# Releasing the Full Potential of Cannabis through Biotechnology
###### Abstract  
Cannabis (_Camabis sativa_ L.) is a diocious plant cultivated worldwide for thousands of years. Besides the narcotic and therapeutic effects, Cannabis can be used as raw materials in multiple fields, including bioenergy, textiles, food, and ecological restoration. It is also an efficient bioremediation agent for contaminated soil, as well as greenhouse gas absorption. With the expansion of the market, there has been an increased demand to develop Cannabis cultivars with enhanced traits. As a major science breakthrough, the advent of the CRISPR/Cas system will revolutionize the basic and applied research in Cannabis. This article provides an overview of the recent advances in the optimization of a transformation system and in the gene editing of Cannabis. To achieve the full potential of this environmentally friendly and sustainable crop, we highlight future directions of genetic modification as well as several bottlenecks to overcome. Cannabis sativa L.; gene editing; CRISPR/Cas system  
integral membrane protein cannabigerolic acid synthase (CBGAS) performed this reaction in the membranes of the plastids [12; 13]. Finally, tetrahydroconnabinolic acid (THCA) and cannabidiolic acid (CBDA) are produced from the oxidative cyclization of CBGA. These reactions are catalyzed by the tetrahydroconnabinolic acid synthase (THCAS) and cannabidiolic acid synthase (CBDAS), respectively. Besides, these enzymes are identified in the secretory cavities of glandular trichomes, suggesting the exportation of CBGA through the membranes by diffusion or active transport [14; 15]. THCAS and CBDAS showed 83% similarity in the genome sequence, which indicates a common ancestor between them [16]. More recently, it was demonstrated that THCAS evolved from CBDAS through duplication and divergence mutations, which gave rise to the production of THCA instead of CBDA [17]. Another phenomenon that suggests they have a common ancestor is that both THCAS and CBDAS produced the same products (CBDA and THCA) at different ratios, depending on how to cyclize the C10 geranyl moiety in the same substrate (CBGA) [18]. One chemical bond was formed between C10 and C60 of the geranyl moiety in CBGA to produce CBDA. In the THCA production, Tyr484 in THCAS protein extracts the proton on O60\({}^{\prime}\), which leads to the formation of two chemical bonds [16]. Finally, CBGA, the first branch-point in the cannabinoid biosynthetic pathway, serves as a common substrate to produce several cannabinoids such as CBDA, THCA or cannabichromenic acid (CBCA), which is achieved by cyclizing the C10 moiety from GPP via independent synthases. Out of these cannabinoid syntheses identified, THCAS is the most well-studied cannabinoid synthase followed by CBDAS [19]. The crystallized THCAS and CBDAS have been isolated, purified and expressed in insect cells and cell-free systems [16; 20; 21]. In addition, [PERSON] et al. (2021) conducted a study on the domestication history of cannabis using 110 different cannabis germplasm and found that farmers' intensive selection to increase fiber yield or psychoactive properties caused Cannabis to lose the complete sequence encoding THCAS or CBDAS, respectively [22]. Both phytocannabinoids and endocannabinoids are recognized as ligands for downstream signaling to regulate diverse physiological processes by G protein-coupled receptors (GPCRs). In recent years, Class A GPCRs CB1 and CB2 have caused extensive concern as cannabinoid receptors. CB1 shares 44% sequence similarity with CB2 [23; 24; 25]. Although phylogenetically related, the distribution of CB1 and CB2 are different [26]. CB1 is located all over the human organs as well as the central nervous system, while CB2 is usually found in the immune system and very scarcely in the nervous system [27]. This difference has been supposed to be the leading cause that most side effects of cannabinoids come from CB1 activation [26; 28].