Yang Bing, Feng Wanju, Zhou Wenjia, He Ke, Yang Zhisong
Sichuan Academy of Giant Panda, Chengdu 610041, China.
Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637002, China.
Microorganisms. 2024 Apr 3;12(4):728. doi: 10.3390/microorganisms12040728.
Although the importance of the soil bacterial community for ecosystem functions has long been recognized, there is still a limited understanding of the associations between its community composition, structure, co-occurrence patterns, and soil physicochemical properties. The objectives of the present study were to explore the association between soil physicochemical properties and the composition, diversity, co-occurrence network topological features, and assembly mechanisms of the soil bacterial community. Four typical forest types from Liziping Nature Reserve, representing evergreen coniferous forest, deciduous coniferous forest, mixed conifer-broadleaf forest, and its secondary forest, were selected for this study. The soil bacterial community was analyzed using Illumina MiSeq sequencing of 16S rRNA genes. Nonmetric multidimensional scaling was used to illustrate the clustering of different samples based on Bray-Curtis distances. The associations between soil physicochemical properties and bacterial community structure were analyzed using the Mantel test. The interactions among bacterial taxa were visualized with a co-occurrence network, and the community assembly processes were quantified using the Beta Nearest Taxon Index (Beta-NTI). The dominant bacterial phyla across all forest soils were Proteobacteria (45.17%), Acidobacteria (21.73%), Actinobacteria (8.75%), and Chloroflexi (5.06%). Chao1 estimator of richness, observed ASVs, faith-phylogenetic diversity (faith-PD) index, and community composition were distinguishing features of the examined four forest types. The first two principal components of redundancy analysis explained 41.33% of the variation in the soil bacterial community, with total soil organic carbon, soil moisture, pH, total nitrogen, carbon/nitrogen (C/N), carbon/phosphorous (C/P), and nitrogen/phosphorous (N/P) being the main soil physicochemical properties shaping soil bacterial communities. The co-occurrence network structure in the mixed forest was more complex compared to that in pure forests. The -NTI indicated that the bacterial community assembly of the four examined forest types was collaboratively influenced by deterministic and stochastic ecological processes.
尽管土壤细菌群落对生态系统功能的重要性早已得到认可，但对于其群落组成、结构、共生模式与土壤理化性质之间的关联，人们的了解仍然有限。本研究的目的是探讨土壤理化性质与土壤细菌群落的组成、多样性、共生网络拓扑特征及组装机制之间的关联。本研究选取了栗子坪自然保护区的四种典型森林类型，分别代表常绿针叶林、落叶针叶林、针阔混交林及其次生林。采用Illumina MiSeq对16S rRNA基因进行测序，分析土壤细菌群落。基于Bray-Curtis距离，利用非度量多维尺度分析来说明不同样本的聚类情况。采用Mantel检验分析土壤理化性质与细菌群落结构之间的关联。通过共生网络可视化细菌分类群之间的相互作用，并使用Beta最近分类群指数（Beta-NTI）对群落组装过程进行量化。所有森林土壤中主要的细菌门为变形菌门（45.17%）、酸杆菌门（21.73%）、放线菌门（8.75%）和绿弯菌门（5.06%）。丰富度的Chao1估计值、观测到的可操作分类单元（ASVs）、谱系多样性（faith-PD）指数和群落组成是所研究的四种森林类型的显著特征。冗余分析的前两个主成分解释了土壤细菌群落41.33%的变异，土壤总有机碳、土壤湿度、pH值、总氮、碳氮比（C/N）、碳磷比（C/P）和氮磷比（N/P）是塑造土壤细菌群落的主要土壤理化性质。与纯林相比，混交林的共生网络结构更为复杂。Beta-NTI表明，所研究的四种森林类型的细菌群落组装受到确定性和随机生态过程的共同影响。
