## 2 Materials and Methods
### Amplicon-Based Sequencing after Cellar-Scale Fermentation  
Must samples (50 mL) were taken before and after the yeast inoculation and then at 1/3 (\(\sim\)56\({}^{\circ}\)Oe), 2/3 (\(\sim\)25\({}^{\circ}\)Oe), and at the end of alcoholic fermentation. The samples were centrifuged at 3000\(\times\)\(g\) for 10 min, and the pellets were stored at \(-\)20 \({}^{\circ}\)C until DNA extraction. They were then washed in 50 mL of saline peptone water (NaCl0.8\(\%\)\(w/v\), casein peptone 0.1\(\%\)\(w/v\), pH 7.1) and decanted by centrifugation (5 min, 200\(\times\)\(g\) 4 \({}^{\circ}\)C). Regarding the supernatant, 10 mL was used for DNA extraction and centrifuged for 30 min at 4000\(\times\)\(g\) at 4 \({}^{\circ}\)C. Pellets were resuspended in an 800 uL buffer (25 mM EDTA, 0.125 M Tris-HCl pH 8, 2 M NaCl), and cells were disrupted in a Bead Ruptor 12 (OMNI International Inc., Kennesaw, GA, USA) with 0.1 g of 0.1 mm zirconia beads (OPS Diagnostics, Lebanon,NJ, USA) for 1 min at high speed. Then, 0.2 mL of cetyltrimethylammonium bromide (CTAB) 10% _w/v_ was added and mixed before incubation at 60 \({}^{\circ}\)C for 30 min. After centrifugation (5 min at 16,400\(\times\)_g_), 0.7 mL of supernatant was transferred, and 0.5 mL of chloroform/isoamyl alcohol at a ratio of 24:1 was added and centrifuged for 15 min at 16,400\(\times\)_g_ at 4 \({}^{\circ}\)C. Finally, 0.2 mL of upper phase was processed on the BioRobot(r) EZ1 workstation (Qiagen, Hilden, Germany) using the EZ1 DNA Tissue Kit (Qiagen). Genomic DNA was eluted in a volume of 100 \(\upmu\)L and the concentration was measured using a NanoDrop(r) ND-1000 spectrophotometer (NanoDrop Technologies, Thermo Fisher Scientific, Waltham, MA, USA). Amplicon libraries were prepared using the two-step unidirectional fusion method (Thermo Fisher). PCR of the partial translation elongation factor 1-\(\upmu\)C (TEF1\(\upmu\)A) was performed in 50-\(\upmu\)L reactions using 5 \(\upmu\)L of DNA, 0.1 \(\upmu\)M of each primer (UnivSeq_EF983F, UnivSeq_983F2, UnivSeq_1567R, and UnivSeq_1576 RP, Table 1), 25 \(\upmu\)L of Platinum(tm) PCR SuperMix High Fidelity (Thermo Fisher), and 10 uL of SuperFi GC Enhancer (Thermo Fisher Scientific). Amplification was performed as follows: 98 \({}^{\circ}\)C for 30 s, followed by 20 cycles of 98 \({}^{\circ}\)C for 15 s, 55 \({}^{\circ}\)C for 30 s, 72 \({}^{\circ}\)C for 30 s, and a final extension at 72 \({}^{\circ}\)C for 5 min. All amplicons were purified using the GeneRead size selection kit (Qiagen). The second PCR step was performed in 25-\(\upmu\)L reactions using 2.5 \(\upmu\)L of amplicon, 0.1 \(\upmu\)M of primer Univ_ABCx, and 0.1 \(\upmu\)M of primer Univ_trP1, 12.5 \(\upmu\)L of Platinum(tm) PCR SuperMix High Fidelity, and 5 \(\upmu\)L of SuperFi GC Enhancer (Table 1). Amplification was performed as follows: 98 \({}^{\circ}\)C for 30 s, followed by 21 cycles of 98 \({}^{\circ}\)C for 15 s, 72 \({}^{\circ}\)C for 30 s, and a final extension at 72 \({}^{\circ}\)C for 5 min. Quality control and quantification of the amplicon library were performed using an Agilent 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA) and the High Sensitivity DNA assay. All amplicons were then pooled equimolarly, purified using the GeneRead size selection kit, and diluted to a final library concentration of 50 pM. Template preparation, chip loading, and sequencing were performed according to the manufacturer's instructions using the Ion 520(tm) and Ion 530(tm) Ext Kit-Chef and an Ion530 Chip (Thermo Fisher). The raw sequences, were primer trimmed and quality filtered (maxEE = 15, truncQ = 6, maxN = 0, n = 1 \(\times\) 10\({}^{5}\), minLen = 100, max-Len = 600) in DADA2. Amplicon sequence variances (ASVs) were obtained in DADA2 with the parameter POOL = \"pseudo\". Taxonomic annotation was performed manually using Blast programs developed by [PERSON] et al. [23].