摘要:冻土是气候变化的敏感区，冻土中细菌对于预测冻土和气候之间的潜在反馈机制至关重要，研究冻土区土壤中细菌的多样性和种群结构将有助于及时检测环境变化并采取有效的应对措施。以黑龙江省表层冻土为研究对象，运用Illumina MiSeq高通量测序分析技术，系统分析黑龙江表层冻土细菌群落结构组成和功能特征，探究影响因素。结果表明，得到的785640条原始序列可划分为30个门，109个纲，209个目，326个科，512个属，598个种。优势菌门主要包括Proteobacteria、Actinobacteria、Acidobacteria、Chloroflexi、Bacteroidetes、Verrucomicrobia，在P<0.01水平上，Proteobacteria与Actinobacteria、Chloroflexi极显著负相关，与Acidobacteria极显著正相关，Actinobacteria与Acidobacteria极显著负相关，与Chloroflexi极显著正相关，Acidobacteria和Chloroflexi之间则无显著相关性。属水平上，Aetherobacter属在各样本之间显著性差异最大，Flavobacteriu属和Burkholderia属，Microlunatus属和Massilia属之间呈现显著负相关。RDA多元回归分析发现，土壤pH是影响细菌群落结构组成的最主要因子，门水平上与Crenarchaeota、Verrucomicrobia、Thermi呈极显著正相关，与Elusimicrobia呈极显著负相关；属水平上，与Arthrobacter属、Blastococcus属、Chelatococcus属在P<0.001水平上呈现显著正相关。基于细菌基因组的16S rRNA序列对菌群代谢功能进行预测发现，细菌群落主要代谢功能表现在膜转运功能、氨基酸代谢功能以及碳水化合物代谢功能三方面。黑龙江省区域尺度范围内，表层冻土中细菌群落结构分异主要受土壤理化性质影响，而土壤利用方式对微生物群落结构影响不显著。



Abstract:Frozen soil is sensitive to climatic change. The bacteria in the frozen soil are critical to the prediction of the potential feedback mechanism between the frozen soil and the climate. Studies on the diversity and community structure of bacteria in the frozen soil are conducive to monitoring the environmental changes and taking effective measures. This study aimed to analyze the bacterial community structure of the surface frozen soil of Heilongjiang Province. The Illumina MiSeq high-throughput sequencing technology was used to systematically investigate the structural composition and functional characteristics of the bacterial community of the surface frozen soil and explore the influencing factors. The results demonstrated that the obtained 785,640 raw sequences involved 30 phyla, 109 classes, 209 orders, 326 families, 512 genera, and 598 species. The dominant bacterial phyla included mainly the Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, Bacteroidetes, and Verrucomicrobia. The Proteobacteria extremely significantly negatively correlated with Actinobacteria and Chloroflexi, but extremely significantly positively correlated with Acidobacteria (P< 0.01). The Actinobacteria extremely significantly negatively correlated with Actinobacteria, but extremely significantly positively correlated with Chloroflexi. No significant correlation was found between Acidobacteria and Chloroflexi. At the genus level, Aetherobacter showed the largest significant differences between various samples. The significantly negative correlations were observed between Flavobacterium and Burkholderia and between Microlunatus and Massilia. The multiple regression by redundancy analysis (RDA) demonstrated that the soil pH was the primary factor affecting the structural composition of the bacterial community. Furthermore, at the phylum level, the soil pH extremely significantly positively correlated with Crenarchaeota, Verrucomicrobia, and Thermi, and extremely significantly negatively correlated with Elusimicrobia. At the genus level, the soil pH significantly positively correlated with Arthrobacter, Blastococcus, and Chelatococcus (P< 0.001). Based on the 16S rRNA sequence of bacterial genome, the following three main metabolic functions of the bacterial community were predicted: membrane transport function, amino acid metabolic function, and carbohydrate metabolic function. Within the regional range of Heilongjiang Province, the structural differentiation of the bacterial community in the surface frozen soil was primarily determined by soil physicochemical properties, but not significantly affected by the soil utilization pattern.





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