Effect of copper-induced oxidative stress on sclerotial differentiation and antioxidant properties of Penicillium thomii PT95 strain.

Penicillium thomii PT95 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 and antioxidant properties of PT95 strain. The results showed that the time of exudates initiation, sclerotial initiation and sclerotial maturation of PT95 strain were advanced in 1-2 days under the copper-induced oxidative stress growth conditions. The analytical results of sclerotial biomass, carotenoids content in sclerotia showed that copper-induced oxidative stress favored the sclerotial differentiation and biosynthesis of carotenoids. Under the copper-induced oxidative stress growth conditions, the total phenolics content and DPPH free radical scavenging activity of sclerotia of this fungus were decreased as compared with the control. However, the oxidative stress induced by a lower amount of CuSO₄ in media could enhance significantly the reducing power of sclerotia.