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运用PCR-RFLP技术,对桂西北喀斯特原生土壤和退化生态系统土壤细菌16S rDNA基因多样性及系统发育关系进行了研究.结果表明:原生土壤比退化生态系统土壤具有更丰富的16S rDNA基因型和更高的多样性指数,两样地共有的基因型仅有2个.从每种基因型中随机选择一个克隆子作为代表进行测序分析,所有序列与GenBank数据库中序列的同源性为87%～100%,且两样地中均有超过一半的基因型序列与数据库中已知序列同源性低于97%,属于分类在“种”地位上的新发现细菌;通过系统发育研究将两样地的细菌分为10大类群,两样地共同拥有5大类群,但两样地的细菌优势类群明显不同,原生土壤为Proteobacteria,含39种基因型,占总克隆子数的58.0%,退化生态系统土壤为Acidobacteria和Proteobacteria,分别含19种和15种基因型,占总克隆子数的32.5%和30.5%;与原生土壤细菌类群相比,退化生态系统土壤Proteobacteria类群明显减少,Acidobacteria类群明显增加.土壤理化性质及土壤环境因素的差异是引起两类型土壤细菌多样性差异的原因.
The 16S rDNA gene diversity and phylogeny of soil bacteria in primary and degraded ecosystems of karst areas of northwestern Guangxi were studied using PCR-RFLP technique.The results showed that the 16S rDNA genotypes of 16S rDNAs were more abundant in native soils than degraded soils, Higher diversity index, the two shared a total of only two genotypes from each genotype randomly selected as a representative of the cloned sequencing analysis, all sequences and GenBank database sequence homology was 87% ~ 100%, and more than half of both genotypes have a homology of less than 97% with known sequences in the database, belonging to newly discovered bacteria classified in the “species” status. Two species The bacteria were divided into 10 groups and shared 5 groups in both groups. However, the dominant groups of bacteria were significantly different in the two groups. The native soil was Proteobacteria with 39 genotypes, accounting for 58.0% of the total clones. The degraded ecosystems The soil was Acidobacteria and Proteobacteria, which contained 19 and 15 genotypes respectively, accounting for 32.5% and 30.5% of the total number of clones. Compared with the native soil bacterial groups, the contents of Proteobacteria teria taxa and the Acidobacteria taxa significantly increased.The differences of soil physical and chemical properties and soil environmental factors were the causes of the differences in bacterial diversity between the two types of soils.