The differential expression of the two key genes involved in fructan biosynthetic pathway in artichoke vs. wild cardoon improves inulin-type fructans

The artichoke (Cynara cardunculus subsp. scolymus) is an intriguing source of indigestible sugar polymers such as inulin-type fructans. Artichoke represents an important component of a traditional Mediterranean diet and its edible parts are a good source of many high added value compounds such as inulin, a polymer showing relevant prebiotic properties. Compared to the cultivated varieties, the wild cardoon (C. cardunculus var. sylvestris) growing naturally under harsh conditions and well-adapted to many marginal areas, could have a good potential for use in sustainable production in stressed lands. Here, we evaluated by enzymatic assay, the amount of inulin-type fructans both in artichoke and wild cardoon in the two different organs, heads and rhizomes. The expression pattern of the genes encoding the two key enzymes sucrose:sucrose 1-fructosyltransferase and fructan 1-fructosyltransferase, involved in fructan biosynthesis, have been also evaluated. Our results showed that the amount of inulin-type fructans was higher in the wild cardoon than in the artichoke heads, together with a higher expression of the two key genes involved in the fructan biosynthetic pathway. A conspicuous content of inulin-type fructans was found also in the rhizome, supporting the significant role of these compounds in the storage and in protection from cold and/or winter stresses.