微界面尺度下四溴双酚A驱动土壤微生物群落演替及其迁移与代谢机制

Microinterface-scale insights into TBBPA-induced microbial community succession and its coupled migration-metabolism mechanisms in soil

摘要:

四溴双酚A(tetrabromobisphenol A, TBBPA)作为广泛存在的新污染物，其在土壤中的微生物胁迫响应与代谢过程主要发生于微界面处。本研究通过构建毫米尺度的微界面土壤系统，旨在系统揭示TBBPA在微界面的迁移及其对土壤微生物群落与代谢的驱动机制。结果表明TBBPA因强疏水性显著富集于表层0?10 mm区域，通过改变土壤微结构(孔隙增多/团聚体松散)重塑微生物生态位，导致细菌群落的α多样性在污染热点区骤降(Ace/Chao指数>42%)，其中甲基弯曲菌属(Methylotenera)变化最大。TBBPA驱动空间梯度演替——近源区富集耐受/脱卤菌(Micromonospora/Bacillus)，远源区演替为开环/矿化菌(Pseudomonas/Methylotenera)。共现网络分析揭示纵向梯度形成高度协同网络(正相关边>89%)，横向异质环境则呈现高模块化结构(模块度0.552)。代谢组学显示TBBPA诱导了细胞膜磷脂、芳香族化合物代谢物与螯合剂等关键代谢产物显著上调，同时抑制了部分硫代谢和信号相关小分子的合成。此外代谢产物中检测到脱溴、开环、β-氧化三阶段关键中间体，证实多酶系串联的降解通路，该过程伴随牺牲硫循环的代谢重编程。本研究从土壤修复角度揭示了微界面尺度的微生物-污染物互作机制，为优化菌群与界面改性、提升TBBPA及类似疏水有机污染物的靶向降解提供理论支撑。

Abstract:

Tetrabromobisphenol A (TBBPA), a widely distributed emerging contaminant, exerts stress on microorganisms and undergoes transformation primarily at microinterface regions within soil environments. To systematically elucidate TBBPA migration at the millimeter-scale microinterface and its driving effects on soil microbial communities and metabolic pathways, a millimeter-scale microinterface soil system was constructed and subjected to spatially resolved multi-omics analyses. Results revealed that owing to its pronounced hydrophobicity, TBBPA was strongly enriched within the 0-10 mm surface horizon. By increasing pore abundance and loosening soil aggregates, TBBPA restructured the soil microarchitecture and reshaped microbial ecological niches, leading to a marked decline in α-diversity of bacterial communities within contamination hotspots (decreasing Ace/Chao indices by >42%), with Methylotenera exhibiting the most pronounced shift. Furthermore, TBBPA drove a clear spatial successional gradient: proximal zones were enriched with tolerant and dehalogenating taxa (Micromonospora and Bacillus), whereas distal zones were enriched with ring-cleaving and mineralizing assemblages (Pseudomonas and Methylotenera). Co-occurrence network analysis revealed strong microbial synergism along the vertical axis, characterized by a high proportion of positive correlations (>89%). In contrast, lateral heterogeneity promoted the formation of a compartmentalized network architecture with high modularity (modularity=0.552), which indicated functional differentiation across microenvironments. Metabolomic profiling unveiled a substantial upregulation of key metabolic signatures, including membrane phospholipids, aromatic intermediates, and metal-chelating compounds, in response to TBBPA exposure, alongside a concurrent downregulation of sulfur-related metabolites and signaling molecules. Notably, critical intermediates associated with debromination, ring-opening, and β-oxidation were identified, confirming a multi-enzymatic, stepwise catabolic pathway. This degradation cascade was coupled with the reprogramming of sulfur metabolism, suggesting a metabolic trade-off strategy adopted by soil microbiota during TBBPA detoxification. This study, from a soil remediation perspective, elucidates the microinterface-scale interactions between microorganisms and pollutants, providing a theoretical basis for optimizing microbial consortia and interfacial modifications to enhance the targeted degradation of TBBPA and other hydrophobic organic contaminants.