Department of Genetics and Evolution, University of Białystok, Białystok, Poland.
Curr Microbiol. 2013 May;66(5):493-8. doi: 10.1007/s00284-013-0303-z. Epub 2013 Jan 16.
The aim of this study was to identify heavy metal detoxification system in Rhizobium leguminosarum bv. trifolii isolated from Trifolium repens inhabiting old (70-100 years) Zn-Pb waste heaps in Poland by PCR reaction with czcD1 and czcD2 primers. By sequence analysis, four different genotypes of obtained amplicons were identified among eight examined isolates. Their sequence similarity ranged 91-99 %. They indicated the highest sequence identity to the hypothetical lysine exporter gene of R. leguminosarum bv. trifolii WSM1325 (91-97 %) and 76-81 % sequence similarity to hypothetical lysine exporter genes of R. leguminosarum bv. trifolii WSM2304 and R. etli CFN42 and CIAT652. On phylogenetic tree of obtained amplicons, all four studied R. leguminosarum bv. trifolii genotypes formed common monophyletic cluster with R. leguminosarum bv. trifolii WSM1325 at 100 % bootstrap support showing that all four amplicons obtained in PCR with czcD1 and czcD2 primers are fragments of hypothetical lysine exporter gene (lysE). We also suggest that Lys efflux exporter may participate in heavy metal transport out of R. leguminosarum bv. trifolii cells.
本研究旨在通过 PCR 反应与 czcD1 和 czcD2 引物，从波兰旧（70-100 年）Zn-Pb 废料堆中栖息的三叶草根瘤菌（Rhizobium leguminosarum bv. trifolii）中鉴定重金属解毒系统。通过序列分析，在 8 个被检测的分离物中，获得了 4 种不同基因型的扩增子。它们的序列相似性在 91-99%之间。它们与三叶草根瘤菌 WSM1325 的假定赖氨酸外排基因具有最高的序列同一性（91-97%），与三叶草根瘤菌 WSM2304 和 R. etli CFN42 和 CIAT652 的假定赖氨酸外排基因具有 76-81%的序列相似性。在所获得的扩增子的系统发育树上，所有 4 种研究的三叶草根瘤菌 bv. trifolii 基因型均与三叶草根瘤菌 WSM1325 形成共同的单系聚类，支持率为 100%，表明在 PCR 中用 czcD1 和 czcD2 引物获得的所有 4 个扩增子均为假定赖氨酸外排基因（lysE）的片段。我们还提出，Lys 外排外排可能参与重金属从三叶草根瘤菌 bv. trifolii 细胞中的运输。
