<b>Distinct root exudation patterns in emergent plants yield similar rhizosphere microbial communities</b>

Emergent plants with different root morphologies show considerable variation in their nitrogen removal capabilities via nitrification and denitrification processes; however, the underlying mechanisms are still unknown. This study investigates how root morphology influences root exudates and rhizosphere microbial communities in two emergent plant species: Zizania latifolia (taprooted) and Pontederia cordata (fibrous-rooted). Root exudates were collected and analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), revealing distinct metabolic profiles between the two species. Z. latifolia primarily secreted benzenoids, while P. cordata exuded higher levels of lipids and lipid-like molecules. Despite these differences, the rhizosphere bacterial and fungal communities of both plants were similar in both structures and potential functions. Interestingly, the differential metabolites identified in Z. latifolia root exudates, especially amino acids (e.g., denticetic acid and itopride), exhibited significant and positive correlations with denitrifying bacterial genera, such as Pseudomonas and Clostridium, suggesting that these metabolites may play a crucial role in the recruitment of specific microbial communities. These findings highlight the complex interactions between root exudates, rhizosphere microbes, and nitrogen cycling in emergent plants, providing insights for optimizing wetland restoration strategies.不同根系形态的挺水植物，通过硝化与反硝化过程实现的脱氮能力存在显著差异，但其背后的调控机制仍未明晰。本研究选取菰（Zizania latifolia，直根系）与梭鱼草（Pontederia cordata，须根系）两种挺水植物，探究根系形态如何调控根系分泌物与根际微生物群落。研究通过超高效液相色谱-串联质谱（UHPLC-MS/MS）收集并分析两类植物的根系分泌物，结果显示二者的代谢谱存在显著差异：菰主要分泌苯类化合物，而梭鱼草则释放更高水平的脂质及类脂质分子。尽管存在上述代谢差异，两种植物的根际细菌与真菌群落在群落结构及潜在功能上均较为相似。有趣的是，菰根系分泌物中鉴定出的差异代谢物——尤其是氨基酸类物质（如denticetic acid与itopride）——与假单胞菌属（Pseudomonas）、梭菌属（Clostridium）等反硝化细菌属呈现显著正相关，提示此类代谢物可能在特异性微生物群落的招募过程中发挥关键作用。本研究结果揭示了挺水植物根系分泌物、根际微生物与氮循环之间的复杂互作关系，为优化湿地修复策略提供了理论参考。