Resistance Gene Dynamics, Biogeochemical Coupling, and Ecological Risks in Sediments of Anthropogenically Impacted Lake Wetlands in China

Antibiotic resistance is a growing global threat to both
public
health and ecosystem stability. While the “One Health”
framework emphasizes the need to monitor antibiotic resistance genes
(ARGs) across diverse environments worldwide, the risks posed by ARGs
in lakes affected by human activities, particularly in lake sediments
that serve as natural reservoirs of ARGs, remain poorly understood.
Metagenomics enables culture-independent analysis of microbial communities
and resistance genes, providing essential insights into ARG dynamics.
This study investigates microbial communities, ARGs, metal resistance
genes (MRGs), and mobile genetic elements (MGEs) in sediments from
Lake Donghu and Lake Weishan in China, two contrasting lake ecosystems
subject to urbanization and agricultural activities for over four
decades, using high-throughput metagenomic sequencing and assembly.
ARGs and MRGs were more strongly influenced by deterministic environmental
factors, particularly heavy metals (Cd, Pb, Cu), whereas microbial
community structures were predominantly shaped by stochastic processes.
Metagenomic binning yielded 293 metagenome-assembled genomes (MAGs),
125 of which were identified as potential ARG hosts, with Proteobacteria
and Desulfobacterota being the most common. These hosts frequently
cocarried MGEs, virulence factor genes (VFGs), and MRGs and exhibited
metabolic pathways linked to carbon, nitrogen, and greenhouse gas
(CO2 and N2O) cycling. Dissolved organic carbon
(DOC) was determined as a key factor influencing microbial metabolism
and promoting resistance gene dissemination. Our findings highlight
a tight coupling between ARG dissemination, microbial ecological functions,
and biogeochemical processes, underscoring ecosystem-level risks associated
with resistance proliferation in human-impacted wetlands of China
and elsewhere.