Phytoremediation is a prevalent strategy to treat environmental pollution caused by heavy metals and eutrophication-related pollutants. Although rhizosphere microbiome is critical for phytoremediation, it remains a great challenge to artificially remodel rhizosphere microbiome for enhancing multiple pollutant treatment. In this study, we designed a synthetic bacterium to strengthen physical contact between natural microbes and plant roots for remodeling the Eichhornia crassipes rhizosphere microbiome during phytoremediation. The synthetic bacterium EcCMC was constructed by introducing a surface-displayed synthetic protein CMC composed of two glucan-binding domains separated by the sequence of the fluorescent protein mCherry. This synthetic bacterium strongly bound glucans and recruited natural glucan-producing bacterial and fungal cells. Microbiome and metabolomic analysis revealed that EcCMC remarkably remodeled rhizosphere microbiome and increased stress response-related metabolites, leading to the increased activity of antioxidant enzymes involved in stress resistance. The remodeled microbiome further promoted plant growth, and enhanced accumulation of multiple pollutants into the plants, with the removal efficiency of the heavy metal cadmium, total organic matters, total nitrogen, total potassium, and total phosphorus reaching up to 98%, 80%, 97%, 93%, and 90%, respectively. This study sheds a novel light on remodeling of rhizosphere microbiome for enhanced phytoremediation of water and soil systems.

植物修复是治理重金属和富营养化相关污染物造成的环境污染的一种普遍策略。尽管根际微生物组对于植物修复至关重要，但人工改造根际微生物组以增强多种污染物的处理仍然是一个巨大的挑战。在这项研究中，我们设计了一种合成细菌来加强天然微生物和植物根部之间的物理接触，从而重塑凤眼莲植物修复过程中的根际微生物组。合成细菌 EcCMC 是通过引入由荧光蛋白 mCherry 序列分隔的两个葡聚糖结合域组成的表面展示合成蛋白 CMC 构建的。这种合成细菌强烈结合葡聚糖并招募天然产生葡聚糖的细菌和真菌细胞。微生物组和代谢组学分析表明，EcCMC 显着重塑了根际微生物组并增加了与应激反应相关的代谢物，导致参与抗应激的抗氧化酶的活性增加。改造后的微生物组进一步促进植物生长，促进多种污染物在植物体内的积累，对重金属镉、总有机物、总氮、总钾、总磷分别达到98%、80%、97%、93%和90%。这项研究为重塑根际微生物组以增强水和土壤系统的植物修复提供了新的思路。