For a metal hyperaccumulator plant Sedum alfredii, the recruitment of unique rhizospheric bacterial communities from bulk soils has been well studied. However, in the root-soil interface, the knowledge on the establishment of endospheric microbiomes from rhizospheric soil is still scarce. In this study, we combined culture-independent that was 16S rRNA gene amplicon sequencing, and culture-dependent methods that included bacterial isolation, heavy metal tolerance and plant growth-promoting traits. The Cd/Zn concentrations in endosphere were significantly higher than in soil, while Pb concentration in endosphere was significantly lower than in soil. The α-diversity in rhizosphere soils was higher than in root endosphere, and the compartments as a major determinant revealed 85.9% of the taxa variations. The relative abundance of Proteobacteria increased in endosphere compared to rhizosphere. The difference of Cd/Zn tolerance between endospheric and rhizospheric isolates was not obvious, while the Pb tolerance of endospheric isolates significantly decreased compared to rhizosphere. The results suggest that S. alfredii recruits Cd/Zn-tolerant but not Pb-tolerant endospheric bacterial communities from its rhizospheric soil. The difference in the microbial structure and function in the root-soil interface might be related to the selective absorption of metals in S. alfredii.

中文翻译：

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超富集植物景天从其根际土壤中招募耐镉/锌但不耐铅的内层细菌群落

对于金属超富集植物景天，已经充分研究了从大块土壤中招募独特的根际细菌群落。然而，在根-土壤界面，从根际土壤中建立内层微生物群落的知识仍然很少。在这项研究中，我们结合了不依赖培养的 16S rRNA 基因扩增子测序和依赖培养的方法，包括细菌分离、重金属耐受性和促进植物生长的性状。内圈中的 Cd/Zn 浓度显着高于土壤中，而内圈中的 Pb 浓度显着低于土壤中。根际土壤中的 α 多样性高于根内圈，作为主要决定因素的区室揭示了 85.9% 的类群变异。与根际相比，内圈中变形菌的相对丰度增加。内圈和根际分离株对Cd/Zn的耐受性差异不明显，而内圈分离株的Pb耐受性较根际显着降低。结果表明，S. alfredii 从其根际土壤中招募耐镉/锌但不耐铅的内层细菌群落。根-土界面微生物结构和功能的差异可能与 S. alfredii 对金属的选择性吸收有关。alfredii 从其根际土壤中招募耐镉/锌但不耐铅的内层细菌群落。根-土界面微生物结构和功能的差异可能与 S. alfredii 对金属的选择性吸收有关。alfredii 从其根际土壤中招募耐镉/锌但不耐铅的内层细菌群落。根-土界面微生物结构和功能的差异可能与 S. alfredii 对金属的选择性吸收有关。