Sun H Y, Deng S P, Raun W R
Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078-6028, USA.
Appl Environ Microbiol. 2004 Oct;70(10):5868-74. doi: 10.1128/AEM.70.10.5868-5874.2004.
Changes in soil microbial community structure and diversity may reflect environmental impact. We examined 16S rRNA gene fingerprints of bacterial communities in six agroecosystems by PCR amplification and denaturing gradient gel electrophoresis (PCR-DGGE) separation. These soils were treated with manure for over a century or different fertilizers for over 70 years. Bacterial community structure and diversity were affected by soil management practices, as evidenced by changes in the PCR-DGGE banding patterns. Bacterial community structure in the manure-treated soil was more closely related to the structure in the untreated soil than that in soils treated with inorganic fertilizers. Lime treatment had little effect on bacterial community structure. Soils treated with P and N-P had bacterial community structures more closely related to each other than to those of soils given other treatments. Among the soils tested, a significantly higher number of bacterial ribotypes and a more even distribution of the bacterial community existed in the manure-treated soil. Of the 99 clones obtained from the soil treated with manure for over a century, two (both Pseudomonas spp.) exhibited 100% similarity to sequences in the GenBank database. Two of the clones were possible chimeras. Based on similarity matching, the remaining 97 clones formed six major clusters. Fifty-six out of 97 were assigned taxonomic units which grouped into five major taxa: alpha-, beta-, and gamma-Proteobacteria (36 clones), Acidobacteria (16 clones), Bacteroidetes (2 clones), Nitrospirae (1 clone), and Firmicutes (1 clone). Forty-one clones remained unclassified. Results from this study suggested that bacterial community structure was closely related to agroecosystem management practices conducted for over 70 years.
土壤微生物群落结构和多样性的变化可能反映环境影响。我们通过聚合酶链反应（PCR）扩增和变性梯度凝胶电泳（PCR-DGGE）分离技术，检测了六种农业生态系统中细菌群落的16S rRNA基因指纹。这些土壤施用粪肥已逾一个世纪，或施用不同肥料已逾70年。PCR-DGGE条带模式的变化表明，土壤管理措施影响了细菌群落结构和多样性。与无机肥料处理的土壤相比，施用粪肥的土壤中细菌群落结构与未处理土壤中的结构更为相似。石灰处理对细菌群落结构影响不大。施用磷肥和氮磷肥的土壤，其细菌群落结构彼此之间的相关性高于其他处理的土壤。在所测试的土壤中，施用粪肥的土壤中细菌核糖型数量显著更多，细菌群落分布也更为均匀。从施用粪肥逾一个世纪的土壤中获得的99个克隆中，有两个（均为假单胞菌属）与GenBank数据库中的序列显示100%的相似性。其中两个克隆可能是嵌合体。基于相似性匹配，其余97个克隆形成了六个主要聚类。97个克隆中有56个被指定为分类单元，分为五个主要类群：α-、β-和γ-变形菌门（36个克隆）、酸杆菌门（16个克隆）、拟杆菌门（2个克隆）、硝化螺旋菌门（1个克隆）和厚壁菌门（1个克隆）。41个克隆仍未分类。本研究结果表明，细菌群落结构与长达70多年的农业生态系统管理措施密切相关。
