The Diesel Tree Sindora glabra Genome Provides Insights Into the Evolution of Oleoresin Biosynthesis

Sindora glabra is an economically important tree that produces abundant oleoresin in the trunk. Here, we present a high-quality chromosome-scale assembly of S. glabra genome by combining Illumina HiSeq, Pacific Biosciences sequencing, and Hi-C technologies. The size of S. glabra genome was 1.11 Gb, with a contig N50 of 1.27 Mb and 31,944 predicted genes. This is the first sequenced genome of the subfamily Caesalpinioideae. As a sister taxon to Papilionoideae, S. glabra underwent an ancient genome triplication shared by core eudicots and further whole-genome duplication shared by early-legume in the last 73.3 million years. S. glabra harbors specific genes and expanded genes largely involved in stress responses and biosynthesis of secondary metabolites. Moreover, 59 terpene backbone biosynthesis genes and 64 terpene synthase genes were identified, which together with co-expressed transcription factors could contribute to the diversity and specificity of terpene compounds and high terpene content in S. glabra stem. In addition, 63 disease resistance NBS-LRR genes were found to be unique in S. glabra genome and their expression levels were correlated with the accumulation of terpene profiles, suggesting potential defense function of terpenes in S. glabra. These together provide new resources for understanding genome evolution and oleoresin production.

Effect of Fire Frequency on the Flammability of Two Mediterranean Pines: Link with Needle Terpene Content

Flammability is a major factor involved in Mediterranean plant evolution that has led to the diversity of fire-related traits according to fire regimes and fire-adaptive strategies. With on-going climate change, new fire regimes are threatening plant species if they do not adapt or acclimate. Studying flammability and terpene content variation according to the different fire frequencies in the recent fire history represents a great challenge to anticipating the flammability of ecosystems in the near future. The flammability of shoots and litter as well as the needle terpene contents of two pine species with different fire adaptive strategies (Pinus halepensis and Pinus sylvestris) were measured according to two fire modalities (0 vs. 1–2 fire events over the last 60 years). Results showed that, regardless of the species and the fuel type, flammability was higher in populations having undergone at least one past fire event even when factors influencing flammability (e.g., structural traits and hydric content) were considered. The terpene content did not vary in P. sylvestris’ needles according to the fire modality, but that of sesqui- and diterpenes was higher in P. halepensis’ needles sampled in the “Fire” modality. In addition, associations made between flammability and terpene content using random forest analyses indicated that the terpene molecules differed between fire modalities for both species and fuel types. The same results were obtained with significant terpenes driving flammability as were highlighted in the PLS analyses, especially for P. halepensis for which enhanced shoot flammability in the “Fire” modality agreed with the adaptive strategy of this species to fire.

The Phytochemical Diversity of Commercial Cannabis in the United States

The legal status of Cannabis is changing, fueling an increased diversity of Cannabis-derived products. Because Cannabis contains dozens of chemical compounds with potential psychoactive or medicinal effects, understanding its phytochemical diversity is crucial. The legal Cannabis industry heavily markets products to consumers based on widely used labelling systems purported to predict the effects of different Cannabis "strains." We analyzed the cannabinoid and terpene content of tens of thousands of commercial Cannabis samples across six US states, finding distinct chemical phenotypes (chemotypes) which are reliably present. After careful descriptive analysis of the phytochemical diversity and comparison to the commercial labels commonly attached to Cannabis samples, we show that commercial labels do not consistently align with the observed chemical diversity. However, certain labels are statistically overrepresented for specific chemotypes. These results have important implications for the classification of commercial Cannabis, the design of animal and human research, and the regulation of legal Cannabis marketing.

Does Seasonality of Leaf Terpene Content and Moisture Content Trigger Leaf Flammability Seasonal Variation?

Given the importance of terpenes and fuel moisture content (FMC) on flammability, this work aims at checking how these parameters affect leaf flammability of different native and Wildland-Urban Interfaces species (Pinus halepensis, Cupressus sempervirens, Cupressocyparis leylandii, and Hesperocyparis arizonica) across seasons in the French Mediterranean region. We found that the highest terpene diversity and content seasonally varied according to the species, with diterpene content being lower in spring for C. leylandii, while monoterpene and diterpene content being higher in summer and winter, respectively, for P. halepensis. Flammability and FMC varied according to the season but the pattern differed among species. A significant correlation between the latters was rarely observed and occurred in only one season, differing among species. The correlations between flammability and terpenes were mostly highlighted using single compounds, compared to subgroups, and they presented seasonal patterns varying among species. Checking the seasonal effect of groups of terpene compounds on flammability, there were seasonal differences in these groups according to the species and the variable tested. Mostly, these significant compounds were not the most concentrated. The best flammability drivers of each model, mostly diterpenes, except for P. halepensis whose flammability was mostly drove by mono- and sesquiterpenes, changed among seasons according to the flammability variable considered. When a best driver remained the same in different seasons, its effect on flammability could be opposite. In contrast, FMC was generally not a significant explanatory parameter of leaf flammability or did not improve the fit of models.

The influence of terpenes on the release of volatile organic compounds and active ingredients to cannabis vaping aerosols

Cannabinoid and VOC emissions from vaping cannabis concentrates vary depending on terpene content, power level and consumption method.

