Molecular Characterization of Fungal Biodiversity in Long-Term Polychlorinated Biphenyl-Contaminated Soils

Abstract

Polychlorinated biphenyls (PCBs) belong to the organic pollutants that are toxic to humans and harmful to environments. Numerous studies dealing with the impact of PCBs on soil microorganisms have focused on bacterial communities. The effects of PCBs on fungal communities in three different PCB-polluted soils from former industrial sites were investigated using high-throughput sequencing of the internal transcribed spacer 1 region. Significant differences in fungal alpha diversity were observed mainly due to soil physico-chemical properties. PCBs only influenced the richness of the fungal communities by increasing it. Fungal composition was rather strongly influenced by both PCBs and soil properties, resulting in different communities associated with each soil. Sixteen Ascomycota species were present in all three soils, including Stachybotrys chartarum, Fusarium oxysporum, Penicillium canescens, Penicillium chrysogenum,Penicillium citrosulfuratum and Penicillium brevicompactum, which are usually found in PCB-polluted soils, and Fusarium solani, Penicillium canescens, Penicillium citrosulfuratum and Penicillium chrysogenum, which are known PCB degraders. This study demonstrated that PCBs influence the richness and the composition of fungal communities. Their influence, associated with that of soil physico-chemical properties, led to distinct fungal communities, but with sixteen species common to the three soils which could be considered as ubiquitous species in PCB-polluted soils.

Prokaryotic, Microeukaryotic and Fungal Composition in a Long-Term Polychlorinated Biphenyl-Contaminated Brownfield

“…The studied site was heterogeneously contaminated by PCB indicating that pollution concentration was not location dependent. Literature reported other PCB polluted soils that presented heterogeneous pollution with PCB concentrations varying from 1 mg.kg -1 dry mass [45] to over than 800 mg.kg -1 dry 16 mass [25]. This ranked the Pont de Claix brownfield of this study as a "moderate" polluted site despite the weakly industrial painting production activity occurring in the past decades.…”

“…By using 454 pyrosequencing, more recent in situ studies identified Proteobacteria, Actinobacteria, Firmicutes and Basidiomycota phyla, including species already known to transform PCBs (Stella et al, 2017;Zenteno-Rojas et al, 2020). Other studies also reported that PCB contamination increased soil fungal richness and promoted the development of bacterial species able to metabolize these pollutants [24,25]. But among these studies focusing on microbial diversity under PCB contaminated ecosystems, none investigated micro-eukaryotes (other than Fungi) neither archaeal diversity.…”