Effect of copper-induced oxidative stress on sclerotial differentiation and antioxidants contents of Penicillium thomii Q1.

Penicillium thomii Q1 strain was able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. The aim of this work was to determine the effects of copper-induced oxidative stress on the sclerotial differentiation, biosynthesis of some endogenous antioxidants, and the activities of some antioxidative enzymes of Q1 strain. The results showed that the oxidative stress induced by copper was clearly dependent on the CuSO4 concentrations in media, and characterized by the initiation of lipid peroxidation. Under the copper-induced oxidative stress conditions, the time of exudates initiation, sclerotial initiation and sclerotial maturation of Q1 strain were advanced in 1-2 days. The analytical results of sclerotial biomass, carotenoids, and ascorbate contents showed that copper-induced oxidative stress favored the sclerotial differentiation and biosynthesis of carotenoids and ascorbate. The oxidative stress induced by a lower amount of CuSO4 in media could enhance significantly the superoxide dismutase and catalase activities of Q1 strain.