Integrated metabolomic and transcriptomic analysis revealed the regulation of yields, cannabinoid, and terpene biosynthesis in Cannabis sativa L. under different photoperiods

Photoperiods affect plant flowering, organ formation, and metabolite synthesis. Cannabis sativa L., renowned as one of the world's oldest medicinal plants, primarily derives its medicinal properties from secondary metabolites. However, the intricate mechanisms underlying the response of C. sativa to different photoperiods remain poorly studied and reported. This study aimed to elucidate, for the first time, the effects of varied photoperiods on C. sativa after a 28 d vegetative growth period, particularly on the regulation of yield, cannabinoid, and terpenes. The results showed that the yield and cannabinoid levels of C. sativa were hypersensitive to photoperiod. Integrated analyses combining metabolomics and transcriptomics unveiled the intricate response mechanisms of C. sativa to diverse photoperiods. Kyoto Encyclopedia of Genes and Genomes analysis revealed the phenylpropanoid biosynthesis pathway as having the highest concentration of differentially accumulated metabolites (DAMs) and differentially expressed genes (DEGs), crucial for the synthesis of medicinal compounds. Photosynthesis and plant hormones directly determined yield, with 18 DEGs and two DAMs (indole-3-acetic acid and salicylic acid) playing pivotal roles in the regulation of the yield. DXR, OAC, and THCAS regulated cannabinoid synthesis, CsTPS regulated terpene synthesis. Furthermore, glandular trichomes and transcription factors, including bHLH and MYB, emerged as significant regulators in cannabinoid and terpene synthesis. In summary, this study provides a theoretical and practical reference for the optimal photoperiod to improve plant yield and quality of C. sativa.