Hormonal control of promoter activities of Cannabissativa prenyltransferase 1 and 4 and salicylic acid mediated regulation of cannabinoid biosynthesis

Cannabissativa aromatic prenyltransferase 4 (CsPT4) and 1 (CsPT1) have been shown to catalyze cannabigerolic acid (CBGA) biosynthesis, a step that rate-limits the cannabinoid biosynthetic pathway; both genes are highly expressed in flowers. CsPT4 and CsPT1 promoter driven beta-glucuronidase (GUS) activities were detected in leaves of cannabis seedlings, and strong CsPT4 promoter activities were associated with glandular trichomes. Hormonal regulation of cannabinoid biosynthetic genes is poorly understood. An in silico analysis of the promoters identified putative hormone responsive elements. Our work examines hormone-responsive elements in the promoters of CsPT4 and CsPT1 in the context of physiological responses of the pathway to the hormone in planta. Dual luciferase assays confirmed the regulation of promoter activities by the hormones. Further studies with salicylic acid (SA) demonstrated that SA pretreatment increased the expression of genes located downstream of the cannabinoid biosynthetic pathway. The results from all aspects of this study demonstrated an interaction between certain hormones and cannabinoid synthesis. The work provides information relevant to plant biology, as we present evidence demonstrating correlations between molecular mechanisms that regulate gene expression and influence plant chemotypes.

Automated summary

Cannabissativa aromatic prenyltransferase 4 (CsPT4) and 1 (CsPT1) play a crucial role in catalyzing the biosynthesis of cannabigerolic acid (CBGA) in cannabis plants. These genes are highly expressed in flowers, and their promoters exhibit activity in leaves and glandular trichomes. This study investigates the hormonal regulation of CsPT4 and CsPT1 promoters and their impact on cannabinoid synthesis. The findings suggest an interaction between hormones and cannabinoid synthesis, providing insights into plant biology and gene expression regulation.