Transcriptome profiling of sanitized artichoke ecotypes and characterization of genes involved in the biosynthesis of secondary metabolites.

Globe artichoke (Cynara cardunculus L. var. scolymus) is gaining commercial interest for the high content of healthpromoting bioactive compounds (BACs) such as inulin, polyphenols and antioxidant molecules. Availability of ecotypes sanitized by viral and fungal infections, characterized by vegetative vigor, productivity and quality has relaunched the crop in the market. We report the effect of sanitation protocol, based on in vitro culture and thermotherapy, on BACs accumulation by transcriptomic analysis of two late flowering artichoke ecotypes Locale di Mola tardivo and Troianella. The analysis highlighted remarkable differences in genetic, environmental information processing and primary cell metabolisms between sanitized and wild-type plants with about 2% of differentially expressed genes (DEGs) mainly involved in biosynthesis of phenylpropanoid, carotenoid and other secondary metabolites. Comparison between the two sanitized ecotypes showed only 75 DEGs, with respect to a higher percentage of DEGs between wild-type ecotypes. This difference could be related to plant response and oxidative burst against pathogen infection in wild-type plants. BACs analysis by HPLC–DAD showed a significant decrease of polyphenols accumulation in sanitized-plants compared to wild-type, speculating a different modulation of the biosynthetic pathway by sanitation protocol. A different response of the two ecotypes was also observed by the analysis of peroxidase activity. A similar approach is being conducted on the early flowering ecotype Brindisino. This study represents the unique investigation of transcriptome profile and BACs accumulation in artichoke ecotypes exposed to sanitation protocol and aims to promote the soilless cultivation of vigorous and pathogen-free artichokes, even for BACs extraction.