A lower cadmium accumulating strain of Agaricus brasiliensis produced by 60Co-γ-irradiation

Agaricus brasiliensis, an edible mushroom with medicinal properties, has a tendency to accumulate high concentrations of heavy metals, especially cadmium. To address this issue, strains with low Cd accumulation must be developed. To breed a low-Cd-accumulating, high yield, and high-quality strain, mycelial fragments of A. brasiliensis were mutagenized with different doses of Co-60-gamma-irradiation. The resulting mutants were screened based on morphology, cell and molecular biology, and fruiting behavior and one mutant strain with desirable properties across all criteria was identified. Analysis of fruiting bodies revealed that the contents of Cd, Pb and As in the mutant decreased by 51.07%, 10.81% and 29.73%, respectively, compared with the control (parent) strain. Furthermore, the mutant, named strain J(5), displayed higher biological efficiency (40.30% +/- 1.19%), and higher crude protein and crude fat content (14.68% +/- 4.20% and 10.70% +/- 0.71%, respectively) than the control. The essential amino acids threonine, valine, methionine, isoleucine, leucine and histidine increased by 15.0%, 15.45%, 4.10%, 10.58%, 8.97% and 8.70%, respectively, in the mutant compared with the control. Overall, a new strain of A. brasiliensis was obtained with higher yield, higher nutrient content and lower Cd content.