Lv Yichao, Liu Jianjun, Fan Zihan, Fang Mingjing, Xu Zhouying, Ban Yihui
School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, Hubei, China.
POWERCHINA Huadong Engineering Corporation Limited, Hangzhou 311122, Zhejiang, China.
Sci Total Environ. 2023 May 10;872:162233. doi: 10.1016/j.scitotenv.2023.162233. Epub 2023 Feb 14.
Arbuscular mycorrhizal fungi (AMF) have been demonstrated to be ubiquitous in aquatic ecosystems. However, their distributions and ecological functions are rarely studied. To date, a few studies have combined sewage treatment facilities with AMF to improve removal efficiency, but appropriate and highly tolerant AMF strains have not been explored, and the purification mechanisms remain unclear. In this study, three ecological floating-bed (EFB) installations inoculated with different AMF inocula (mine AMF inoculum, commercial AMF inoculum and non-AMF inoculated) were constructed to investigate their removal efficiency for Pb-contaminated wastewater. The AMF community structure shifts in the roots of Canna indica inhabiting EFBs during the three phases (pot culture phase, hydroponic phase and hydroponic phase with Pb stress) were tracked utilizing quantitative real-time polymerase chain reaction and Illumina sequencing techniques. Furthermore, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) were used to detect the Pb location in mycorrhizal structures. The results showed that AMF could promote host plant growth and enhance the Pb removal efficiency of the EFBs. The higher the AMF abundance, the better the effect of the AMF on Pb purification by EFBs. Both flooding and Pb stress decreased the AMF diversity but did not significantly inhibit the abundance. The three inoculation treatments showed different community compositions with different dominant AMF taxa in different phases, and an uncultured Paraglomus species (Paraglomus sp. LC516188.1) was found to be the most dominant (99.65 %) AMF in the hydroponic phase with Pb stress. The TEM and EDS analysis results showed that the Paraglomus sp. could accumulate Pb in plant roots through their fungal structures (intercellular mycelium, intracellular mycelium, etc.), which alleviated the toxic effect of Pb on plant cells and limited Pb translocation. The new findings provide a theoretical basis for the application of AMF in plant-based bioremediation of wastewater and polluted waterbodies.
丛枝菌根真菌（AMF）已被证明在水生生态系统中普遍存在。然而，它们的分布和生态功能很少被研究。迄今为止，一些研究已将污水处理设施与AMF结合以提高去除效率，但尚未探索合适且耐受性强的AMF菌株，其净化机制也仍不清楚。在本研究中，构建了三个接种不同AMF接种物（矿山AMF接种物、商业AMF接种物和未接种AMF）的生态浮床（EFB）装置，以研究它们对含铅废水的去除效率。利用定量实时聚合酶链反应和Illumina测序技术追踪了美人蕉根系在三个阶段（盆栽阶段、水培阶段和铅胁迫水培阶段）栖息于EFB期间AMF群落结构的变化。此外，使用透射电子显微镜（TEM）和能量色散X射线光谱（EDS）检测菌根结构中铅的位置。结果表明，AMF可促进宿主植物生长并提高EFB对铅的去除效率。AMF丰度越高，其对EFB净化铅的效果越好。水淹和铅胁迫均降低了AMF多样性，但未显著抑制其丰度。三种接种处理在不同阶段显示出不同的群落组成和不同的优势AMF分类群，并且发现一种未培养的类球囊霉属物种（类球囊霉属sp. LC516188.1）是铅胁迫水培阶段最主要的（99.65%）AMF。TEM和EDS分析结果表明，类球囊霉属物种可通过其真菌结构（胞间菌丝、胞内菌丝等）在植物根系中积累铅，这减轻了铅对植物细胞的毒性作用并限制了铅的转运。这些新发现为AMF在基于植物的废水和污染水体生物修复中的应用提供了理论依据。
