylation and DNA methylation during mammalian development, they discuss the implications for gene regulation, differentiation and human disease.

Interplay between chromatin marks in development and disease.

BAP1 enhances Polycomb repression by counteracting widespread H2AK119ub1 deposition and chromatin condensation.

Until recently, the commercial production of Cannabis sativa was restricted to varieties that yielded high-quality fiber while producing low levels of the psychoactive cannabinoid tetrahydrocannabinol (THC). In the last few years, a number of jurisdictions have legalized the production of medical and/or recreational cannabis with higher levels of THC, and other jurisdictions seem poised to follow suit. Consequently, demand for industrial-scale production of high yield cannabis with consistent cannabinoid profiles is expected to increase. In this paper we highlight that currently, projected annual production of cannabis is based largely on facility size, not yield per square meter. This meta-analysis of cannabis yields reported in scientific literature aimed to identify the main factors contributing to cannabis yield per plant, per square meter, and per W of lighting electricity. In line with previous research we found that variety, plant density, light intensity and fertilization influence cannabis yield and cannabinoid content; we also identified pot size, light type and duration of the flowering period as predictors of yield and THC accumulation. We provide insight into the critical role of light intensity, quality, and photoperiod in determining cannabis yields, with particular focus on the potential for light-emitting diodes (LEDs) to improve growth and reduce energy requirements. We propose that the vast amount of genomics data currently available for cannabis can be used to better understand the effect of genotype on yield. Finally, we describe diversification that is likely to emerge in cannabis growing systems and examine the potential role of plant-growth promoting rhizobacteria (PGPR) for growth promotion, regulation of cannabinoid biosynthesis, and biocontrol.

/pdf/closing-the-yield-gap-for-cannabis-a-meta-analysis-of-5ghooyd9ef.pdf

Closing the Yield Gap for Cannabis: A Meta-Analysis of Factors Determining Cannabis Yield

Precise deposition of CpG methylation is critical for mammalian development and tissue homeostasis and is often dysregulated in human diseases. The localization of de novo DNA methyltransferase DNMT3A is facilitated by its PWWP domain recognizing histone H3 lysine 36 (H3K36) methylation1,2 and is normally depleted at CpG islands (CGIs)3. However, methylation of CGIs regulated by Polycomb repressive complexes (PRCs) has also been observed4-8. Here, we report that DNMT3A PWWP domain mutations identified in paragangliomas9 and microcephalic dwarfism10 promote aberrant localization of DNMT3A to CGIs in a PRC1-dependent manner. DNMT3A PWWP mutants accumulate at regions containing PRC1-mediated formation of monoubiquitylated histone H2A lysine 119 (H2AK119ub), irrespective of the amounts of PRC2-catalyzed formation of trimethylated histone H3 lysine 27 (H3K27me3). DNMT3A interacts with H2AK119ub-modified nucleosomes through a putative amino-terminal ubiquitin-dependent recruitment region, providing an alternative form of DNMT3A genomic targeting that is augmented by the loss of PWWP reader function. Ablation of PRC1 abrogates localization of DNMT3A PWWP mutants to CGIs and prevents aberrant DNA hypermethylation. Our study implies that a balance between DNMT3A recruitment by distinct reader domains guides de novo CpG methylation and may underlie the abnormal DNA methylation landscapes observed in select human cancer subtypes and developmental disorders.

Two competing mechanisms of DNMT3A recruitment regulate the dynamics of de novo DNA methylation at PRC1-targeted CpG islands.

<h3>Objective:</h3> To perform a retrospective cohort study describing Cannabidiol (CBD) use in a concussion clinic. <h3>Background:</h3> People report using CBD for a range of symptoms, many of which overlap with post-concussion symptoms. CBD use has not been assessed in a concussed population. We performed a retrospective cohort study to describe CBD use in a concussion clinic. We hypothesized CBD use would be more likely in patients with psychiatric diagnoses, headaches, cannabis use, and greater post-concussion symptoms and concussion chronicity. We assessed whether cannabis use could account for any of the findings. <h3>Design/Methods:</h3> We reviewed medical notes from 567 selected patients aged &gt;=18 from 07/26/2018 to 07/27/2021 and extracted self-reported CBD use and demographics, medical history, and post-concussion symptoms (via Graded Symptom Checklist (GSC)). We used descriptive and non-parametric statistics to test our hypotheses. <h3>Results:</h3> CBD users made up 11% of the cohort and did not differ on demographic variables (e.g., age, sex, injury acuity) from non-users. After adjusting for age, sex, injury acuity, and cannabis use, CBD users had a 3.48 (1.80, 6.75) (<i>p</i> &lt; 0.001) and 1.99 (1.04, 3.99) (<i>p</i> = 0.04) times higher odds of reporting cannabis use and a psychiatric diagnosis, respectively, but no difference in headaches (<i>p</i> = 0.61). CBD users relative to non-users reported greater total post-concussion symptoms (CBD users GSC = 58.59, Non-users GSC = 45.73, <i>p</i> = 0.04), which was driven by cognitive (<i>p</i>=0.03) and physical (<i>p</i>=0.05) symptoms. Despite the correlation between cannabis and CBD use, cannabis use did not correlate with greater post-concussion symptoms. <h3>Conclusions:</h3> This study is the first to describe CBD use in concussed patients. CBD use was more common in concussed patients with premorbid psychiatric diagnoses and greater post-concussive symptoms, and this was not influenced by cannabis use. Prospective studies are necessary to assess the safety and efficacy of CBD in concussion. <b>Disclosure:</b> Dr. Rafie has nothing to disclose. Mr. Rosenbaum has received research support from Region IV Training Center. Dr. Bickart has nothing to disclose. Neil Avinash Bhathela, MD has nothing to disclose. Mr. Chung has nothing to disclose. Dr. Giza has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Highmark Interactive. Dr. Giza has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis Pharmaceutical. Dr. Giza has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Lewitt, Hackman, Shapiro, Marshall &amp; Harlan. Dr. Giza has received stock or an ownership interest from Highmark Interactive. The institution of Dr. Giza has received research support from NCAA. The institution of Dr. Giza has received research support from US Department of Defense. The institution of Dr. Giza has received research support from UCLA: Brain Injury Research Center, Steve Tisch BrainSPORT Program, Easton Clinic for Brain Health. Dr. Giza has received publishing royalties from a publication relating to health care. Dr. Choe has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Legal Cases. The institution of Dr. Choe has received research support from NIH. The institution of Dr. Choe has received research support from AIR-P. Dr. Choe has a non-compensated relationship as a Board of Directors with NABIS that is relevant to AAN interests or activities. Dr. Choe has a non-compensated relationship as a Consultant with USA Swimming Concussion Task Force that is relevant to AAN interests or activities. 

Phillip Rosenbaum

Papers

Closing the Yield Gap for Cannabis: A Meta-Analysis of Factors Determining Cannabis Yield

Two competing mechanisms of DNMT3A recruitment regulate the dynamics of de novo DNA methylation at PRC1-targeted CpG islands.

A Retrospective Analysis of Cannabidiol (CBD) Use in a Concussion Cohort (P7-1.007)