Artificial light at night triggers negative impacts on nutrients cycling and plant health regulated by soil microbiome in urban ecosystems

[Display omitted] •Artificial light at night (ALAN) disturbed microbial structure of urban soils.•ALAN increased the fungal phylogenetic diversity in urban soils.•ALAN declined the abundances of functional genes involved in nutrient cycling.•ALAN potentially increased the richness of phytopathogenic fungi in urban soils. Artificial light at night (ALAN) is a hallmark anthropogenic disturbance to urban ecosystems in the Anthropocene. However, the potential effects of ALAN on urban soil microbial community structure and functions are unclear yet. Here we combined amplicon sequencing and high-throughput qPCR to catalog the structure and functions of microbiomes in urban turf soils subjected to varying levels of nocturnal light. Our results showed that ALAN was an important factor influencing the structures of bacterial, fungal, and protist communities in urban soils. Moreover, ALAN potentially changed the microbial functional profiles involved in nutrients cycling and urban health. Specifically, nocturnal light significantly reduced the relative abundances of key functional genes involved in methanotrophic and denitrifying pathways in bacteria, including mmoX, mxa, nirK and nosZ. Further, ALAN exposure may marginally influence the abundances of fungal phytopathogen, which could increase odds of adverse effects on plant health in urban green spaces. Our findings highlight the significant effects of ALAN for soil bacterial and fungal communities, nutrient cycling and urban plant health. Moreover, our results suggest that vanishing darkness due to the expanded artificial illumination are likely to have long-term consequences for soil microbiomes and ecological functioning in urban ecosystems.