Arsenic Metabolism, Toxicity and Accumulation in the White Button Mushroom Agaricus bisporus

Abstract

Mushrooms have unique properties in arsenic metabolism. In many commercial and wild-grown mushrooms, arsenobetaine (AsB), a non-toxic arsenical, was found as the dominant arsenic species. The AsB biosynthesis remains unknown, so we designed experiments to study conditions for AsB formation in the white button mushroom, Agaricus bisporus. The mushrooms were treated with various arsenic species including arsenite (As(III)), arsenate (As(V)), methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and trimethylarsine oxide (TMAsO), and their accumulation and metabolism were determined using inductively coupled mass spectrometer (ICP-MS) and high-pressure liquid chromatography coupled with ICP-MS (HPLC-ICP-MS), respectively. Our results showed that mycelia have a higher accumulation for inorganic arsenicals while fruiting bodies showed higher accumulation for methylated arsenic species. Two major arsenic metabolites were produced in fruiting bodies: DMAs(V) and AsB. Among tested arsenicals, only MAs(V) was methylated to DMAs(V). Surprisingly, AsB was only detected as the major arsenic product when TMAsO was supplied. Additionally, AsB was only detected in the fruiting body, but not mycelium, suggesting that methylated products were transported to the fruiting body for arsenobetaine formation. Overall, our results support that methylation and AsB formation are two connected pathways where trimethylated arsenic is the optimal precursor for AsB formation.

Management of Water Supply in the Cultivation of Different Agaricus bisporus Strains

“…Another difference verified between these strains was related to the greater weight of the mushrooms in ABI 19/03 compared to ABI 11/19 in the first and third flushes. Dong et al [38] highlighted that most of the genes present in the genome of A. bisporus still do not have a characterization of their function in the development of the fungus. Other authors also mentioned that different responses in cultivation occur due to the enzymatic activity of laccase and peroxidase, as well as suitability to the environment and region [24,39,40].…”