The protective role of selenium against uptake and accumulation of cadmium and lead in white oyster () and pink oyster () mushrooms.

Mushrooms are bioaccumulators and have been used to produce Se-enriched foods. However, these fungi can also bioaccumulate potentially toxic metals, producing food dangerous to human health. It is known that co-exposure to Se plays a protective role against metal accumulation and toxicity in some organisms due to its antioxidant properties. Thus, this study aimed to evaluate the protective effect of Se(IV) and Se(VI) on elemental uptake and accumulation as well as proteins and protein-bound Se, Cd, and Pb distribution in mushrooms. Pink oyster and white oyster mushrooms showed high ability to bioaccumulate Se (19-205 µg g), Cd (4.5 to 18.8 µg g), and Pb (1.6 to 7.0 µg g). Growth substrate supplementation with Se(IV) or Se(VI) decreased the Cd total concentration in mushrooms by 4 to 89%, while Se(VI) increased the Pb total concentration by 9% to 187%, compared to growth in absence of Se. It was found that despite molecular weights distributions of mushrooms grown on Se(IV) and Se(VI)-supplemented substrates being similar, Se(VI) supplementation favoured Se interaction with proteins of medium molecular weight (17-44 kDa), when compared to supplementation with Se(IV). Therefore, we propose the supplementation of growth substrates with Se(VI) to reduce eventual Cd accumulation and produce Se-enriched oyster mushrooms.