Laccase is a copper-containing polyphenol oxidase mainly produced from white rot fungi.Although laccase has great potential for industrial and biotechnological applications, the biological function of laccase has not been fully determined or confirmed.Previous research has suggested that fungal laccase may be involved in the defense against the oxidative stress, but there is little direct evidence supporting this hypothesis, and the mechanism by which laccase protects cells from oxidative stress also remains unclear.In this study, we cloned and characterized a new laccase gene, lac5930-1, and its corresponding full-length eDNA from a white rot fungus isolated from Shennongjia Nature Reserve in China by our laboratory.We found that the expression of this laccase gene from white rot fungus in Pichia pastoris can significantly enhance the resistance of yeast to H2O2-mediated oxidative stress.The expression of laccase in yeast was found to confer a strong ability to scavenge intracellular H2O2 and to protect cells from lipid oxidative damage.Based on this finding, the mechanism by which laccase gene expression increases resistance to oxidative stress was further investigated.We found that the laccase gene expression in Pichia pastoris could increase the level of glutathione-based antioxidative activity.The transcription of the laccase gene in Pichia pastoris could be enhanced by the oxidative stress caused by exogenous H2O2.The stimulation of laccase gene expression in response to exogenous H2O2 stress further contributed to the transcriptional induction of the genes involved in the glutathione-dependent antioxidative system.Taken together, these results suggest that the expression of the laccase gene in Pichia pastoris can enhance the resistance of yeast to H2O2-mcdiated oxidative stress by stimulating the glutathione-based antioxidative system to protect the cell from oxidative damage.Our work will provide insight into the function and mechanism of laccase involved in the defense against oxidative stress.This study may be of interest especially for the understanding of laccases physiological role and function.