Tolerance and Stress Response of Macrolepiota procera to Nickel

Abstract

Nickel (Ni) is an essential element for many organisms; however, it is very toxic at high concentrations and also depending on the species. In macrofungi the mechanisms underlying their Ni tolerance are poorly documented. This study examines, for the first time, the participation of the antioxidative system in Macrolepiota procera exposed to different Ni2+ concentrations and their relation with Ni tolerance. The effect of the pH on Ni tolerance was also evaluated. The fungus was cultivated on solid medium with different NiCl2 concentrations (0.05, 0.2, 0.8 mM) at pH 4, 6, and 8, and fungi growth and Ni uptake were determined. The antioxidative enzymes catalase (CAT) and superoxide dismutase (SOD) and the production of hydrogen peroxide H2O2 were evaluated on fungal submerged cultures within the first hours of Ni2+ exposure. Results showed that M. procera growth decreased when Ni2+ concentrations increased, reaching a maximum growth inhibition (>80%) up to 0.2 mM of NiCl2. Ni uptake increased proportionally to Ni increase in the medium. Both Ni tolerance and Ni accumulation were affected by medium pH. Microscope observations showed differences in the size of spores produced by fungi at different Ni concentrations. Ni exposure induced oxidative stress, as indicated by the production of H2O2, the levels of which seem to be regulated by the antioxidant enzymes SOD and CAT. The time variation pattern of SOD and CAT activities indicated that the former has a greater role in alleviating the stress. The results obtained suggested that tolerance of M. procera to Ni2+ is associated with the ability of this macrofungus to initiate an efficient antioxidant defense system.

Mineral Constituents of Edible Field Parasol (Macrolepiota procera) Mushrooms and the Underlying Substrate from Upland Regions of Poland: Bioconcentration Potential, Intake Benefits, and Toxicological Risk

“…For some of the sampled sites, Ag and Hg were highly bioconcentrated by M. procera and their BCF values reached more than 100. Earlier studies reported that M. procera has the ability to efficiently bioconcentrate Hg [54][55][56][57]. This species, apart from being rich in the essential elements (including Cu and Zn), is also rich in Cd, Pb, Hg, and Ag [2,14,26,40,56].…”

Tolerance and Bioaccumulation of Copper by the Entomopathogen Beauveria bassiana (Bals.-Criv.) Vuill. Exposed to Various Copper-Based Fungicides

“…For the highest doses of fungicides (2RD), copper content in B. bassiana decreased. It is known that fungi are able to accumulate significant amounts of metals (Gadd 1993;Figueiredo et al 2007;Baptista et al 2009), including entomopathogenic fungi (Popowska-Nowak et al 2004;Fomina et al 2005b). Although B. bassiana was able to solubilize copperbased fungicides, and therefore increase copper bioavailability and toxicity, this strain has shown high tolerance to those fungicides, especially to copper hydroxide and copper oxychloride.…”

The trace element content of top-soil and wild edible mushroom samples collected in Tuscany, Italy

“…On the basis of these results, without considering element speciation in fungi, As and Ni values in our samples are within actual background level ranges for mushrooms collected in unpolluted areas. Ni speciation in soils and macrofungi is of actual interest: increasing concentrations of the element induce an oxidative stress response in M. procera mycelium cultivated in Petri dishes, counter-balanced by superoxide dismutase and catalase activities (Baptista et al 2009). …”