# Yeast Diversity during Spontaneous Fermentations and  
Oenological Characterisation of Indigenous _Saccharomyces cerevisiae_ for Potential as Wine Starter Cultures  
[PERSON]  
1 College of Enology, Northwest A & F University, Yangling, Xianyang 712100, China;  
[EMAIL_ADDRESS] (Y.C. ); [EMAIL_ADDRESS] (Y.J. ); [EMAIL_ADDRESS] (Y.S. );  
[EMAIL_ADDRESS] (X.Z. ); [EMAIL_ADDRESS] (G.W. ); [EMAIL_ADDRESS] (Y.P. ); [EMAIL_ADDRESS] (Y.S.) [PERSON]  
1 College of Enology, Northwest A & F University, Yangling, Xianyang 712100, China;  
[EMAIL_ADDRESS] (Y.C. ); [EMAIL_ADDRESS] (Y.J. ); [EMAIL_ADDRESS] (Y.S. );  
[EMAIL_ADDRESS] (X.Z. ); [EMAIL_ADDRESS] (G.W. ); [EMAIL_ADDRESS] (G.W. ); [EMAIL_ADDRESS] (Y.P. ); [EMAIL_ADDRESS] (Y.S.) [PERSON]  
1 College of Enology, Northwest A & F University, Yangling, Xianyang 712100, China;  
[EMAIL_ADDRESS] (Y.C. ); [EMAIL_ADDRESS] (Y.J. ); [EMAIL_ADDRESS] (Y.S. );  
[EMAIL_ADDRESS] (X.Z. ); [EMAIL_ADDRESS] (G.W. ); [EMAIL_ADDRESS] (G.W. ); [EMAIL_ADDRESS] (G.W. ); [EMAIL_ADDRESS] (Y.P. ); [EMAIL_ADDRESS] (Y.S.) [PERSON]  
1 College of Enology, Northwest A & F University, Yangling, Xianyang 712100, China;  
[EMAIL_ADDRESS] (Y.C. ); [EMAIL_ADDRESS] (Y.J. ); [EMAIL_ADDRESS] (Y.S. );  
[EMAIL_ADDRESS] (X.Z. ); [EMAIL_ADDRESS] (G.W. ); [EMAIL_ADDRESS] (G.  
The distribution of autochthonous yeasts can be conditioned by various \"_terroir_\" elements, encompassing topography, grape varieties, climate, anthropogenic practices, abiotic stressors during fermentation, etc. [2; 8; 10; 11]. Fertmentative yeasts _Hanseniaspora_, _Pichia_, _Metschnikowia_ and _Isstatchenkia_ are commonly found at initial stages of fermentation whilst _Saccharomyces cerevisiae_ gradually dominates the microbial community as fermentation proceeds [12; 13]. Whilst these yeasts all proffer conspicuous contributions to wine flavour and mouthfeel formation [14; 15], the uninoculated fermentations are mainly completed by the diverse populations of indigenous _S. cerevisiae_ due to its high tolerance to wine-associated stressors. The biodiversity of regional _S. cerevisiae_ and its impact on wine quality have been studied over decades, either at global or at individual strain level [11; 16; 17; 18; 19]. Many previous studies have observed intermediate to high levels of genetic divergence among autochthonous _S. cerevisiae_ isolates [16; 19; 20; 21], which is likely due to geographical attributes [22], the dynamic changes of the wine environment [23; 24], and anthropogenic practices (e.g., SO2 treatment) [25; 26]. For individual indigenous _S. cerevisiae_ isolates, the production of secondary metabolites, including desirable volatile compounds, can be strain-dependent [16; 18; 27; 28]. Recently, geographic differentiation of _S. cerevisiae_ strains has been characterised at global [5] and regional scales [8; 15; 29], revealing the distribution of distinctive populations at geographically large scales. At smaller scales, several studies investigated the biodiversity of _S. cerevisiae_ from different vineyards within the same region [30] or the same sub-region [21], and different sites within a single vineyard [3; 31; 32]. Significant genetic differences between _S. cerevisiae_ isolates at smaller scales can be driven by geographic factors [21; 30], in conjunction with grape varieties [3; 21; 31; 32]. Additionally, [PERSON] et al. [21] further suggested that the _S. cerevisiae_ population can be the main driver of wine aroma profiles at sub-regional scale. Taken together, investigation of the genetic diversity of indigenous _S. cerevisiae_ and evaluation of individual isolates for oenological traits are of high importance for selection of ideal strains that can enhance wine regional characteristics. Ningxia, which is located at 37\({}^{\circ}\)43\({}^{\prime}\)-39\({}^{\circ}\)23\({}^{\prime}\) N and 105\({}^{\circ}\)45\({}^{\prime}\)-106\({}^{\circ}\)47\({}^{\prime}\) E, is a rising and rapidly developing wine region of China with ideal climate conditions for producing premium wines.