Centre de Biotechnologies végétales et microbiennes, Biodiversité et Environnement, Faculty of Sciences, Mohammed V University, 4 Avenue Ibn Battouta, Agdal, Rabat, Morocco.
Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), E-419, 18080, Granada, Spain.
Braz J Microbiol. 2021 Jun;52(2):639-649. doi: 10.1007/s42770-021-00420-7. Epub 2021 Jan 14.
The aim of this work was to characterize and identify some bacteria isolated from the root nodules of Retama monosperma grown in Sidi Boubker lead and zinc mine tailings. Very few root nodules were obtained on the root nodules of R. monosperma grown in these soils. The three bacteria isolated from the root nodules were tolerant in vitro to different concentrations of heavy metals, including lead and zinc. The rep-PCR experiments showed that the three isolates have different molecular fingerprints and were considered as three different strains. The analysis of their 16S rRNA gene sequences proved their affiliation to the genus Bradyrhizobium. The analysis and phylogeny of the housekeeping genes atpD, glnII, gyrB, recA, and rpoB confirmed that the closest species was B. valentinum with similarity percentages of 95.61 to 95.82%. The three isolates recovered from the root nodules were slow-growing rhizobia capable to renodulate their original host plant in the presence of Pb-acetate. They were able to nodulate R. sphaerocarpa and Lupinus luteus also but not Glycine max or Phaseolus vulgaris. The phylogeny of the nodA and nodC nodulation genes as well as the nifH gene of the three strains showed that they belong to the symbiovar retamae of the genus Bradyrhizobium. The three strains isolated could be considered for use as inoculum for Retama plants before use in phytoremediation experiments.
这项工作的目的是对从生长在西迪布布克铅锌矿尾矿中的 Retama monosperma 根瘤中分离出的一些细菌进行特征描述和鉴定。在这些土壤中生长的 R. monosperma 的根瘤上获得的根瘤很少。从根瘤中分离出的三种细菌在体外对不同浓度的重金属，包括铅和锌具有耐受性。rep-PCR 实验表明，这三种分离株具有不同的分子指纹图谱，被认为是三种不同的菌株。对其 16S rRNA 基因序列的分析证明它们与 Bradyrhizobium 属有关。atpD、glnII、gyrB、recA 和 rpoB 看家基因的分析和系统发育表明，最接近的物种是 B. valentinum，相似度为 95.61%至 95.82%。从根瘤中回收的三种分离株是生长缓慢的根瘤菌，能够在存在 Pb-醋酸盐的情况下重新调节其原始宿主植物。它们还能够结瘤 R. sphaerocarpa 和 Lupinus luteus，但不能结瘤 Glycine max 或 Phaseolus vulgaris。三种菌株的 nodA 和 nodC 结瘤基因以及 nifH 基因的系统发育表明它们属于 Bradyrhizobium 属的 symbiovar retamae。分离出的三种菌株可考虑在用于植物修复实验之前用作 Retama 植物的接种物。
