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Cannabis is a dioecious species. A female individual (left) and a male individual (right) of a dioecious hemp cultivar. Photo on the right by Jiaqi Shi.
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Cannabis sativa is well known for its production of psychoactive chemicals and medicinal products, but it also has huge potential to be a multipurpose crop. Cultivated for biofuel, building materials and textiles, Cannabis has a high carbon sequestration rate and is bound to be a key player in future sustainable agriculture. The distinct applicatio...
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... important aspect of Cannabis biology is that the species is dioecious (a Greek word that translates to 'two households') meaning that separate male and female individuals exist (see Figure 4). Most flowering plants have bisexual flowers with male and female reproductive organs together in one flower, and dioecy like in Cannabis is found in only ~6% of flowering plant species. ...
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... Finally, hemp contributes to the provision of the ecosystem's services by supporting pollination. Late-season crop flowering provides bee communities with supplementary nutritional resources during the months of floral scarcity (i.e., late summer and the beginning of autumn in Italy) (Dowling et al., 2021), thus sustaining pollination and biodiversity richness, with benefits for the other crops in the agroecosystems and the surrounding natural systems (Journals and Dalio, 2014;Flicker et al., 2020). ...
Introduction: Hemp is a crop cultivated in Europe since ancient times, with a variety of purposes and products. Despite being known for its positive environmental effects on ecosystems, the impacts of hemp-based food products have not been sufficiently investigated yet. This paper contributed to deepen the knowledge of the hemp industry by focusing on the potential environmental impact of the cultivation phase (under three different agronomic practices in Italy: organic outdoor and conventional outdoor, and indoor) and the production of selected hemp-based goods (seed oil and flour for food purposes and flowers for therapeutic uses).
Methods: The impact was quantified utilizing the life cycle assessment within different impact categories, such as carbon footprint (CF), eutrophication (EP), acidification (AP), and water footprint (WF). For a carbon offset assessment, the carbon storage capability (i.e., the carbon fixed in crop residues left in the field) of hemp was also investigated through the guidelines provided by the Intergovernmental Panel on Climate Change (IPCC).
Results and Discussion: The cultivation phase contributed to a CF that ranged from 1.2 (organic outdoor) to 374 (indoor) kg per kg of grains (conventional outdoor). These results were in line with the literature. Sensitivity scenarios based on hotspot analysis were also presented for CF mitigation for each kind of cultivation. On the other hand, the ability of hemp to sequester carbon in the soil due to crop residues left in the field (i.e., carbon storage) was evaluated (−2.7 kg CO2 (ha year)⁻¹), showing that the CF was fully compensated (−0.27 kg CO2 (ha year)⁻¹ for conventional outdoor and −1.07 kg CO2 (ha year)⁻¹ for organic outdoor). Regarding hemp-based products, only dried flowers showed a negative balance (−0.99 kg CO2 per kg dry flower), while hemp oil and flour reported 31.79 kg CO2 per kg flour) when carbon storage was accounted. The results support the idea that the production chain can be sustainable and carbon-neutral only when all the different parts of the plant (flowers, seeds, fibers, leaves, and all residues) were used to manufacture durable goods according to the framework of the circular economy.
... Cannabis sativa has long been known to have both therapeutic and psychoactive properties. It is a multipurpose plant that is used for recreational, medicinal, and industrial purposes [2]. Cannabis is currently the focus of a significant amount of research due to its unique phytochemical constituents, i.e., secondary metabolites. ...
Cannabis sativa is a medicinal plant that has been known for years and is used as an Ayurvedic medicine. This plant has great potential in treating various types of brain diseases. Phytochemicals present in this plant act as antioxidants by maintaining synaptic plasticity and preventing neuronal loss. Cannabidiol (CBD) and Tetrahydrocannabinol (THC) are both beneficial in treating Alzheimer’s disease by increasing the solubility of Aβ42 amyloid and Tau aggregation. Apart from these therapeutic effects, there are certain unknown functions of these phytochemicals in Alzheimer’s disease that we want to elucidate through this study. In this research, our approach is to analyze the effect of phytochemicals in Cannabis sativa on multiple culprit enzymes in Alzheimer’s disease, such as AChE (Acetylcholinesterase), BChE (Butyrylcholinesterase), γ-secretase, and BACE-1. In this study, the compounds were selected by Lipinski’s rule, ADMET, and ProTox based on toxicity. Molecular docking between the selected compounds (THCV, Cannabinol C2, and Cannabidiorcol) and enzymes mentioned above was obtained by various software programs including AutoDock Vina 4.2, AutoDock, and iGEMDOCK. In comparison to Donepezil (BA = −8.4 kcal/mol, Ki = 1.46 mM), Rivastigmine (BA = −7.0 kcal/mol, Ki = 0.02 mM), and Galantamine (BA = −7.1, Ki = 2.1 mM), Cannabidiorcol (BA = −9.4 kcal/mol, Ki = 4.61 mM) shows significant inhibition of AChE. On the other hand, Cannabinol C2 (BA = −9.2 kcal/mol, Ki = 4.32 mM) significantly inhibits Butyrylcholinesterase (BuChE) in comparison to Memantine (BA = −6.8 kcal/mol, Ki = 0.54 mM). This study sheds new light and opens new avenues for elucidating the role of bioactive compounds present in Cannabis sativa in treating Alzheimer’s disease.
