Contrasting soil fungal communities at different habitats in a revegetated copper mine wasteland

Abstract

Little is known about the responses of soil fungal communities to revegetation of mine wastelands, representing a major gap in the knowledge needed to improve the performances of revegetation schemes for mine wastelands. To shed some light on this matter, we reestablished 4000 m 2 of vegetation on an extremely acidic (pH 2.5) copper mine tailings pond and collected soil samples from three different types of habitats: amended layer of the reclaimed tailings (ALRT), unamended layer of the reclaimed tailings (ULRT), and unreclaimed tailings (UT). Soil fungal communities in the 120 samples collected in two consecutive years were characterized via high-throughput sequencing. The fungal diversities at ALRT and ULRT were found to be significantly higher than those at UT. Ascomycota whose relative abundance ranged from 74.5% to 98.4% was the most predominant phylum across all habitats, exhibiting the lowest predominance at ALRT. Two acidophilic fungal genera, Acidomyces and Acidiella, dominated UT with relative abundances being as high as 37.8% and 15.2%, respectively. In contrast, three genera with plant growth-promoting species (Talaromyces, Trichoderma and Penicillium) were abundant at ULRT and ALRT. Remarkably, their relative abundances at ULRT could be up to 29.0%, 26.9% and 9.7%, respectively. The three types of habitats differed considerably in the overall soil fungal community composition at species level, which became more pronounced as time progressed. The abovementioned differences between habitats in soil fungal community features were related to the reduced availability of soil copper and zinc.These results improved our understanding of fungal ecology of mine wastelands.

Clary Sage Cultivation and Mycorrhizal Inoculation Influence the Rhizosphere Fungal Community of an Aged Trace-Element Polluted Soil

“…This observation is consistent with recently published studies carried out in both agricultural or aged TE-polluted soils [ 7 , 14 , 17 , 39 , 61 , 62 , 63 ]. Ascomycota has, in particular, been depicted as the prevalent fungal phylum in various polluted or unpolluted environments due to their diversity in terms of metabolic capacities, owing to the wide variety of enzymes they produce [ 7 , 14 , 63 ]. They have, for instance, been reported as key decomposers of crop residues in agricultural soils [ 14 , 64 ].…”

“…In the case of Ascomycota and Basidiomycota , previous reports have pointed to an induction of the expression of genes coding for metallothionein or phytochelatin synthase, which are involved in fungal cell protection against harmful TE effects [ 66 , 67 , 68 ]. Regarding the fungal diversity in the TE-polluted site, it appeared similar to (or even slightly higher than) previous results published elsewhere in the literature, considering revegetated or agricultural TE-polluted soils, whatever the richness or diversity index [ 3 , 7 , 16 , 17 , 69 ]. This could notably be explained by the water pH being close to neutral and a soil organic matter content which can be considered as slightly higher than average, in comparison with reference indicators, in our experimental conditions.…”

“…Notably, Ascomycota and Basidiomycota were predominant, as they accounted for more than 90% of the relative abundance together. This observation is consistent with recently published studies carried out in both agricultural or aged TE-polluted soils [7,14,17,39,[61][62][63]. Ascomycota has, in particular, been depicted as the prevalent fungal phylum in various polluted or unpolluted environments due to their diversity in terms of metabolic capacities, owing to the wide variety of enzymes they produce [7,14,63].…”

“…Among soil microbial communities, fungi represent important biomass, providing the key function of organic matter decomposition leading to nutrient cycling and performing crucial roles in humification, mineralization, and soil aggregation processes [ 5 , 6 ]. Hence, fungi play a central role in the functioning and fertility of most natural and managed ecosystems [ 3 , 5 , 6 , 7 ]. Some fungi, such as arbuscular mycorrhizal fungi (AMF) belonging to the phylum Glomeromycota, are additionally able to form symbiotic associations with more than 80% of terrestrial plants [ 8 ].…”

“…Notably, TEs can accumulate in cultivated plants, causing growth and productivity issues as well as possible contamination of the food chain, which may be responsible for various disorders and diseases in human beings [ 11 , 14 , 15 , 16 ]. It has previously been shown that revegetation of TE-polluted areas could help towards restoring the disturbed ecosystem’s functioning, as well as providing aesthetic value and a reduction in wind and water erosion phenomena [ 7 , 17 , 18 ]. In that regard, among other potential remediation options, phytomanagement has attracted significant attention.…”