Host-driven microbiome assembly supports nitrogen removal by macrophytes under chronic environmental stress (PRJCA044286)

Submerged macrophytes are vital for aquatic ecosystem stability and are widely used in ecological restoration, yet the mechanism and quantitative role of plant-microbiome interactions in nitrogen (N) removal under chronic N stress caused by untreated sewage remains poorly understood. Here, we integrated host transcriptomics, untargeted GC-MS metabolomics, and micro-spatial 16S rRNA sequencing to decipher the Vallisneria natans-microbiome interplay under chronic N exposure (8 mg/L). We demonstrated that N-stressed V. natans strategically reshaped its exudate profile (upregulating purines and coumarins) to recruit multifunctional plant growth-promoting rhizobacteria (PGPR), e.g. Pseudomonas and Acinetobacter, in inner biofilms. This exudate-guided assembly created a mutually beneficial loop: PGPR enhanced host stress tolerance while gaining preferential carbon access, collectively driving a 34.4% N removal efficiency at 50% of system N removal to this plant-microbiome priming effect--providing the first empirical evidence of its dominant role. Our study establishes three key advances: (1) revealing an active, optimally adaptive plant mechanism under N stress via targeted exudate-microbiome reprogramming; (2) establishing a predictive framework linking plant stress responses to microbial N removal; and (3) validating submerged macrophytes as a scalable nature-based solution for eutrophication control.