Diverse and abundant arbuscular mycorrhizal fungi in ecological floating beds used to treat eutrophic water

Abstract An increasing number of investigations have demonstrated the universal existence of arbuscular mycorrhizal fungi (AMF) in aquatic ecosystems. However, little is known about the accurate distribution and functions of AMF inhabiting aquatic ecosystems, especially ecological floating bed (EFB) which was constructed for the remediation of polluted waterbodies.In this study, we collected root samples of Canna generalis, Cyperus alternifolius and Eichhornia crassipes from three EFBs floating on two eutrophic lakes in Wuhan, China, to investigate the resources and distribution of AMF in EFBs using Illumina Mi-seq technology. A total of 229 operational taxonomic units (OTUs) and 21 taxon from 348,799 Glomeromycota sequences were detected. Glomus was the most dominant AMF in the three EFBs while the second dominant AMF was related to Acaulospora. Different aquatic plant species exhibited varying degrees of AMF colonization (3.83%~71%), diversity (6~103 OTUs, 3~15 virtual taxa) and abundance (14~57551 sequences). Low AMF abundance but relatively high AMF diversity were found in C. alternifolius which is usually considered as non-mycorrhizal, demonstrating the high accuracy of Illumina sequencing. In addition, results from this study suggested a lognormal species abundance distribution was observed across AMF taxa in the three plant species, and the AMF community composition was closely related to pH, nitrogen and phosphorus.Overall, our data demonstrated that diverse and abundant AMF communities were living in EFBs, and the AMF community composition was closely related to the water quality of eutrophic lakes treated by EFBs, providing potential possibility for the applications of AMF in plant-based bioremediation of wastewater.