Rhizospheric phosphorus activation drives microbial degradation of tris(2-chloroethyl) phosphate

Organophosphate esters (OPEs), such as tris(2-chloroethyl) phosphate (TCEP), undergo accelerated microbial degradation in the rhizosphere, but underlying mechanisms remain unclear. Given their structural similarity to natural organophosphorus compounds, we hypothesized that rhizospheric phosphorus cycling contributes to OPE degradation. Using DNA-stable isotope probing, we identified active TCEP degraders and linked them to soil phosphate fractions. Plant cultivation reshaped degrader communities, increasing their relative abundance by 80.7% and predicted functional gene content by 20.8%, while reducing interactions between degraders and non-degraders. Rhizospheric TCEP degraders exhibited a lower average phylogenetic distance than those in non-rhizosphere soils (0.58 vs. 0.64). This contrasts with the greater phylogenetic breadth observed for rhizospheric PAH and PCB degraders. The reduced phylogenetic breadth suggests that TCEP degradation may be more functionally conserved and dominated by specialized taxa, potentially reflecting phosphatase-mediated processes rather than cooperative, multi-taxon degradation networks. TCEP degradation correlated negatively with total phosphorus but positively with bioavailable phosphorus, indicating a key role of plant-mediated phosphorus solubilization in regulating degrader composition and activity. Increased alkaline phosphatase activity further supported this interpretation. Collectively, these findings reveal a previously unrecognized mechanism by which rhizospheric nutrient cycling regulates TCEP degradation, advancing our understanding of phosphorus-microbe interactions in pollutant biotransformation within plant-soil systems. SYNOPSIS: Plant-mediated phosphorus cycling in the rhizosphere selectively enriches TCEP-degrading microbes, uncovering a novel link between nutrient availability and pollutant biotransformation in soil ecosystems.