密封泡菜母水的真菌群落动态及与理化因子的相关性

Fungal community dynamics and correlations with physicochemical factors in sealed Paocai brine

摘要:

【背景】 真菌对泡菜的风味与质地发挥着重要作用，影响泡菜及母水的储存时长。母水泡菜是我国的传统泡菜制作方法，也是保持泡菜原有风味的核心技术。【目的】 解析密闭储存泡菜母水的真菌群落动态及与理化因子的关系。【方法】 采用扩增子序列变体(amplicon sequence variants, ASV)技术监测25 ℃密闭储存30 d内泡菜母水中真菌群落的动态变化，应用流动分析仪监测母水的理化因子变化。【结果】 结合泡菜母水真菌群落动态及理化因子变化，真菌群落演替在30 d内可划分为3个时期(前期为1–5 d，中期为6–16 d，后期为18–30 d)。三个时期内共注释到真菌10门39纲98目226科461属。前期真菌构成复杂且持续变化，相互作用关系密切并受pH和总氮(total nitrogen, TN)影响；中期优势属发生变化且稀有属明显增多，互作关系减弱，并受TN调控；后期稀有属持续减少，群落结构简单，互作较少并受硝态氮(nitrate nitrogen, NN)、磷酸盐(phosphates, P)和总磷(total phosphorus, TP)影响。【结论】 25 ℃密闭储存30 d的泡菜母水，其真菌群落在前、中、后3期的演替特点各不相同。25 ℃密闭储存的泡菜母水在一周内食用更安全，也能有效保障发酵泡菜的风味，冷链储存则可适当延长保存期。泡菜体系中蕴藏的丰富真菌资源值得挖掘。

关键词:扩增子测序;泡菜母水;母水储存;稀有真菌;群落演替

Abstract:

[Background] Fungi play an important role in the flavor and texture of Paocai and influence the shelf life of Paocai and its brine. Brine is the traditional method of Paocai production in China, and it is also the key for maintaining the original flavor of Paocai. [Objective] To analyze the dynamics of the fungal community and its relationship with physicochemical factors of Paocai brine in sealed storage. [Methods] The amplicon sequence variants (ASVs) were employed to monitor the dynamics of the fungal community in Paocai brine stored at 25℃ for 30 d. A flow analyzer was used to reveal the changes in physicochemical factors of the brine. [Results] According to the fungal community dynamics and physicochemical factor changes in the Paocai brine, the fungal community succession within 30 d can be divided into three stages (early:1–5 d; middle:6–16 d; late:18–30 d). A total of 461 fungal genera belonging to 226 families, 98 orders, 39 classes of 10 phyla were annotated in the three stages. In the early stage, the fungal composition was complex and changing, and the interactions were strongly influenced by pH and total nitrogen (TN). The middle stage presented changed dominant genera and increased rare genera, and the interactions were weakened and regulated by TN. In the late stage, the number of rare genera kept decreasing, and the community structure was simple, with weak interactions which were influenced by nitrate nitrogen (NN), phosphate (P), and total phosphorus (TP). [Conclusion] The fungal community in the Paocai brine stored at 25℃ for 30 d varied in the early, middle, and late stages. The Paocai brine stored at 25℃ for 30 d was safe to be used within one week and could guarantee the flavor of Paocai. Moreover, cold chain storage could adequately extend the shelf life. It is worth exploring the rich fungal resources in the Paocai system.

Key words:amplicon sequencing;Paocai brine;storage of brine;rare fungi;community succession