印度块菌-云南松菌根际土壤细菌的种群组成和群落结构

以印度块菌-云南松菌根际土壤细菌为研究对象,研究其种群组成和结构特征。(1)稀释平板法分离得到印度块菌-云南松菌根际土壤细菌的纯培养菌株,对菌株的16S rRNA序列测序分析,对测序的菌株数量和得到的OTUs数量绘制物种累积曲线,当物种累积曲线趋于平缓时,对OTUs进行系统发育分析,揭示可培养细菌的种群组成和结构特征。(2)对印度块菌-云南松菌根际土壤细菌16S rRNA基因的V3—V4区进行高通量测序,分析全部细菌类群的种群组成和结构特征。(1)分离得到菌根际可培养细菌793株,分属于3个属的61个OTUs,其中假单胞菌属(Pseudomonas)序列占总序列的86%,不动杆菌属(Acinetobacter)序列占总序列的9.8%,链霉菌属(Streptomyces)序列占总序列的6.5%。假单胞菌是印度块菌-云南松菌根际土壤可培养细菌的绝对优势类群。(2)高通量测序得到菌根际细菌序列8937条,分属于20个门、198属、2073个OTUs。隶属于变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和酸杆菌门(Acidobacteria)的OTUs占总OTUs的65.9%,变形菌门、放线菌门和酸杆菌门细菌是印度块菌-云南松菌根际土壤细菌的优势细菌。隶属于黄杆菌属(Flavobacterium)、根瘤菌属(Rhizobium)和假黄色单胞菌属(Pseudoxanthomona)的OTUs占总OTUs的33%,黄杆菌属、根瘤菌属和假黄色单胞菌属细菌是印度块菌-云南松菌根际土壤细菌的优势属。印度块菌-云南松菌根际土壤可培养细菌多样性较低,假单胞菌属细菌占据绝对优势地位。印度块菌-云南松菌根际土壤细菌类群具有较高的多样性,物种种类丰富,优势菌群集中。

Study of bacterial population composition and structure of Tuber indicum×Pinus yunnanensis ectomycorrhizosphere

The bacterial diversity of the Tuber indicum×Pinus yunnanensis mycorrhizosphere was studied. The mycorrhizosphere in T. indicum×Pinus yunnanensis was collected in the field and the culturable bacteria were purified from the soil. The 16S rRNA genes of the purified bacteria were sequenced and a phylogenetic tree was constructed to analyze the population composition and structure of the culturable bacteria. Roche 454 high-throughput sequencing was used to determine the population composition and structure of all bacteria in the soil. (1) 793 culturable bacteria, representing 3 geni and 61 OTUs (Operational Taxonomic Units), were purified from the mycorrhizosphere. OTUs of the genus Pseudomonas accounted for 86% of the total OTUs, OTUs of the genus Acinetobacter accounted for 9.8% of the total OTUs, and OTUs of the genus Streptomyces accounted for 6.5% of the total OTUs. Pseudomonas was the predominant culturable bacteria in the mycorrhizosphere of T. indicum×Pinus yunnanensis. (2) 8937 sequences of the bacterial V1-V3 region, representing 2073 OTUs, were analyzed by using Roche 454 high-throughput sequencing. Proteobacteria, Actinobacteria, and Acidobacteria were the three dominant phylums, which accounted for 65.9% of the total OTUs. Flavobacterium, Rhizobium, and Pseudoxanthomona were the dominant geni, which accounted for 33% of the total OTUs. The population composition of culturable bacteria of T. indicum×P. yunnanensis mycorrhizosphere was simple; the dominant genus was Pseudomonas. The bacterial diversity of T. indicum×P. yunnanensis mycorrhizosphere was very high; the bacterial population was complex.