eDNA-based biomonitoring at an experimental German vineyard to characterize how management regimes shape ecosystem diversity

There is growing interest in the application of sustainable agricultural methods to minimize the environmental impact of farming and thus aiding quantification of the actual benefit that such approaches may confer. We applied DNA metabarcoding with the aim of exploring how the diversity of fungi and arthropods were affected by different agricultural management systems (integrated, organic, biodynamic) at the experimental vineyard of Geisenheim (Rheingau, Germany). Data were generated for the bloom and harvest periods in 2017, using environmental DNA (eDNA) metabarcoding analysis of both soil and vane trap samples. Our data revealed four principal results. (a) Overall richness of vane trap samples was unaffected by the management systems, likely due to the relatively small scale of the plots compared to the ranges of taxa such as the arthropods caught. In contrast, however, the richness of soil-living taxa appeared to be negatively affected by conventional treatments, especially at harvest. (b) Analysis of similarity revealed that the species composition was significantly differentiated by management systems for both fungal and other taxa in both sample types. (c) Taxonomic analysis of fungi revealed that the management system drove differentiation in the abundance patterns for wine-related fungi. Overall, our study reiterates the potential of eDNA techniques as a tool for assessing how biodiversity is affected by different agricultural management regimes, and we hope such approaches will be adopted in future research aimed at guiding vineyard management decisions

Insights into the circular: The cryptic plasmidome and its derived antibiotic resistome in the urban water systems

Plasmids have been a concern in the dissemination and evolution of antibiotic resistance in the environment. In this study, we investigated the total pool of plasmids (plasmidome) and its derived antibiotic resistance genes (ARGs) in different compartments of urban water systems (UWSs) in three European countries representing different antibiotic usage regimes. We applied a direct plasmidome approach using wet-lab methods to enrich circular DNA in the samples, followed by shotgun sequencing and in silico contig circularisation. We identified 9538 novel sequences in a total of 10,942 recovered circular plasmids. Of these, 66 were identified as conjugative, 1896 mobilisable and 8970 non-mobilisable plasmids. The UWSs’ plasmidome was dominated by small plasmids (≤10 Kbp) representing a broad diversity of mobility (MOB) types and incompatibility (Inc) groups. A shared collection of plasmids from different countries was detected in all treatment compartments, and plasmids could be source-tracked in the UWSs. More than half of the ARGs-encoding plasmids carried mobility genes for mobilisation/conjugation. The richness and abundance of ARGs-encoding plasmids generally decreased with the flow, while we observed that non-mobilisable ARGs-harbouring plasmids maintained their abundance in the Spanish wastewater treatment plant. Overall, our work unravels that the UWS plasmidome is dominated by cryptic (i.e., non-mobilisable, non-typeable and previously unknown) plasmids. Considering that some of these plasmids carried ARGs, were prevalent across three countries and could persist throughout the UWSs compartments, these results should alarm and call for attention