高通量测序分析大兴安岭典型森林土壤细菌和真菌群落特征

Characteristics of soil bacterial and fungal community of typical forest in the Greater Khingan Mountains based on high-throughput sequencing

摘要:

【背景】大兴安岭地区是我国对气候变化响应最敏感的区域，而土壤微生物在维持寒区森林生态系统结构和功能中发挥重要作用。【目的】探究大兴安岭不同森林类型土壤微生物群落结构及与环境因子的关系。【方法】采用Illumina Miseq高通量测序技术，分析3种典型森林(白桦林、落叶松林和樟子松林)土壤细菌和真菌群落组成和多样性。【结果】 3种林型中共获得2 786个细菌操作分类单元(Operational Taxonomic Unit，OTU)，隶属于38门531属，其中优势菌门为变形菌门(Proteobacteria，31.45%?40.32%)、酸杆菌门(Acidobacteria，14.24%?40.16%)和放线菌门(Actinobacteria，7.13%?22.15%)；1 803个真菌OTU隶属于8门263属，其中优势菌门为担子菌门(Basidiomycota，40.43%?62.75%)和子囊菌门(Ascomycota，35.81%?53.68%)。主坐标分析表明，3种林型中细菌和真菌群落组间差异远大于组内差异。Mantel检验结果显示：细菌群落结构与pH、总氮(Total Nitrogen，TN)、总磷(Total Phosphorus，TP)和含水量(Soil Water Content，SWC)具有显著相关性(P<0.05)，其中pH的相关性系数最大；真菌群落结构与SWC、TN和TP具有显著相关性(P<0.05)，其中TN的相关性系数最大。冗余分析结果发现，TP与变形菌门、担子菌门相对丰度呈显著正相关，TN和SWC与酸杆菌门、子囊菌门呈显著正相关，pH与放线菌门呈显著正相关(P<0.05)。【结论】不同林型间土壤微生物群落结构存在显著差异，明晰其分布规律及主要环境驱动因子，是把握寒区森林生态系统过程的关键。

Abstract:

[Background] The high latitude permafrost area in the Greater Khingan Mountains is the most sensitive region to climate change in China, and soil microorganisms play an essential role in maintaining the structure and function of forest ecosystem in the cold region. [Objective] In order to explore the soil microbial community structure of different forest types and its relationship with environmental factors in permafrost region of Greater Khingan Mountains. [Methods] Illumina Miseq high-throughput sequencing technology was applied to analyze the composition and diversity of soil bacterial and fungal communities in three typical forests (Larix gmelinii, Pinus sylvestris var. mongolica and Betula platyphlla). [Results] A total of 2 786 bacterial OTUs (Operational taxonomic units, OTUs) were obtained from three forest types, belonging to 38 phyla and 531 genera, of which the dominant phyla were Proteobacteria (31.45%?40.32%), Acidobacteria (14.24%?40.16%) and Actinobacteria (7.13%?22.15%); 1 803 fungal OTUs belong to 8 phyla and 263 genera with dominant phyla being Basidiomycota (40.43%?62.75%) and Ascomycota (35.81%?53.68%). Principal coordinate analysis showed that the differences between groups of bacterial and fungal communities were much greater than those within groups. Mantel test showed that the bacterial community structure was significantly correlated with pH, total nitrogen (TN), total phosphorus (TP) and soil water content (SWC) (P<0.05), and the correlation coefficient of pH was the largest. The fungal community structure was significantly correlated with SWC, TN and TP (P<0.05), and TN had the highest correlation coefficient. The results of redundancy analysis showed that the relative abundance of Proteobacteria and Basidiomycota was significantly positively correlated with TP. SWC and TN had a very significant positive correlation with the relative abundance of Acidobacteria and Ascomycota, and pH was positively relative to the Actinobacteria (P<0.05). [Conclusion] There are significant differences in soil microbial community structure among different forest types. Clarifying their distribution and main environmental driving factors are the key to grasp the process of forest ecosystem in cold regions.