Spatiotemporal dynamics of multi-kingdom microbiome interactions drive CNPS cycling in landfills.

Landfill ecosystems represent significant terrestrial carbon sinks, where municipal solid waste (MSW) undergoes decomposition and transformation through biochemical reactions mediated by multi-kingdom microbiome. However, the spatial and temporal characterization of microbial interactions and collaboration within these multi-kingdom microbiomes remain largely unknown. In this study, we reveal the hierarchical and collaborative mechanisms by which multi-kingdom microbiomes drive carbon, nitrogen, phosphorus, and sulfur cycling across a 30-meter landfilling depth, corresponding to a landfilling age of 1 to 4 years. Through integration of metagenomics and network analyses, we elucidated vertical succession patterns in microbial community structure and function. The surface layer (1-2 years) was centered on bacterial-dominated primary metabolism, with Enterococcus aquimarinus and Brevundimonas bullata inferred to mediate metabolic coupling through fermentation, nitrogen fixation andphosphorus solubilization. Concurrently, phage-driven host lysis may contribute to the suppression of acidification. In the middle layer (2-3 years), co-occurrence patterns between archaea and fungi suggest mutualistic interaction supporting methanogenesis, wherein fungi such as Anaeromyces robustus would supply key substrates for methanogens such as Methanofollis ethanolicus. In the bottom layer (3-4 years), fungi, bacteria, and viruses collaborate under nutrient-limited conditions, with phages employing a "kill-the-winner" approach to sustain ecosystem function and stability. Collectively, our findings indicate that key microbial connectors across kingdoms contribute to elemental cycling through cross-kingdom interaction, including substrate exchange and nutrient supply. This study advances our understanding of multi-kingdom microbial dynamics during MSW decomposition and offers a conceptual framework for enhancing biogeochemical cycling efficiency within landfill ecosystems.