Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
J Microbiol Biotechnol. 2010 May;20(5):862-70. doi: 10.4014/jmb.0910.10012.
Cyperus rotundus L. is a perennial herb which was found prevailing in an area in the northeast of Brazil previously contaminated with petroleum. In order to enlarge the knowledge of microorganism-plant interaction in phytoremediation, the bacterial community present in the rhizosphere and roots of C. rotundus was evaluated by culture-dependent and molecular approaches. PCR-DGGE analyses based on the 16S rRNA gene showed that the profiles of bulk soil, rhizosphere and root samples had a high degree of similarity. A complex community of alkane utilizing-bacteria and a variable nitrogen-fixing community were observed when the PCR-DGGE analyses were based on the genes alkB and nifH, respectively. In addition, two clone libraries were generated from the alkB fragments of bulk and rhizosphere soils. Statistical analyses showed that the libraries were different concerning the alkB population composition. Using culture-dependent techniques, 209 bacterial strains were isolated from the rhizosphere and rhizoplane/roots of C. rotundus. Dot blotting analysis showed that the DNA from 17 strains hybridized, simultaneously, with the alkB and nifH probes. After partial 16S rRNA gene sequencing, these strains were affiliated with the genera Bosea, Cupriavidus, Enterobacter, Gordonia, Mycoplana, Pandoraea, Pseudomonas, Rhizobium and Rhodococcus. They can be considered of great potential for phytoremediation in this tropical soil area.
圆叶节节菜是一种多年生草本植物，生长在巴西东北部的一个曾受石油污染的地区。为了扩大植物修复中微生物-植物相互作用的知识，采用培养依赖和分子方法评估了圆叶节节菜根际和根部的细菌群落。基于 16S rRNA 基因的 PCR-DGGE 分析表明，原状土壤、根际和根样本的图谱具有高度的相似性。当基于 alkB 和 nifH 基因进行 PCR-DGGE 分析时，观察到了复杂的烷烃利用细菌群落和可变的固氮群落。此外，还从原状和根际土壤的 alkB 片段生成了两个克隆文库。统计分析表明，文库在 alkB 种群组成上存在差异。使用培养依赖的技术，从圆叶节节菜的根际和根面/根部分离出 209 株细菌。斑点杂交分析表明，17 株菌株的 DNA 与 alkB 和 nifH 探针同时杂交。经过部分 16S rRNA 基因测序，这些菌株与 Bosea、Cupriavidus、Enterobacter、Gordonia、Mycoplana、Pandoraea、Pseudomonas、Rhizobium 和 Rhodococcus 属有关。它们被认为在这个热带土壤地区具有很大的植物修复潜力。
