Wang Yixiu, Cheng Hongyan, Li Yuenan, Ning Ruiyan, Lv Yonghui, Wang Qing, Zhang Haibo, Liu Na
College of Resource and Environment, Shanxi Agricultural University, Taigu 030801, China.
Microorganisms. 2024 Dec 1;12(12):2471. doi: 10.3390/microorganisms12122471.
Nanoplastics (NPs) and cadmium (Cd) coexist in soil, but the combined effects of NPs and Cd on the rhizosphere bacterial community remain unknown. In this study, high-throughput sequencing and PICRUSt2 functional analysis were employed to explore the individual and combined effects of polystyrene (PS) NPs (low concentration [N1, 100 mg·kg] and high concentration [N2, 1000 mg·kg]) and Cd (low concentration [C1, 0.6 mg·kg] and high concentration [C2, 4 mg·kg]) on the diversity, structural composition, and function of the rhizosphere bacterial community associated with Hance. Individually, PS NPs and Cd significantly reduced the soil pH, while the combined treatments induced a more significant decrease in pH. In contrast, combined PS NPs and Cd significantly increased the diethylenetriaminepentaacetic acid-Cd (DTPA-Cd) and total Cd concentrations. Compared with individual treatments, C2N2 significantly increased DPTA-Cd by 4.08%. N1 had no significant effect on the Chao1, observed species, or Shannon indices, while N2 significantly reduced the richness and diversity of the rhizosphere bacteria and altered their community structure. Furthermore, adding PS NPs exacerbated the effect of Cd on rhizosphere bacterial communities. Compared with individual Cd treatments, C2N2 significantly reduced the relative abundances of Actinobacteriota, Bacteroidota, Crenarchaeota, and Myxococcota by 19.76%, 2.01%, 1.49%, and 2.00%, respectively, and significantly increased the relative abundance of Acidobacteriota by 16.05%. A cluster heat map showed that the combined treatments attenuated glycan biosynthesis and metabolic function and enhanced the metabolism of cofactors and vitamins. These findings illuminate rhizosphere processes under co-contamination with heavy metals and PS NPs, supporting the practical application of phytoremediation to alleviate combined Cd and PS NP pollution.
纳米塑料（NPs）和镉（Cd）在土壤中共同存在，但NPs和Cd对根际细菌群落的联合影响尚不清楚。在本研究中，采用高通量测序和PICRUSt2功能分析，探讨聚苯乙烯（PS） NPs（低浓度[N1，100 mg·kg]和高浓度[N2，1000 mg·kg]）和Cd（低浓度[C1，0.6 mg·kg]和高浓度[C2，4 mg·kg]）对与鸡骨草相关的根际细菌群落多样性、结构组成和功能的单独及联合影响。单独来看，PS NPs和Cd显著降低了土壤pH值，而联合处理导致pH值下降更为显著。相反，PS NPs和Cd联合显著提高了二乙烯三胺五乙酸镉（DTPA-Cd）和总Cd浓度。与单独处理相比，C2N2使DPTA-Cd显著增加了4.08%。N1对Chao1、观测物种或香农指数没有显著影响，而N2显著降低了根际细菌的丰富度和多样性，并改变了其群落结构。此外，添加PS NPs加剧了Cd对根际细菌群落的影响。与单独的Cd处理相比，C2N2使放线菌门、拟杆菌门、泉古菌门和粘球菌门的相对丰度分别显著降低了19.76%、2.01%、1.49%和2.00%，并使酸杆菌门的相对丰度显著增加了16.05%。聚类热图显示，联合处理减弱了聚糖生物合成和代谢功能，并增强了辅因子和维生素的代谢。这些发现阐明了重金属和PS NPs共同污染下的根际过程，支持了植物修复在缓解Cd和PS NP联合污染方面的实际应用。
