Responses of microbial communities during oilseed plant-based phytoremediation of heavy metal-contaminated soils.

Aims: Phytoremediation is an effective method of remediating soils contaminated with heavy metals. However, it has some limitations in practical applications with regard to rare plant species, poor environmental adaptability, and long growth cycles. The dynamic response mechanisms of soil microbial communities during phytoremediation are still unclear, which restricts the optimization and promotion of this approach.

Methods and results: No ethical approval was required for this study. In this study, soil bacterial, fungal, and archaeal communities during the remediation of Cu-, Pb-, and Zn-contaminated soils with five industrial oilseed plants [Xanthium strumarium (XS), Bidens pilosa (BP), Kosteletzkya virginica (KV), Sesbania cannabina (SC), and Commelina communis (CC)] were analyzed using metagenome sequencing. Compared with soil contaminated with heavy metals, remediation through five industrial oilseed plants significantly reduced the content of heavy metals in the soil, with soil Cu, Pb, and Zn decreasing by 44.01%, 46.32%, and 27.62%, respectively, and WSCu, WSPb, and WSZn content decreasing by 28.23%, 50.68%, and 75.26%, respectively. Microbial diversity analysis showed that the phytoremediation significantly affected the soil microbial communities, with a significant decrease in archaeal diversity. Variation partitioning analysis and Mantel tests revealed that heavy metals and soil physicochemical properties significantly affected microbial communities, and heavy metals exerted stronger effects on archaeal communities. Meanwhile, soil contaminated with heavy metals was mainly dominated by fungal-fungal interactions, whereas phytoremediation increased the complexity of microbial symbiotic networks.

Conclusion: Collectively, these results provide fundamental insights into the microbial community structure during phytoremediation of heavy metal-contaminated soil, which may aid in the bioregulation of phytoremediation.