Genetic traceability of Asti Spumante and Moscato d'Asti musts and wines using nuclear and chloroplast microsatellite markers

The final characteristics of a wine are strongly influenced by must varietal composition. Further, wine quality and value can be heavily modified if grape varieties other than those expected/allowed are used, especially in the case of monovarietal wines. 'Moscato bianco', which is one of the main grape varieties grown in Piedmont (northwestern Italy), is used for the production of two renowned monovarietal sparkling wines: Asti Spumante and Moscato d'Asti. Here, the genetic traceability of these wines was assessed using a simple sequence repeat (SSR or microsatellite) DNA-based method. Must and wine samples from two local wineries were collected at different winemaking steps: after grape crushing and pressing, without the skins (must sample 1, M1); after static clarification or flotation (M2); halfway through fermentation (M3); and finished wines. A DNA extraction protocol was developed, and samples were analysed using a set of 9 nuclear (nSSR) and 7 chloroplast (cpSSR) markers. The application of nSSR markers was successful for M1 and M2, but was inadequate for M3 and wines. CpSSR gave better results as amplifications were achieved using DNA extracted from M1, M2 and wines, despite the lack of amplification in M3. Furthermore, the amplified cpSSR loci showed high polymorphism, allowing the identification of 5 distinct chlorotypes among 7 muscat-flavoured and 2 non-aromatic grapevines. Altogether, these results suggest that this technique could be extended to wine quality and authenticity control, as well as origin protection.