... The flowering of most cannabis cultivars is dependent on the precise timing of day-light cycles, requiring 12 h of light and 12 h of dark to initiate flowering, which has further challenged outdoor growth in temperate climates. Some auto-flowering cultivars exist, in which the timing of flowering is not dependent on the light cycle under which the plants are grown (Dowling et al., 2021). Successful outdoor cultivation in temperate climates currently requires auto-flowering cultivars, limiting the varieties that are available for this type of production. ...
The growth, distribution, and use of Cannabis sativa (cannabis) have been tightly restricted for decades due to the therapeutic and psychoactive molecules it produces. Despite long-standing cultivation, scientific research on cannabis has been limited, with past efforts to breed and improve this crop largely supported by an illegal global economy. The easing of legal restrictions and the rapid growth of genomic tools and biotechnology have accelerated research and targeted trait development in cannabis. These advances have enabled the establishment of regulatory standards that ensure safe products for human consumption, and supported efforts to bioengineer cannabinoid production for an eco-conscious future. This chapter discusses societal and scientific influences on the cannabis plant, with a focus on the impact of genomics and biotechnology on cannabis research, and the legal and environmental challenges faced by the future of this industry and its impact on the global bioeconomy.
... Afin d'identifier le ou les gènes responsables du déterminisme du sexe, nous avons débuté une collaboration avec un groupe du University College of Dublin. Cette équipe de recherche, dirigée par Rainer Melzer, fait dorénavant partie des groupes spécialistes de la génétique du développement chez C. sativa Dowling, Melzer et Schilling, 2021). Leurs travaux portent principalement sur la génétique de la floraison et, depuis notre collaboration, sur le déterminisme génétique du sexe. ...
La trajectoire décrivant l’évolution d’une paire de chromosomes sexuels à longtemps été proposée comme étant universelle pour tous les systèmes, cependant des propositions alternatives ont récemment nuancé ce «modèle» unique. D’après ce modèle, il y aurait dans un premier temps l’émergence d’une région non-recombinante (XY ou ZW), puis, une expansion de celle-ci. Simultanément, l’absence de recombinaison induit ce que l’on appelle la dégénérescence du chromosome Y (ou W). La dégénérescence est supposée augmenter et, après un certain temps évolutif, devrait conduire à un système dans lequel le chromosome Y (ou W) serait plus petit que le chromosome X (ou Z), voire disparaît. Cependant, seulement une trentaine de paires de chromosomes sexuels de plantes ont été étudiées avec des données empiriques, parmi plus de 15 000 espèces dioïques (i.e. plantes à sexes séparés). Il en résulte que certaines étapes du systèmes sont mieux supportées que d’autres. Plus précisément, la formation de la région non-recombinante a essentiellement été étudiée de manière théorique, tandis qu’une forte dégénérescence avec un chromosome Y (ou W) plus petit que le chromosome X (ou Z) n’a été décrite que chez les animaux. Afin de mieux décrire la première étape du modèle, l’émergence de la région non recombinante, le premier axe de cette thèse représente une étude de Silene acaulis ssp exscapa, la seule sous-espèce dioïque du complexe Silene acaulis. En effet, ceci laisse supposer que ce système sexuel est un caractère dérivé, donc probablement récent. Le mécanisme du déterminisme du sexe n’étant pas connu, j’ai voulu savoir si une région non-recombinante typique d’une paire de chromosomes sexuels est présente chez cette sous-espèce. Pour cela, j’ai utilisé un outil récemment publié basé sur l’analyse de fréquences génotypiques et phénotypiques de mâles et de femelles au sein d’une population. Deux jeux de données RNA-seq provenant de deux populations différentes ont permis d’identifier 27 gènes potentiellement XY, et suggèrent que la paire de chromosomes sexuels serait récente. Des analyses complémentaires sont tout de même nécessaires pour confirmer ces résultats. Deuxièmement, afin de tester l’existence d’une paire ancienne de chromosomes sexuels avec une forte dégénérescence chez les plantes, le deuxième axe de cette thèse est une étude de deux espèces dioïques de la famille des Cannabaceae, Cannabis sativa et Humulus lupulus. En effet, l’ancêtre commun de ces deux espèces, qui divergent depuis plusieurs dizaines de millions d’années, était probablement dioïque. De plus, des analyses cytologiques ont identifié