Epiphytic bacteria on the surfaces of submerged macrophytes play important roles in the growth of the host plant, nutrient cycling, and the conversion of pollutants in aquatic systems. A knowledge of the epiphytic bacterial community structure could help us to understand these roles. In this study, the abundance, diversity, and functions of the epiphytic bacterial community of Myriophyllum spicatum collected from Baiyangdian Lake in June, August, and October 2019 were studied using quantitative PCR (qPCR), high-throughput sequencing, and the prediction of functions. An analysis using qPCR showed that the epiphytic bacteria were the most abundant in October and the least abundant in August. High-throughput sequencing revealed that Proteobacteria, Gammaproteobacteria, and Aeromonas were the dominant phylum, class, and genus in all the samples. The common analyses of operational taxonomic units (OTUs), NMDS, and LDA showed that the epiphytic bacterial communities were clustered together based on the seasons. The results of a canonical correlation analysis (CCA) showed that the key water quality index that affected the changes of epiphytic bacterial community of M. spicatum was the total phosphorus (TP). The changes in abundance of Gammaproteobacteria negatively correlated with the TP. Predictive results from FAPROTAX showed that the predominant biogeochemical cycle functions of the epiphytic bacterial community were chemoheterotrophy, nitrate reduction, and fermentation. These results suggest that the epiphytic bacterial community of M. spicatum from Baiyangdian Lake varies substantially with the seasons and environmental conditions.

沉水大型植物表面的附生细菌在寄主植物的生长、养分循环和水生系统中污染物的转化中起着重要作用。对附生细菌群落结构的了解可以帮助我们理解这些作用。在这项研究中，附生细菌群落的丰度、多样性和功能狐尾藻使用定量 PCR (qPCR)、高通量测序和功能预测对 2019 年 6 月、8 月和 10 月从白洋淀湖采集的数据进行了研究。使用 qPCR 的分析表明，附生细菌在 10 月份最多，而在 8 月份最少。高通量测序显示 Proteobacteria、Gammaproteobacteria 和气单胞菌是所有样本中的优势门、纲和属。对操作分类单元 (OTU)、NMDS 和 LDA 的共同分析表明，附生细菌群落根据季节聚集在一起。典型相关分析（CCA）结果表明，影响附生细菌群落变化的关键水质指标M. spicatum是总磷（TP）。Gammaproteobacteria 丰度的变化与 TP 呈负相关。FAPROTAX 的预测结果表明，附生细菌群落的主要生物地球化学循环功能是化学异养、硝酸盐还原和发酵。这些结果表明，附生细菌群落M. spicatum 白洋淀的水量随季节和环境条件变化很大。