摘要

    污泥堆肥经常被用作农作物的肥料，尽管它可能富含抗生素抗性基因（ARG）和无法通过堆肥去除的重金属。缺乏对影响ARGs传播至用污泥产品处理过的土壤中种植的蔬菜的因素的深入了解。在这项研究中，评估了重金属胁迫（即Cd）下青葱的块茎和根际土壤和内生植物中的目标ARGs，并确定了导致ARGs传播的因素。镉胁迫导致块状和根际土壤及内生菌中目标ARG的相对丰度增加。在不同程度的镉胁迫下，土壤和植物中的驱动因子是不同的。真菌群落组成是块状和根际土壤中ARG变化的主要驱动因素。此外，内生细菌在将ARGs转移至植物中起着至关重要的作用。较高的Cd胁迫促进了大多数目标ARGs从地下植物部分转移到地面以上部分。这些发现表明，施用被镉等重金属污染的污泥可以促进ARGs在蔬菜中的传播，在评估对公共健康的风险时必须考虑到这一点。

    Sludge compost is often used as a fertilizer for crops, although it might be enriched with antibiotic resistance genes (ARGs) and heavy metals that cannot be removed through composting. A robust understanding of the factors affecting the transmission of ARGs to vegetables grown in soils treated with sludge products is lacking. In this study, target ARGs in the bulk and rhizosphere soils and endophytes of shallots under heavy metal stress (i.e., Cd) were assessed, and the factors driving the transmission of ARGs were identified. Cd stress resulted in an increase in the relative abundances of target ARGs in the bulk and rhizosphere soils and endophytes. The driving factors were different in soils and plants under different degrees of Cd stress. The fungal community composition was the main driving factor of ARG variation in both bulk and rhizosphere soils. Moreover, endophytic bacteria played a crucial role in transferring ARGs to plants. Higher Cd stress promoted the transfer of most target ARGs from the below-ground plant parts to the above-ground parts. These findings indicate that application of sludge contaminated with heavy metals, such as Cd, can facilitate the dissemination of ARGs into vegetables, which must be considered while assessing the risks to public health.

    https://www.sciencedirect.com/science/article/abs/pii/S0048969720325079