Evolution of the Polyphenol and Terpene Content, Antioxidant Activity and Plant Morphology of Eight Different Fiber-Type Cultivars of Cannabis sativa L. Cultivated at Three Sowing Densities

The chemical composition of the inflorescences of eight different fibre-type Cannabis sativa L. cultivars grown in Switzerland was monitored for different sowing densities over the season 2019. HPLC-MS, GC-MS and GC-FID, as well as spectrophotometric techniques were used to measure the total phenolic content (TPC) and the antioxidative activity of the inflorescence extracts, and to characterise and quantify the flavonoids and terpenes produced by the different cultivars over different sowing densities from July to September 2019. The main finding of the present study is that the TPC, as well as the individual flavonoids and terpenes, were mainly influenced by the harvest period and the phenological stage of the plant. The content of polyphenols and flavonoids decrease during the flower development for all cultivars studied. The terpene content increased with maturation. The monoterpenes/sesquiterpenes ratio also changed between the early flowering (majority of sesquiterpenes) and the end of flowering (majority of monoterpenes). The sowing density showed an impact on plant morphology, a low density such as 30 seeds/m2 influencing the production of bigger flowers, thus increasing the yield of polyphenols and terpenes production. Therefore, hemp inflorescences can be regarded as valuable by-products of fibre production, for their valorisation in the food and beverage industry in addition to cosmetics and perfumery.

Predicting terpene content in dried conifer shoots using near infrared spectroscopy

Terpenes are phytochemicals found in multiple plant genera, especially aromatic herbs and conifers. Terpene content quantification is costly and complex, requiring the extraction of oil content and gas chromatography analyses. Near infrared (NIR) spectroscopy could provide an alternative quantitative method, especially if calibration can be developed with the spectra of dried plant material, which are easier and faster to acquire than oil-based spectra. Here, multispecies NIR spectroscopy calibrations were developed for total terpene content (mono- and sesquiterpenes) and for specific terpenes (α-pinene, β-pinene and myrcene) with five conifers species ( Picea glauca, Picea rubens, Pinus resinosa, Pinus strobus and Thuja occidentalis). The terpene content of fresh shoot samples was quantified with gas chromatography. The NIR spectra were measured on freeze-dried samples (n = 137). Using a subset of the samples, modified partial least squares regressions of total terpene and the three individual terpenes content were generated as a functions of the NIR spectra. The standard errors of the internal cross-validations (values between 0.25 and 2.28) and the ratio of prediction to deviation ratios (RPD values between 2.20 and 2.38) indicate that all calibrations have similar accuracy. The independent validations, however, suggest that the calibrations for total terpene and α-pinene content are more accurate (respective coefficient of determination: r2 = 0.85 and 0.82). In contrast, calibrations for β-pinene and myrcene had a low accuracy (respectively: r2 = 0.62 and 0.08), potentially because of the low concentration of these terpenes in the species studied. The calibration model fits (i.e., r2) are comparable to previously published calibration using the spectra of dried shoot samples and demonstrate the potential of this method for terpenes in conifer samples. The calibration method used could be useful in several other domains (e.g. seedling breeding program, industrial), because of the wide distribution of terpenes and especially of pinenes.

The preservation and augmentation of volatile terpenes in cannabis inflorescence

Background Terpenes contribute to the pharmacology, efficacy, aroma, and flavor of cannabis inflorescence, improving the experience for medical and recreational users. Terpenes are inherently volatile, resulting in the loss of terpene content as inflorescence ages. A method to establish and/or maintain a desired terpene content of cannabis inflorescence is needed. A novel packaging method was investigated for the preservation of native terpenes and the replenishment of terpenes to depleted inflorescence over various storage durations. Methods Inflorescence samples from two different chemotypes (DJ’s Gold, Cream Caramel) were obtained from a state licensed medical cannabis organization. Samples from the DJ’s Gold chemotype were depleted of terpenes whereas samples from the Cream Caramel chemotype had a terpene content representative of inflorescence available for medicinal or recreational purposes. Inflorescence samples were stored using the novel packaging approach, in airtight containers in the presence of external terpenes. Control samples were similarly stored without external terpenes. Terpene content of the inflorescence samples were quantitively determined by headspace gas chromatography mass spectrometry (HS GC-MS) after various storage durations. Main effects analysis was used to determine the impact of various parameters on the effectiveness of the system. Results All samples stored using the novel packaging approach had a higher terpene content than their corresponding control. 1.18% (w/w) of external terpene, relative to inflorescence weight, was the minimum amount required to maintain the initial terpene content of the inflorescence after 6 weeks of storage. Main effects analysis showed that augmentation of inflorescence terpene content was dependent upon the amount and type of external volatile utilized. The terpene profile of inflorescence samples from two separate harvests were selectively adjusted, reducing the percent difference of the two sample’s terpene profiles by 39.5%. Conclusions A successful proof of concept was achieved for preservation, augmentation, and replenishment of terpenes to cannabis inflorescence over various storage durations. Inflorescence stored using the novel packaging approach is a significant step towards providing patients with cannabis inflorescence of reproducible and reliable terpene content, an important component of inflorescence efficacy. The novel approach for replenishment of terpenes to depleted inflorescence represents an exciting development for patients and manufacturers.

Pine Species That Support Crown Fire Regimes Have Lower Leaf-Level Terpene Contents Than Those Native to Surface Fire Regimes

Fire is increasingly being recognised as an important evolutionary driver in fire-prone environments. Biochemical traits such as terpene (volatile isoprenoid) concentration are assumed to influence plant flammability but have often been overlooked as fire adaptations. We have measured the leaf-level flammability and terpene content of a selection of Pinus species native to environments with differing fire regimes (crown fire, surface fire and no fire). We demonstrate that this biochemical trait is associated with leaf-level flammability which likely links to fire-proneness and we suggest that this contributes to post-fire seedling survival. We find that surface-fire species have the highest terpene abundance and are intrinsically the most flammable, compared to crown-fire species. We suggest that the biochemical traits of surface fire species may have been under selective pressure to modify the fire environment at the leaf and litter scale to moderate fire spread and intensity. We indicate that litter flammability is driven not only by packing ratios and bulk density, but also by terpene content.