Search

Wood-decaying fungi tend to have characteristic substrate ranges that partly define their ecological niche. Fomitopsis pinicola is a brown rot species of Polyporales that is reported on 82 species of softwoods and 42 species of hardwoods. We analyzed gene expression levels of F. pinicola from submerged cultures with ground wood powder (sampled at 5 days) or solid wood wafers (sampled at 10 and 30 days), using aspen, pine, and spruce substrates (aspen was used only in submerged cultures). Fomitopsis pinicola expressed similar sets of wood-degrading enzymes typical of brown rot fungi across all culture conditions and time points. Nevertheless, differential gene expression was observed across all pairwise comparisons of substrates and time points. Genes exhibiting differential expression encode diverse enzymes with known or potential function in brown rot decay, including laccase, benzoquinone reductase, aryl alcohol oxidase, cytochrome P450s, and various glycoside hydrolases. Comparing transcriptomes from submerged cultures and wood wafers, we found that culture conditions had a greater impact on global expression profiles than substrate wood species. These findings highlight the need for standardization of culture conditions in studies of gene expression in wood-decaying fungi.IMPORTANCE All species of wood-decaying fungi occur on a characteristic range of substrates (host plants), which may be broad or narrow. Understanding the mechanisms that allow fungi to grow on particular substrates is important for both fungal ecology and applied uses of different feedstocks in industrial processes. We grew the wood-decaying polypore Fomitopsis pinicola on three different wood species—aspen, pine, and spruce—under various culture conditions. We found that F. pinicola is able to modify gene expression (transcription levels) across different substrate species and culture conditions. Many of the genes involved encode enzymes with known or predicted functions in wood decay. This study provides clues to how wood-decaying fungi may adjust their arsenal of decay enzymes to accommodate different host substrates.

Several bacterial species can remove wood extractives from wood chips prior to the paper making process. Southern yellow pine chips lost 40% of their wood extractives over a 14-day period when treated with Pseudomonas fluorescens, Pseudomonas sp., Xanthomonas campestris, and Serratia marcescens. The treated wood was not stained during the process.

Phlebiopsis gigantea was inoculated on Pinus resinosa and Pinus gigantea pine logs to determine the efficiency of the saprophytic fungus in the biological processing of pine logs into paper and pulp. Inoculation of logs with Phlebiopsis gigantea after cutting induced extensive colonization which induced pitch degradation and increased cell wall porosity. The effects of the white rot fungus on pine logs also improved pulping efficiency.

Secretome and transcriptome analyses were performed on both wood decay fungi cultured for 5 days in media containing ball-milled aspen or glucose as the sole carbon source to understand the number, structure, and regulation of genes involved in lignocellulosic cell wall attack in Postia placenta and d. P. chrysosporium employs an array of extracellular glycosyl hydrolases to simultaneously attack cellulose and hemicelluloses while P. placenta secretes an array of hemicellulases but few potential cellulases under the same condition and both the species showed distinct expression patterns for oxidoreductase-encoding genes.

The white rot basidiomycete Phanerochaete chrysoporium generates an array of nonspecific extracellular enzymes pertaining to be involved in ligning degradation along with lignin peroxidases, mangenese peroxidases and the [H.sub.2O.sub.2]-generating copper radical oxidase, glyoxal oxidase (GLX). Preliminary analysis of the Phanerochaete chrysoporium draft genome revealed six sequences with significant similarity to GLX designated cro1 through cro6.

An investigation carried out to evaluate wood decay present at the three historic huts in the Ross Sea region, identify fungi isolated from the decayed wood by using internal transcribed spacer (ITS) sequences of ribosomal DNA (rDNA), to determine where these fungi are located in the historic huts, and evaluate their decay potential in laboratory studies, is presented. The results of the study may provide information crucial to conservators for preservation of these historic sites as well as new information on decay fungi and elucidate the type and extent of degradation that has occurred.