Synergistic effect on wood degradation by interspecific interactions of white and brown rot fungi

Wood-rotting fungi play an important role in carbon and nitrogen cycles in nature. They have different strategies for wood degradation and utilization of nutrients. Traditionally, wood-rotting fungi have been classified as white rot, brown rot, and soft rot fungi based on the differences in their wood decay mechanisms. Basidiomycota white rot fungi secrete a wide range of lignocellulose degrading enzymes being the most efficient lignin degraders in nature, while brown rot species primarily depolymerize wood cellulose and hemicellulose leaving modified lignin behind. Ascomycota soft rot fungi depolymerize wood polysaccharides and are able to convert lignin only to some extent. The interspecific interactions of wood-rotting fungi can be synergistic, antagonistic, or additive depending on the fungal and wood species. In nature, the composition of fungal communities and the repertoire of their secreted enzymes change gradually during the succession of the wood decay stages. However, the interaction of fungal communities on wood is relatively poorly understood compared to the action of individual fungal species during wood decay. The hypothesis of this study is that the fungal interactions activate the process of the wood degradation when fungi compete for limited resources. To test the hypothesis, three specific aims were provided: 1) to discover efficient wood-rotting fungal species for co-cultivation tests, 2) to investigate the effects of the fungal co-cultivation in wood degradation, and 3) to analyse the changes of the enzyme activities and the sugar components of the wood by fungal co-cultivation. Based on the screening of fungal strains isolated from fruiting bodies and rotten woods, two brown rot fungi Antrodia sinuosa and Gloeophyllum sepiarium; three white rot fungi Bjerkandera adusta, Heterobasidion annosum, and Phlebiopsis gigantea; and three Ascomycota Trichoderma polysporum, Phoma sp., and Scytalidium lignicola were selected for co-cultivations on different wood species. The wood weight losses, enzyme activities, sugar constituents of woody substrates, and mycelial interactions were analysed from single and co-cultivations on birch, spruce, and pine wood. In the co-cultivations, synergistic, antagonistic, and additive effects were observed depending on the fungal species and wood substrate. This study provides the basic knowledge on enzymatic lignocellulose degradation by fungal communities and shows the potential of interspecific fungal interactions in wood degradation.

Grantor dc:publisher

Helsingin yliopisto

Year dc:date.issued

2022

Author dc:creator

• Sugano, Junko

• faculty of Agriculture and Forestry

Statement dc:rights

• Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
• This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
• Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden.

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/10138/339518

OAI record oai:identifier

https://helda.helsinki.fi/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Ahelda.helsinki.fi%3A10138%2F339518