Hydrogen sulfide and calcium effects on cadmium removal and resistance in the white-rot fungus Phanerochaete chrysosporium

Hydrogen sulfide (H 2 S), an emerging gas transmitter, has been shown to be involved in multiple intracellular physiological and biochemical processes. In this study, the effects of hydrogen sulfide coupled with calcium on cadmium removal and resistance in Phanerochaete chrysosporium were examined. The results revealed that H 2 S enhanced the uptake of calcium by P. chrysosporium to resist cadmium stress. The removal and accumulation of cadmium by the mycelium was reduced by H 2 S and Ca 2+ pretreatment. Moreover, oxidative damage and membrane integrity were alleviated by H 2 S and Ca 2+ . Corresponding antioxidative enzyme activities and glutathione were also found to positively respond to H 2 S and Ca 2+ , which played an important role in the resistance to cadmium-induced oxidative stress. The effects of hydroxylamine (HA; a hydrogen sulfide inhibitor) and ethylene glycol-bis-(2-aminoethylether)- N , N , N ′, N ′-tetraacetic acid (EGTA; a calcium chelator) toward H 2 S and Ca 2+ and their cross-interactions confirmed the positive roles and the potential crosstalk of H 2 S and Ca 2+ in cadmium stress resistance. These findings imply that the protective effects of H 2 S in P. chrysosporium under cadmium stress may occur through a reduction in the accumulation of cadmium and promotion of the antioxidant system, and the H 2 S-regulated pathway may be associated with the intracellular calcium signaling system. Key points • Altered monoterpenoid tolerance mainly related to altered activity of efflux pumps. • Increased tolerance to geranic acid surprisingly caused by decreased export activity. • Reduction of export activity can be beneficial for biotechnological conversions.