电活性微生物(EAM)通过促进细胞外电子转移在生物地球化学循环中起着至关重要的作用。它们对污染和水质差的河流沉积物表现出显著的适应性,为河流生态系统的可持续性做出了重要贡献。然而,EAM的分布和多样性仍然知之甚少。在这项研究中,采用16SrRNA基因高通量测序和实时荧光定量PCR技术,对中国南方珠江三角洲8条河流采集的160份样品进行了EAMs评估。结果表明,污染沉积物中的专门EAM群落表现出对水质和沉积物深度的响应。与干净的沉积物相比,受污染的沉积物显示EAMs群落(59属)的相对丰度增加4.5%,Geobacter和电缆细菌的丰度分别高45倍和17倍。此外,电缆细菌的丰度随着污染沉积物中沉积物深度的增加而降低,而L.variansGY32的丰度表现出相反的趋势。最后,Geobacter的丰度,电缆细菌,和L.variansGY32与所有样品中丝状微生物(FM)的丰度呈正相关,在污染的沉积物中具有更强的相互作用。这些发现表明,EAM对污染环境表现出更高的敏感性,特别是在属(种)水平,并表现出对高水平的酸挥发性硫化物的条件的适应性强,低溶解氧,硝酸盐氮升高。因此,可以操纵环境因素以优化EAM的生长和效率,以用于环境工程和自然恢复应用。
Electroactive microorganisms (EAMs) play a vital role in biogeochemical cycles by facilitating extracellular electron transfer. They demonstrate remarkable adaptability to river sediments that are characterized by pollution and poor water quality, significantly contributing to the sustainability of river ecosystems. However, the distribution and diversity of EAMs remain poorly understood. In this study, 16S rRNA gene high-throughput sequencing and real-time fluorescence quantitative PCR were used to assess EAMs in 160 samples collected from eight rivers within the Pearl River Delta of Southern China. The results indicated that specialized EAMs communities in polluted sediments exhibited variations in response to water quality and sediment depth. Compared to clean sediment, polluted sediments showed a 4.5% increase in the relative abundances of EAMs communities (59 genera), with 45- and 17-times higher abundances of Geobacter and cable bacteria. Additionally, the abundance of cable bacteria decreased with increasing sediment depth in polluted sediments, while the abundance of L. varians GY32 exhibited an opposite trend. Finally, the abundances of Geobacter, cable bacteria, and L. varians GY32 were positively correlated with the abundance of filamentous microorganisms (FMs) across all samples, with stronger interactions in polluted sediments. These findings suggest that EAMs demonstrate heightened sensitivity to polluted environments, particularly at the genus (species) level, and exhibit strong adaptability to conditions characterized by high levels of acid volatile sulfide, low dissolved oxygen, and elevated nitrate nitrogen. Therefore, environmental factors could be manipulated to optimize the growth and efficiency of EAMs for environmental engineering and natural restoration applications.