des paires de chromosomes sexuels qui pourraient être anciennes. Pour caractériser l’âge et le niveau de dégénérescence de ces paires de chromosomes sexuels, des données RNA-seq d’un croisement ont été générées pour chacune des deux espèces. Un outil probabiliste analysant les ségrégations alléliques au sein d’un croisement a permis d’identifier la première paire de chromosomes sexuels homologue entre deux genres chez les plantes. De plus, ces chromosomes sexuels sont parmi les plus vieux et les plus dégénérés actuellement décrits chez les plantes. Par ailleurs, la détection de séquence Y-spécifiques pourrait permettre d’améliorer la culture de ces deux espèces puisque seules les femelles ont un intérêt économique et que le dimorphisme sexuel est faible. J’ai développé des amorces PCR qui montrent des résultats prometteurs. Plus généralement, ces résultats apportent de nouvelles informations concernant les étapes les moins bien décrites de l’évolution des chromosomes sexuels chez les plantes. Premièrement, nous montrons qu’une paire de chromosomes sexuels a probablement émergé récemment dans une espèce, et confirmons l’intérêt de continuer à l’étudier. Deuxièmement, nous confirmons que des chromosomes sexuels vieux et fortement dégénérés existent chez les plantes.
Hemp ( Cannabis sativa L.) is an extraordinarily versatile crop, with applications ranging from medicinal compounds to seed oil and fibre products. Cannabis sativa is a short‐day plant, and its flowering is highly controlled by photoperiod. However, substantial genetic variation exists for photoperiod sensitivity in C. sativa , and photoperiod‐insensitive (“autoflower”) cultivars are available. Using a bi‐parental mapping population and bulked segregant analysis, we identified Autoflower2 , a 0.5 Mbp locus significantly associated with photoperiod‐insensitive flowering in hemp. Autoflower2 contains an ortholog of the central flowering time regulator FLOWERING LOCUS T ( FT ) from Arabidopsis thaliana which we termed CsFT1 . We identified extensive sequence divergence between alleles of CsFT1 from photoperiod‐sensitive and insensitive cultivars of C. sativa , including a duplication of CsFT1 and sequence differences, especially in introns. Furthermore, we observed higher expression of one of the CsFT1 copies found in the photoperiod‐insensitive cultivar. Genotyping of several mapping populations and a diversity panel confirmed a correlation between CsFT1 alleles and photoperiod response, affirming that at least two independent loci involved in the photoperiodic control of flowering, Autoflower1 and Autoflower2 , exist in the C. sativa gene pool. This study reveals the multiple independent origins of photoperiod insensitivity in C. sativa , supporting the likelihood of a complex domestication history in this species. By integrating the genetic relaxation of photoperiod sensitivity into novel C. sativa cultivars, expansion to higher latitudes will be permitted, thus allowing the full potential of this versatile crop to be reached.
Hemp ( Cannabis sativa L.) is an extraordinarily versatile crop, with applications ranging from medicinal compounds to seed oil and fibre products. Cannabis sativa is a short-day plant, and its flowering is tightly controlled by photoperiod. However, substantial genetic variation exists for photoperiod sensitivity in C. sativa, and photoperiod-insensitive (“autoflower”) cultivars are available.
Using a bi-parental mapping population and bulked segregant analysis, we identified Autoflower2 , a 0.5 Mbp locus significantly associated with photoperiod-insensitive flowering in hemp. Autoflower2 contains an ortholog of the central flowering time regulator FLOWERING LOCUS T ( FT ) from Arabidopsis thaliana which we termed CsFT1 . Extensive sequence divergence between alleles of CsFT1 was identified between photoperiod-sensitive and insensitive cultivars of C. sativa , including a duplication of CsFT1 and sequence differences especially in introns. Genotyping of several mapping populations and a diversity panel confirmed a strong correlation between CsFT1 alleles and photoperiod response as well as affirming that at least two independent loci for this agriculturally important trait, Autoflower1 and Autoflower2 , exist in the C. sativa gene pool.
This study reveals the multiple independent origins of photoperiod insensitivity in C. sativa, supporting the likelihood of a complex domestication history in this species. By integrating the genetic relaxation of photoperiod sensitivity into novel C. sativa cultivars, expansion to higher latitudes will be permitted, thus allowing the full potential of this versatile crop to be reached.
