常州市春季PM2.5中细菌群落特征及影响因素

为研究常州市春季PM_2.5中细菌群落特征，利用高通量测序对PM_2.5中细菌的16S rRNA基因进行研究.测序获得的有效序列数为600150，以97%的相似水平划分，各样品的OTUs为1890~6519，同时样本的Coverage指数较高，表明测序结果可以准确地代表样本中的空气细菌群落.物种注释结果表明：常州春季PM_2.5中相对丰度> 1%的有11个细菌门、14个细菌纲和12个细菌属，其中变形菌门（Proteobacteria）、蓝藻细菌门（Cyanobacteria）和厚壁菌门（Firmicutes）是排名前3的优势细菌类群，占总基因丰度的80.88%.属水平优势细菌主要有拟甲色球藻属（Chroococcidiopsis，6.03%）、Rubellimicrobium（5.95%）、微囊藻属（Microcystis，4.86%）和鞘氨醇单胞菌属（Sphingomonas，3.16%），但在属水平上未能进行分类的基因序列比例高达81.11%.基于PM_2.5中细菌群落组成进行来源分析，发现常州市春季PM_2.5中细菌的环境来源多变，其主要环境源可能为淡水，其次是土壤、植物和人为源.利用冗余分析探讨环境因子与细菌群落的关系，结果表明，NH₄⁺、NO₃^-、O₃、SO₄^2-、OC、气压和CO是常州市春季PM_2.5中细菌群落的主要影响因子，同时不同环境因子对不同细菌类群影响不同.

Characteristics and influence factors of airborne bacterial communities in Changzhou's PM2.5 samples during spring

In order to investigate the characteristics of the airborne bacterial community in Changzhou's PM_2.5samplesduring spring, the 16S rRNA gene of bacterial in PM_2.5 sampleswas studied by high-throughput sequencing. 600150sequences obtained could be divided into 1890~6519 OTUs of each sample at 97% similarity level. The Coverage index of the samples was high and could accurately represent the airborne bacterial community in the samples. Species annotation results indicated that there were 11bacterial phyla, 14bacterial classes, 12bacterial genera with relative abundance greater than 1% in Changzhou's PM_2.5 samples during spring. Proteobacteria, Bacteroidetes and Firmicutes were the top 3dominant phyla, accounting for 80.88% of the total gene abundance. At the genus level, Chroococcidiopsis (6.03%), Rubellimicrobium (5.95%), Microcystis (4.86%) and Sphingomonas (3.16%) were predominant, but the proportion of gene sequences that failed to be classified was up to 81.11%. Based on the source analysis of bacterial community composition in PM_2.5, it was found that the environmental sources of bacteria in Changzhou's PM_2.5 samples during spring were varied, and the main environmental source might be fresh water, followed by soil, plants and anthropogenic sources. The results of redundancy analysis (RDA) for the relationship between environmental factors and bacterial community showed that NH₄⁺, NO₃^-, O₃, SO₄^2-, OC, air pressure and CO were the main environmental factors affecting the bacterial community in Changzhou's PM_2.5 samplesduring spring. At the same time, varied environmental factors had different effects on bacterial groups.