## 4 Discussion  
In recent years, geographic distribution of microbial community of wine grapes has been investigated revealing regional microbial signatures and the geographic delineation of yeast communities with wines [21; 22]. This distribution is conditioned by several factors such as cultivar, vintage and climate and could be influenced by agricultural practices [15; 23; 24]. In addition, preliminary evidence on the association of wine microbiome and phenotype at regional level suggests a microbial contribution to regional characteristic defined as \"_terroir_\" [25; 26]. Indeed, there is preliminary evidence that yeast biota related to specific vineyard strongly influence the final wine composition [21; 27; 28; 15; 29]. Actually, the concept of the \"indigenous\" yeast is related to the preservation of microorganism naturally present in grapes and winery. In this context, we evaluated the enological aptitude of two _S. cerevisiae_ isolated from the regional winemaking areas Piceno DOC. The molecular characterization using the polymorphism of inter-\(\delta\) regions showed specific patterns of selected _S. cerevisiae_ strains isolated from Offida DOCG area in comparison with the most common _S. cerevisiae_ commercial strains tested. The same approach was used by [PERSON] et al. [30] to investigate the intraspecific genetic diversity of _S. cerevisiae_ associated with the vineyard environment. To assess the oenological aptitude of two _S. cerevisiae_ native Pe1 and G4 strains, microfermentations on natural grape juice were carried out. The influence of indigenous _S. cerevisiae_ strains on the analytical and volatile compositions of wine  
Figure 4: Principal component analysis based on the data for the volatile compounds in the wines produced by different _S. cerevisiae_ strains. The numbers 16 and 22 associated to each strain refer to the fermentation temperature (16 \({}^{\circ}\)C and 22 \({}^{\circ}\)C). was investigated for Montepulciano d'Abruzzo and Malvar winemaking areas. In both investigations, distinctive analytical profiles of wines were shown [31; 32]. In this work, the two native strains Pe1 and G4 did not differ significantly from the compared commercial strains for the main analytical characteristics. On the other hand, they showed a specific volatile profile that could be useful to further characterize Piceno DOC wines, emphasizing their aromatic composition. In this regard, we found that the fermentation temperature plays an important role on flavor of final wine. Indeed, an increase of some volatile compounds, such as isoamyl acetate, ethyl hexanoate and ethyl octanoate, in microfermentations carried out at 22 \({}^{\circ}\)C was exhibited by two indigenous strains. Similarly, a reduction of total SO\({}_{2}\) production was found at 22 \({}^{\circ}\)C in comparison with 16 \({}^{\circ}\)C fermentation trials without significant differences between the two indigenous and commercial starter strains. In conclusion, the present work emphasizes the potential use of selected indigenous _S. cerevisiae_ for the fermentation of Piceno DOC wines. In particular, these selected strains (Pe1 and G4) could be used as a suitable strategy to influence the aromatic complexity of Piceno DOC wines. Supplementary materials can be found at [[http://www.mdpi.com/2311-5637/4/2/37/s1](http://www.mdpi.com/2311-5637/4/2/37/s1)]([http://www.mdpi.com/2311-5637/4/2/37/s1](http://www.mdpi.com/2311-5637/4/2/37/s1)). **Author Contributions:** [PERSON], [PERSON], [PERSON] and F.C. contributed equally to this manuscript. All authors participated in the design and discussion of the research. [PERSON] carried out the experimental part of the work. [PERSON], [PERSON], [PERSON] and [PERSON] carried out the analysis of the data and wrote the manuscript. All the authors have read and approved the final manuscript. **Acknowledgments:** The authors thank Tenuta Cocci Grifoni di Guido Cocci Grifoni & C. S.R.L. for the financial support of the research. We thank [PERSON] for her support.