Rhizoremediation is a potential technique for polycyclic aromatic hydrocarbon (PAH) remediation; however, the catabolic pathways of in situ rhizosphere PAH degraders and the main factors driving PAH rhizoremediation remain unclear. To address these issues, stable-isotope-probing coupled with metagenomics and molecular ecological network analyses were first used to investigate the phenanthrene rhizoremediation by three different prairie grasses in this study. All rhizospheres exhibited a significant increase in phenanthrene removal and markedly modified the diversity of phenanthrene degraders by increasing their populations and interactions with other microbes. Of all the active phenanthrene degraders, Marinobacter and Enterobacteriaceae dominated in the bare and switchgrass rhizosphere respectively; Achromobacter was markedly enriched in ryegrass and tall fescue rhizospheres. Metagenomes of ¹³C-DNA illustrated several complete pathways of phenanthrene degradation for each rhizosphere, which clearly explained their unique rhizoremediation mechanisms. Additionally, propanoate and inositol phosphate of carbohydrates were identified as the dominant factors that drove PAH rhizoremediation by strengthening the ecological networks of soil microbial communities. This was verified by the results of rhizospheric and non-rhizospheric treatments supplemented with these two substances, further confirming their key roles in PAH removal and in situ PAH rhizoremediation. Our study offers novel insights into the mechanisms of in situ rhizoremediation at PAH-contaminated sites.

中文翻译：

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油污染土壤原位根际多环芳烃降解物的分解代谢途径及驱动多环芳烃根际修复的主要因素

根际修复是多环芳烃（PAH）修复的技术潜力；然而，原位根际 PAH 降解剂的分解代谢途径以及驱动 PAH 根际修复的主要因素仍不清楚。为了解决这些问题，本研究首先使用稳定同位素探测结合宏基因组学和分子生态网络分析来研究三种不同草原草的菲根际修复。所有根际都表现出对菲的去除显着增加，并通过增加其数量和与其他微生物的相互作用显着改变了菲降解物的多样性。在所有活性菲降解剂中，海杆菌属和肠杆菌科分别以裸露根际和柳枝稷根际为主；无色杆菌在黑麦草和高羊茅根际中显着富集。¹³ C-DNA的宏基因组说明了每个根际菲降解的几个完整途径，这清楚地解释了它们独特的根际修复机制。此外，通过加强土壤微生物群落的生态网络，碳水化合物的丙酸和磷酸肌醇被确定为推动 PAH 根际修复的主要因素。这通过补充这两种物质的根际和非根际处理的结果得到验证，进一步证实了它们在多环芳烃去除和原位处理中的关键作用PAH 根际修复。我们的研究为多环芳烃污染场地的原位根际修复机制提供了新的见解。