摘要

       植物根部被土壤细菌定植，这些细菌是已知的抗生素抗性基因 (ARG) 的储存库。 ARGs 可以在这些微生物和病原体之间转移，但这些 ARGs 和病原体在多大程度上从土壤传播到植物中却知之甚少。在这里，我们使用扩增子和宏基因组测序检查了沿红树林树苗土壤-根系连续体的高分辨率抗性组谱。数据显示，总 ARG 的 91.4% 由四个与根相关的隔室（内圈、外圈、根际和未种植的土壤）共享。抵抗组不是微生物群的区室选择性动力学，而是沿着土壤 - 根系连续体以连续方式传播。这种传播与潜在的根相关细菌和真菌微生物群无关，但可能受到多种可移动遗传元件的促进。作为多重耐药病原体，创伤弧菌、致病性大肠杆菌和肺炎克雷伯菌在四个区室中始终占主导地位，表明抗生素病原体可能沿土壤-根系连续传播。通过破译根相关抗性组和病原体的概况和动态，我们的研究将土壤 - 根连续体确定为一个相互连接的汇，某些 ARG 和病原体可以通过它从土壤流入植物。

       Plants roots are colonised by soil bacteria that are known to be the reservoir of antibiotic resistance genes (ARGs). ARGs can transfer between these microorganisms and pathogens, but to what extent these ARGs and pathogens disseminate from soil into plant is poorly understood. Here, we examined a high-resolution resistome profile along the soil–root continuum of mangrove saplings using amplicon and metagenomic sequencing. Data revealed that 91.4% of total ARGs were shared across four root–associated compartments (endosphere, episphere, rhizosphere and unplanted soil). Rather than compartment-selective dynamics of microbiota, the resistome was disseminated in a continuous fashion along the soil–root continuum. Such dissemination was independent of underlying root–associated bacterial and fungal microbiota, but might be facilitated by a multiplicity of mobile genetic elements. As the multiple-drug resistant pathogens, Vibrio vulnificus, pathogenic Escherichia coli and Klebsiella pneumoniae consistently predominated across four compartments, indicating the potential dissemination of antibiotic pathogens along the soil–root continuum. Through deciphering the profile and dynamics of the root–associated resistome and pathogens, our study identified the soil–root continuum as an interconnected sink through which certain ARGs and pathogens can flow from soil into the plant.

https://www.sciencedirect.com/science/article/abs/pii/S0304389420329769