Changes in Fungal Community and Gene Expression of Specific Ligninolytic Enzymes in Response to Wood Decay

Abstract

Microbial communities, particularly Basidiomycota fungi, play crucial roles in ecosystem functioning, including wood decay and the recycling of carbon and nutrients. However, the relationship between fungal diversity and wood decomposition remains poorly understood. This study investigated the effect of fungal community, gene expression, and activity of specific ligninolytic enzymes on wood decay in pine, cedar, and alkaline copper quaternary (ACQ)-treated pines for 30 months. The fungal community and gene expression levels were characterized using DNA sequencing and RT–qPCR, respectively. The Azure-B assay and phenol red test were conducted to determine enzyme activity. The results showed that non-wood-decaying fungi dominated early in the decay process, whereas true wood-decaying fungi, such as Trametes sp., dominated later. Visual decay ratings and modulus of elasticity data implied that pine deteriorated more than cedar and that ACQ treatment helped prevent deterioration of pine. The gene expression levels of lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lcc) produced by the predominant fungus, T. elegans, varied depending on the wood type. LiP expression was the highest in ACQ-treated pines after 10 months of treatment. MnP expression was higher in both decay-resistant woods (cedar- and ACQ-treated pines) than in untreated pines. No Lcc expression was detected. Moreover, the specific activity of these enzymes was generally higher in untreated pine than in the decay-resistant wood. This study contributes to the understanding of the role of fungal communities in wood decay and the impact of preservation treatments on the gene expression and activity of wood decay enzymes. © 2023, The Korean Society for Biotechnology and Bioengineering and Springer.