## 3 Results and Discussion
### Correlations between Core Functional Microbial Community and Characteristic Flavor Compounds
VIP plot of the microbiota using O2 PLS modeling during black rice wine fermentation of Q1 (**a**), Q2 (**b**) and Q3 (**c**) Xiaoqu (red, VIP \(>\) 1.0, \(p\) \(<\) 0.05); Correlation network of Q1 (**d**), Q2 (**e**) and Q3 (**f**) Xiaoqu were constructed using [PERSON]’s correlation coefficient (\(\,\mid\!\!r\!\mid\,>0.6\), \(p\)\(<\) 0.05) among the microbial community (20 top fungi and 50 top bacteria) and the 18 characteristic flavor substances (OAV \(\geq\) 1: isoamyl acetate (et5), ethyl octanoate (et10), 2-octanal (ad5), ethyl decanoate (et17), 2-decneal (ad9), ethyl heptanoate (et8), ethyl butyrate (et3), and nonanal (ad6); 1 \(>\) OAV \(>\) 0.1: ethyl palmit (et22), phenyl ethyl acetate (et13), phenyl ethanol (al11), limonee (hf1), ethyl acetate (et1), 4-ethyl guaiacol (bp3), isoamyl alcohol (al2), butylolactone (et7), and ethyl cinnamate (et18)) in black rice wine. To further clarify the core functional microbiota that plays a major role in characteristic flavor substances and the overall aroma flavor substances of BRW, screening would be based on the following criteria [36]: (1) the VIP value of the microbial genus was >1.0; (2) the correlation coefficient (r) between microbial genera and at least 10 characteristic flavor substances was >0.6 (_p_ < 0.05). As a result (Table 2), the core functional microbiota responsible for producing aroma in Q1 were _Wickerhamomyces_, _Saccharomyces_, and _Pediococcus_; Q2 included _Wickerhamomyces_, _Issatchenkaia_, _Wallemia_, _Pediococcus_, _Weissella_, and _Lactobacillus_; Q3 comprised _Schizosaccharomyces_, _Saccharomyces_, _Wickerhamomyces_, _Candida_, _Cyberlindnera_, _Wallemia_, _Clavispora_, and _Pediococcus_, with _Wickerhamomyces_ and _Pediococcus_ being the common functional strains. Generally, _Saccharomyces cerevisiae_, non-Saccharomyces yeasts and LAB were the major microorganisms that contributed to the flavor of BRW, and these were also found as core functional microbial groups in other fermented foods, such as Pu'er tea, soybean, etc. [23; 37]. _Saccharomyces cerevisiae_ can produce large amounts of ethanol, esters, and other flavor compounds [38]. Furthermore, it has been found to have a considerable positive correlation with the majority of volatile flavor compounds in this study. Yet, its contribution to ethanol and other volatile flavor compounds may be limited, due to its extremely low abundance (<0.1%). Consequently, when examining the core functional microorganisms responsible for producing characteristic volatile substances, it is essential to take into account both the abundance and functions [39]. Recent studies have revealed that non-Saccharomyces yeasts (such as _Wickerhamomyces_) may yield higher concentrations of alcohols and esters than _Saccharomyces cerevisiae_, and this study also discovered comparable results [40]. These implied that _Wickerhamomyces_ was likely to be a major contributor to ethanol accumulation and the formation of volatile flavor compounds. Lactic acid bacteria, which include _Pediococcus_, _Weissella_, and _Lactobacillus_, are actively involved in many foods' fermentation, not only imparting a pleasant flavor and nutritional value [41; 42], but also restraining the growth of pathogenic bacteria and spoilage bacteria by producing antibacterial substances like lactic acid and bacterioxins [43; 44], thereby achieving \"self-purification\" in the fermentation environment [23]. In this research, all Xiaous had varying amounts of food-borne pathogenic bacteria--_Enterobacter_--[45] but the extensive reproduction of LAB generated a large number of organic acids, thus reducing the number of _Enterobacter_ and eventually eradicating them from the fermentation environment. To sum up, the production of black rice wine may involve two primary steps: (1) during the saccharification stage, _Saccharomyces_ and unclassified_f_Metschnikowiaceae were responsible for breaking down macromolecular substances from various enzymatic hydrolysis materials, supplying precursor substances for the growth of bacteria and yeast.