Fig 7.

Metabolic pathways of HBA, VA, and SA in the white-rot fungus P. chrysosporium. HBA is estimated to convert to hydroquinone and protocatechuic acid (PCA). HQ is hydroxylated to THB by PcFPMO2 (12), while PCA is decarboxylated to THB, which is then ring cleaved by intradiol dioxygenase 1 (PcIDD1) (11, 13). VA is estimated to convert to PCA and MHQ. MHQ is ring cleaved (this study) or be converted to THB and MTHB, which are then cleaved (10–13). SA is estimated to convert to hydroxyl vanillic acid (HVA) and DMHQ. HVA is converted to MTHB, while DMHQ is ring cleaved (this study) or may be converted to MTHB. Dotted arrows indicate the estimated reactions; solid arrows indicate the reactions by identified enzymes: PcMHQD (this study), PcFPMO2 (12), PcIDD1(13), and PcIDD2 (13).