【摘要】 对黄土高原西峰地区黄土沉积物中的有机质进行了总DNA提取和PCR(聚合酶链式反应)扩增,通过克隆测序技术构建了含有44个克隆子的细菌16SrDNA文库。对16SrDNA系统发育的分析表明,西峰地区的黄土沉积物中细菌可分属13个类群,包括:酸杆菌(Acidobacteria)、变形菌(Proteobacteria)、放线菌(Actinobacteria)、绿弯菌(Chloroflexi)、厚壁菌(Firmicutes)、疣微菌(Verrucomicrobia)、浮霉菌(Planctomycetes)、芽单胞菌(Gemmatimonadetes)、异常球菌—栖热菌(Deinococcus-Thermus)、硝化螺旋菌(Nitrospirae)、蓝细菌(Cyanobacteria)、拟杆菌(Bacteroidetes)和Candidate division TG1。其中酸杆菌为最主要优势类群,变形菌为次优势类群,二者占黄土细菌总克隆数的70%,且大多为不可培养的基因型。更多还原

【Abstract】 The development of culture-independent techniques using nucleic acids has provided much new insight into studies of microbial diversity of soils. In this study, the bulk DNA was extracted and purified from the loess deposit in the Xifeng Section, the northwest of China, and subjected to PCR amplification with primers specific for 16S rRNA gene sequences (rDNAs). Then a 16S rDNA clone library was constructed and 44 clones were sequenced. Phylogenetic analysis of these sequences revealed extensive diversity. Guided by the phylogenetic tree, bacteria fell into 13 main lineages: Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, Firmicutes, Verrucomicrobia, Planctomycetes, Gemmatimonadetes, Deinococcus-Thermus, Nitrospirae, Cyanobacteria, Bacteroidetes and Candidate division TG1. It is striking to find that the Acidobacteria division was the most abundant phylogenetic group in loess, occupying 43.3% of total clones. Acidobacteria group includes 17 gene types and 65 clones, most of which are uncultured type. The Proteobacteria division (26.7%) was the second-predominant bacterial community, including 13 gene types and 40 clones. These two divisions (accounting for 70% of clones) represented the majority of the identified phylotypes in loess. However, further study is needed to probe into the function and environmental implications for the two predominant bacterial communities in loess.更多还原