Toxicity of metal cations and phenolic compounds to the bioluminescent fungus Neonothopanus gardneri

Abstract

Fungi play a key role in the soil ecosystem, where they occupy the first level of the food chain. Hence, they are considered suitable model organisms to conduct ecotoxicological assays for the evaluation of soil condition after proper soil extraction. Fungi bioluminescence-based bioassays are useful considering that their luminescence is an early toxicity endpoint and light emission a promptly detectable signal. In this paper, we describe a toxicological bioassay that relies on a 24-h variation of total light emitted by the mycelium of the bioluminescent fungus Neonothopanus gardneri when exposed to a toxicant. The current bioluminescent assay, which uses a fungus of the Omphalotus lineage, fills a gap covering all the representative species of bioluminescent fungi. Among the compounds tested here, Cd(II) showed the highest toxicity, followed by 4-nitrophenol, phenol and Cu(II), respectively. We also found that N. gardneri presents a predictable bioluminescence and growth pattern, and is highly sensitive to these compounds. The aforementioned characteristics offer valuable advantages and make N. gardneri the ideal candidate for toxicological studies with basidiomycetes.