Potential of autochthonous fungal strains isolated from contaminated soils for degradation of polychlorinated biphenyls.

Up to now, most studies on polychlorinated biphenyl (PCB) bioremediation have examined the ability of model fungal strains to biodegrade PCBs. Yet, there is limited information concerning the potential of autochthonous filamentous fungal strains in the biodegradation of PCBs and their possible use in the environmental technologies. In this study, we investigated the capacity of autochthonous fungal strains in the biodegradation of PCBs by isolating 24 taxa from former industrial sites highly contaminated by PCBs. Microscopic and molecular analyses using the internal transcribed spacer (ITS) region revealed that the fungal strains belonged to the phyla Ascomycota (19 strains) and Zygomycota (five strains). The chromatography gas analysis revealed evidence of degradation of seven PCB congeners. With the exception of Circinella muscae which presented no degradation potential, the other fungal strains exhibited a rate of biodegradation ranging from 29 to 85 % after 7 d of incubation in liquid medium. Among these strains, Doratomyces nanus, Doratomyces purpureofuscus, Doratomyces verrucisporus, Myceliophthora thermophila, Phoma eupyrena, and Thermoascus crustaceus showed remarkable degradation ability (>70 %) regardless of the number of chlorine substituents on the biphenyl nucleus and a high tolerance towards PCBs. To our knowledge, this is the first study that demonstrates the ability of PCB degradation by these species and indicates the potential effectiveness of some autochthonous fungal strains in bioremediation systems.info:eu-repo/semantics/publishe

Industrial Cd-Contaminated Soil Bioaugmented with Absidia cylindrospora : Influence on the Mineralogical Speciation of Cadmium

International audienceNowadays, trace metal contamination of soils is a worldwide concern. In the soil, the trace metals are distributed within different mineralogical fractions, which influence the transfers and the bioavailability, then the associated toxic risk. This study aims to investigate how the development of selected fungal mycelium influences the mineralogical speciation of cadmium. In a microcosm experiment with an industrial soil contaminated by various metal, including Cd, bioaugmentation experiments with the fungus Abisdia cylindrospora were conducted. A. cylindrospora showed a good development in the microcosm. Sequential extraction procedure highlighted the decrease of the potentially available fraction (5%) after 20 days of incubation. Most of the variations occur in the reducible and the oxidable fractions

Comparison of tolerance and biosorption of three trace metals (Cd, Cu, Pb) by the soil fungus Absidia cylindrospora

International audienc

Use of soil fungi in the biosorption of three trace metals (Cd, Cu, Pb): promising candidates for treatment technology?

International audienc

Differences in fungal communities associated to Festuca paniculata roots in subalpine grasslands

International audienceMycorrhizal fungi or endphytes colonize plant roots and their occurrence and composition depend on biotic and abiotic characteristics of the ecosystem. We investigated the composition of these microbial communities associated with Festuca paniculata, a slow growing species, which dramatically impacts functional plant diversity and the recycling of organic matter in subalpine grasslands. F. paniculata individuals from both mown and unmown grasslands were randomly collected and the microscopic observation of the plant roots revealed a difference in fungal colonization according to management. The ITS regions of root-associated fungi were amplified, cloned and sequenced. Bioinformatic analysis revealed a total of 43 and 35 phylotypes in mown and unmown grasslands respectively, highlighting a remarkable difference in the composition between both fungal communities. The phylotypes were assigned to 9 classes in which two classes Eurotiomycetes and Lecanoromycetes were specific to mown grasslands, while Tremellomycetes were specific to unmown grasslands and only five phylotypes were common to both locations. The comparative analysis of fungal lifestyles indicated the dominance of saprobes and a large proportion of endophytes compared to the mycorrhizal fungi (7/1 and 11/2 phylotypes in mown and unmown grasslands, respectively). Endophyte richness was greater in the unmown gassland than in the mown grassland and their relative proportion was twice higher. Our results suggest that endophytes may offer potential resources to F. paniculata and play an important role in the regulation of plant diversity

Molecular screening of xerophilic Aspergillus strains producing mycophenolic acid

International audienc

Responses of above- and below-ground fungal symbionts to cessation of mowing in subalpine grassland

The cessation of mowing in subalpine grasslands promotes the dominance of Festuca paniculata leading to the reduction in plant diversity. Moreover, it affects positively the abundance of Epichloë sp. inhabiting F. paniculata leaves and negatively the soil density of arbuscular mycorrhizal fungi (AMF). We explored how the cessation of mowing influences root AMF communities in F. paniculata and the neighboring plants, and Epichloë sp alkaloids. Thirteen AMF operational taxonomical units were found. The neighboring plants affected positively the abundances of Aalpin and GLOM_7 whereas the interaction plant/management type influenced significantly Claroide_1, GLOM_1 and GLOM_7. The N-formylnorloline, produced by Epichloë sp. increased in unmown grassland. Hence, the cessation of mowing, coinciding with the high abundance of endophyte alkaloid, affected root-associated AMF with differential responses at the abundance level. The N-formylnorloline could be one compound underpinning the dynamic of plant diversity with a resulting structuration of AMF in subalpine grasslands.info:eu-repo/semantics/publishe