School of Ecology and Environment, Northwestern Polytechnical University, 1 Dongxiang Road, Chang'an District, Xi'an Shaanxi,710129, P.R. China.
Section for Microbial Ecology and Biotechnology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
FEMS Microbiol Ecol. 2020 Oct 20;96(11). doi: 10.1093/femsec/fiaa200.
Stressors like metals or antibiotics can affect bacterial community permissiveness for plasmid uptake, but there is little knowledge about long-term effects of such stressors on the evolution of community permissiveness. We assessed the effect of more than 90 years of soil Cu contamination on bacterial community permissiveness (i.e. uptake ability) toward a gfp-tagged IncP-1 plasmid (pKJK5) introduced via an Escherichia coli donor. Plasmid transfer events from the donor to the recipient soil bacterial community were quantified and transconjugants were subsequently isolated by fluorescence activated cell sorting and identified by 16S rRNA gene amplicon sequencing. Transfer frequency of plasmid pKJK5 was reduced in bacterial communities extracted from highly Cu contaminated (4526 mg kg-1) soil compared to corresponding communities extracted from moderately (458 mg kg-1) Cu contaminated soil and a low Cu reference soil (15 mg kg-1). The taxonomic composition of the transconjugal pools showed remarkable similarities irrespective of the degree of soil Cu contamination and despite contrasting compositions of the extracted recipient communities and the original soil communities. Permissiveness assessed at the level of individual operational taxonomic units (OTUs; 16S rRNA gene 97% sequence similarity threshold) was only slightly affected by soil Cu level and high replicate variability of OTU-level permissiveness indicated a role of stochastic events in IncP-1 plasmid transfer or strain-to-strain permissiveness variability.
压力源如金属或抗生素会影响细菌群落对质粒摄取的宽容度，但对于这些压力源对群落宽容度进化的长期影响知之甚少。我们评估了超过 90 年的土壤铜污染对细菌群落宽容度（即摄取能力）的影响，方法是通过大肠杆菌供体引入 GFP 标记的 IncP-1 质粒 (pKJK5)。通过荧光激活细胞分选分离和 16S rRNA 基因扩增子测序鉴定从供体到受体土壤细菌群落的质粒转移事件，并对其进行定量。与从中度（458 mg kg-1）铜污染土壤和低铜参考土壤（15 mg kg-1）中提取的相应群落相比，从高度铜污染（4526 mg kg-1）土壤中提取的细菌群落中，质粒 pKJK5 的转移频率降低。尽管提取的受体群落和原始土壤群落的组成存在差异，但转导池的分类组成显示出惊人的相似性，无论土壤铜污染程度如何。在个体分类操作单元（OTU；16S rRNA 基因 97%序列相似性阈值）水平评估的宽容度仅受到土壤铜水平的轻微影响，并且 OTU 水平宽容度的高重复可变性表明随机事件在 IncP-1 质粒转移或菌株间宽容度变异性中起作用。
