Lignin-Degrading Enzymes From a Pathogenic Canker-Rot Fungus, Inonotus Obliquus Strain IO-B2 (NBRC 113408)

From the paper

Abstract

Inonotus obliquus is pathogenic fungus on living trees and has been widely used as a traditional medicine for cancer therapy. Although it has been reported that lignocellulose-degrading enzymes are involved in the early stage of host infection, the parasitic life cycle of this fungus has not been fully clarified. In the present study, we investigated the activities of lignin-degrading enzymes from I. obliquus and analyzed the degradation products. Our results revealed that I. obliquus is a pathogenic canker-rot fungus that does not produce lignin peroxidase (LiP), yet is capable of degrading the non-phenolic unit of lignin. The draft genome sequence of this fungus consisted of 21,203 predicted protein coding genes, of which 136 genes were estimated to be related to wood degradation. Furthermore, we found genes encoding putative versatile peroxidase (VP) and dye-decolorizing peroxidase (DyP), which are considered to be involved in the degradation of the non-phenolic unit of lignin. Thus, we cloned the cDNA encoding putative VP, referred as IO-Px, and characterized its molecular structure. From the above results, we suggested that: 1) IO-Px is a new member of MnP, and 2) the ability of I. obliquus to degrade non-phenolic lignin unit might arise from DyP properties.