title: Identification of two mutations that cause defects in the ligninolytic system through an efficient forward genetics in the white-rot agaricomycete Pleurotus ostreatus.
abstract: White-rot fungi play an important role in the global carbon cycle because they are the species that almost exclusively biodegrade wood lignin in nature. Lignin peroxidases (LiPs), manganese peroxidases (MnPs) and versatile peroxidases (VPs) are considered key players in the ligninolytic system. Apart from LiPs, MnPs and VPs, however, only few other factors involved in the ligninolytic system have been investigated using molecular genetics, implying the existence of unidentified elements. By combining classical genetic techniques with next-generation sequencing technology, they successfully showed an efficient forward genetics approach to identify mutations causing defects in the ligninolytic system of the white-rot fungus Pleurotus ostreatus. In this study, they identified two genes - chd1 and wtr1 - mutations in which cause an almost complete loss of Mn2+-dependent peroxidase activity. The chd1 gene encodes a putative chromatin modifier, and wtr1 encodes an agaricomycete-specific protein with a putative DNA-binding domain. The chd1-1 mutation and targeted disruption of wtr1 hamper the ability of P. ostreatus to biodegrade wood lignin. Examination of the effects of the aforementioned mutation and disruption on the expression of certain MnP/VP genes suggests that a complex mechanism underlies the ligninolytic system in P. ostreatus.
authors.affiliation: Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Nakazawa
authors.affiliation: Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Izuno
authors.affiliation: Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: Kodera
authors.affiliation: Department of Applied Microbiology, Forestry and Forest Product Research Institute, P O Box 16, Tsukuba-Norin, 305-8687, Japan.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Miyazaki
authors.affiliation: Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sakamoto
authors.affiliation: Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Isagi
authors.affiliation: Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Honda
mesh_terms: D001673:Biodegradation, Environmental; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D008031:Lignin / Q000378:metabolism*; D009154:Mutation; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism; D020076:Pleurotus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D014934:Wood / Q000378:metabolism / Q000382:microbiology
chemical_list: D005656:Fungal Proteins; D008031:Lignin; D010544:Peroxidases; C042858:lignin peroxidase; C051129:manganese peroxidase