Analysis of Sequence Variability and Transcriptional Profile of Genes in L. Chemotypes with a Focus on .

L. has been long cultivated for its narcotic potential due to the accumulation of tetrahydrocannabinolic acid (THCA) in female inflorescences, but nowadays its production for fiber, seeds, edible oil and bioactive compounds has spread throughout the world. However, some hemp varieties still accumulate traces of residual THCA close to the 0.20% limit set by European Union, despite the functional gene encoding for THCA synthase (THCAS) is lacking. Even if some hypotheses have been produced, studies are often in disagreement especially on the role of the cannabichromenic acid synthase (CBCAS). In this work a set of European genotypes, representative of all chemotypes, were investigated from a chemical and molecular point of view. Highly specific primer pairs were developed to allow an accurate distinction of different genes. In addition to their use as markers to detect the presence of at genomic level, they allowed the analysis of transcriptional profiles in or plants. While the high level of transcription of and () clearly reflects the chemical phenotype of the plants, the low but stable transcriptional level of in all genotypes suggests that these genes are active and might contribute to the final amount of cannabinoids.