同一地区中温和高温大曲理化性质及真菌群落组成的比较研究

A Comparative Study on Physicochemical Indices and Fungal Community Composition of Medium-temperature and Hightemperature Daqus from the Same Region

为减少季节、地域等因素的干扰,探究不同顶温控制策略对大曲真菌群落的影响,本研究主要运用高通量测序技术对采集自同一优质白酒核心产区的中温及高温大曲的真菌群落进行了解析与比较,并结合冗余分析评估了大曲真菌群落与主要理化指标间的相关性。结果表明,高温大曲整体真菌数量(由ITS1区rDNA拷贝数表征)少于中温大曲,但前者中的真菌群落在丰富度、多样性、均匀度上整体高于后者。嗜热子囊菌属(Thermoascus)、毕赤酵母菌属(Pichia)、曲霉菌属(Aspergillus)、根霉菌属(Rhizopus)在中温大曲中占比更高,其中以橙色嗜热子囊菌(Thermoascus aurantiacus)为绝对优势菌;嗜热丝孢菌属(Thermomyces)、埃默森罗萨氏菌属(Rasamsonia)、红曲霉菌属(Monascus)、丝衣霉菌属(Byssochlamys)在高温大曲中占比更高,其中以疏绵状嗜热丝孢菌(Thermomyces lanuginosus)为绝对优势菌。根据随机森林预测模型,最能解释两类大曲菌群差异的前十个关键ASV分别归属于坚脆嗜热子囊菌(Thermoascus crustaceus)(5个)、Thermomyces spp.(4个)、Thermoascus aurantiacus(1个)三大类群。冗余分析结果显示,在两类大曲中,Aspergillus、Rasamsonia、生丝毕赤酵母属(Hyphopichia)均与糖化力呈正相关,Pichia均与酸度呈强正相关,Thermoascus均与水分呈现强正相关。本研究进一步明确了不同发酵顶温大曲的真菌群落多样性及标志物种,另探究了大曲真菌群落与主要理化指标的相关性,为制曲工艺优化和功能菌株筛选提供了参考。

In order to reduce the interference of seasonal,geographical and other factors and explore the effect of different peak-temperature control strategies on the fungal community of Daqu,this study mainly applied the high-throughput sequencing technology to analyze and compare the fungal community in medium-temperature and high-temperature Daqus collected from the same core production region of high-quality Baijiu.The correlation between the fungal community in Daqu and the main physicochemical indices was also evaluated by combining redundancy analysis.The results showed that the overall population of fungi(characterized by the copy numbers of ITS1 region of rDNA)in high-temperature Daqu was smaller than that in medium-temperature Daqu,but the richness,diversity,and evenness of overall fungal community in the former were higher than that in the latter.Thermoascus,Pichia,Aspergillus and Rhizopus accounted for a higher proportion in medium-temperature Daqu,with Thermoascus aurantiacus as the absolute advantage.Thermomyces,Rasamsonia,Monascus,and Byssochlamys accounted for a higher proportion in high-temperature Daqu,with Thermomyces lanuginosus as the absolute advantage.Based on the random forest prediction model,the first ten key ASVs that could best explain the differences between the two Daqu communities belonged respectively to three major groups including Thermoascus crustaceus(for 5 ASVs),Thermomyces spp.(for 4 ASVs),and Thermoascus aurantiacus(for 1 ASV).The results of redundancy analysis showed that Aspergillus,Rasamsonia and Hyphopichia in two types of Daqu had a positive correlation with saccharifying power,Pichia had a strong positive correlation with acidity,and Thermoascus had a strong positive correlation with moisture.This study further clarified the diversity of fungal community and biomarkers in Daqus with different peak-temperatures,explored the correlation between the fungal community in Daqu and the main physicochemical indices,and provided a reference for the optimization of Daqu making process and the screening of functional strains.