Plateau lakes are often pristine and less disturbed ecosystems. Studying the interactions among microbial diversity, resistance genes, and nitrogen metabolism processes in these environments can provide profound insights into natural processes. This study investigated eight typical Plateau lakes and explored the distribution patterns of microbial communities and functional diversity across different fractions (pore sizes). It was found that particle-attached (PA) fractions exhibited significantly higher community diversity, while free-living (FL) fractions showed significantly higher functional diversity. Multiresistance, macrolide-lincosamide-streptogramin (MLS), and tetracycline resistance genes are the predominant types of ARGs in Plateau lakes. Mobile genetic elements (MGEs) play a crucial role in the dissemination and risk transmission of resistance genes. A total of 64 potential hosts for antibiotic resistance genes (ARGs) were identified, with Limnohabitans, Aestuariivirga, and Stenotrophomonas being the primary carriers of ARGs in both fractions. Furthermore, it was discovered that the dissimilatory nitrate reduction to ammonium (DNRA) process dominates nitrogen metabolism in Plateau lakes, indicating a potential risk of nitrogen retention. The abundance of DNRA-related genes demonstrated a strong positive correlation with ARGs. Gammaproteobacteria were identified as the main hosts for the co-hosts of DNRA-related genes and ARGs. This research significantly contributes to understanding the ecological risks posed by the interaction between microbially-driven nitrogen metabolism and antibiotic resistance in less impacted Plateau lake ecosystems.

Hybridization has fascinated biologists in recent centuries for its evolutionary importance, especially in plants. Hybrid zones are commonly located in regions across environmental gradients due to more opportunities to contact and ecological heterogeneity. For aquatic taxa, intrazonal character makes broad overlapping regions in intermediate environments between related species. However, we have limited information on the hybridization pattern of aquatic taxa across an altitudinal gradient. In this study, we aimed to test the hypotheses that niche overlap and hybridization might be extensive in related aquatic plants in alpines. We evaluated the niche overlap in three related species pairs on the Qinghai-Tibetan Plateau and assessed the spatial pattern of hybrid populations. Obvious niche overlap and common hybridization were revealed in all three pairs of related aquatic plants. The plateau edge and river basins were broad areas for the sympatry of divergent taxa, where a large proportion of hybrid populations occurred. Hybrids are also discretely distributed in diverse habitats on the plateau. Differences in the extent of niche overlap, genetic incompatibility and phylogeographic history might lead to inconsistences in hybridization patterns among the three species pairs. Our results suggested that plateau areas are a hotspot for ecologically divergent aquatic species to contact and mate and implied that hybridization may be important for the freshwater biodiversity of highlands.