Soil fungal diversity and functionality are driven by plant species used in phytoremediation

Abstract

Soil biodiversity loss due to pollution may affect ecosystem services negatively. This environmental problem may be solved by phytoremediation, which is an effective strategy to manage and remediate contaminated areas. During this remediation process, the establishment of plant communities may improve soil fungal community structure and, in particular, may favour mycorrhizal symbiotic associations. As a consequence, afforestation of degraded lands will have different outcomes on fungal diversity and functionality, which will depend on the selected tree and shrub species.We analysed soil fungal diversity and functional guilds by high-throughput sequencing of environmental DNA in a trace element contaminated area, part of a large scale phytoremediation project running for 20 years. We selected five habitats for comparison purposes: three under the canopy of selected tree species (wild olive, white poplar and stone pine), adjacent treeless areas (grassland) and non-remediated areas (bare soil).Soil fungal diversity and richness seemed to be enhanced by phytoremediation. White poplar soil had the highest diversity and richness compared to wild olive and stone pine.Fungal communities were especially different between stone pine, with soils rich in organic C and high C:N ratio, and grassland soils.We identified 9,428 fungal OTUs from which 1,283 were assigned to a unique functional guild; the most abundant belonging to saprotrophic, plant pathogenic and ectomycorrhizal functional guilds. Ectomycorrhizal fungi were more abundant in soils under ectomycorrhizal host trees. Saprotrophs were abundant in grassland and wild olive soils, while plant pathogens were abundant in non-remediated soils. 3The remediation of soils (clean-up and amendment addition) allowed the natural establishment of grassland habitats throughout the study area, increasing fungal diversity, richness, taxonomy and functionality, when compared to non-remediated soils. Tree afforestation allowed the establishment of a forest type community bringing a further recruitment of fungal taxa, mainly the ectomycorrhizal fungal guild. Afforestation with different tree species showed species-specific effects on soil N, organic C, Ca and C:N ratio which led to increased spatial heterogeneity in areas with potential to recruit a wider diversity of fungi.

Alternate drip irrigation regulates the soil fungal community structure and metabolic function based on root–fungus interactions

“…ADI can improve the composition of soil aggregates and soil aeration, while surface drip irrigation is prone to causing relative soil compaction in the tomato root zone (Lehmann et al, 2017) and better promotes the growth of Mucoromycota. Basidiomycota can produce a large number of hydrophobic hyphae (Lehmann et al, 2020) and participate in the construction of plant ectomycorrhizae (Gil‐Martínez et al, 2021); the relatively high number of root forks of A70 is likely closely related to the significant increase in the relative abundance of Basidiomycota in this treatment. This relationship is similar to the results of Milan et al (2015), except that we achieved it by conditioning the soil in a greenhouse.…”

“…A70 produced the least soil drought stress on the root system, which was conducive to the division of root cells (Zia et al, 2021). Therefore, A70 resulted in a higher number of root forks than CK, which provided more sites for interactions with ectomycorrhizae, promoted the growth of Basidiomycota (Gil‐Martínez et al, 2021), and reduced the complexity of trophic modes involving Basidiomycota (Table S1.). Previous studies have shown that soil moisture status alters root structure, thereby altering fungal community shifts associated with changes in root traits (Deveautour et al, 2018).…”

Mycorrhizal-Assisted Phytoremediation and Intercropping Strategies Improved the Health of Contaminated Soil in a Peri-Urban Area

“…Additionally, some unidentified orders of Ascomycota were detected in high abundance in soils where alfalfa and mycorrhizal poplars were present. Some studies have recognized the key role of the phylum Ascomycota in environments contaminated with organics (Aranda, 2016) and metals (Gil-Martínez et al, 2021). However, the role of Ascomycota in the transformation of soil contaminants remains poorly understood.…”

Soil fungal community characteristics vary with bamboo varieties and soil compartments

“…Different plant varieties therefore may lead to variation in fungal community characteristics. For example, differences were observed in the diversity, composition and symbiotic network of soil fungal communities among different varieties of Zea mays in China ( Kong et al, 2020 ; Gil-Martínez et al, 2021 ). However, Li et al (2018) found that rice variety did not significantly affect fungal abundance or community composition.…”