Up-regulation of MAP kinase HOG1 gene of white rot fungus Phlebia sp. MG-60 inhibits the ethanol fermentation and mycelial growth. Phlebia sp. MG60 strain:TUFC40001

The conversion of wood biomass to replace fossil resources is expected for the sustainable production of various chemicals, but lignin is an obstacle to the effective use of polysaccharides. The white-rot fungus Phlebia sp. MG-60 has been reported to selectively degrade lignin in oak wood under aerobic solid conditions, and then under semi-aerobic liquid cultures conditions, this fungus begins to saccharify cellulose from delignified oak wood to produce ethanol. Biomass conversion by white rot fungi may change in response to environment, but little is known about the effects of the environmental response sensor on growth and ethanol fermentation in white rot fungi. In this study, we focused on the yeast Hog1 homologue in the white-rot fungus Phlebia sp. MG-60, MGHOG1, which is presumed to play an important role in responding to changes in the osmotic stress. We generated MGHOG1 overexpressing (OE) transformants in Phlebia sp. MG-60. Under salinity stress, OE strains showed slower mycelial growth compared to wild-type. The mycelial growth and ethanol fermentation was suppressed in liquid cultures by overexpression of MGHOG1. These data suggest that MGHOG1 regulates the glucose metabolism flow of Phlebia sp. MG-60 and affects ethanol fermentation, mycelial growth. The present study provides novel insights to regulate biomass conversion by white rot fungi.