Initial Rhodonia placenta Gene Expression in Acetylated Wood: Group-Wise Upregulation of Non-Enzymatic Oxidative Wood Degradation Genes Depending on the Treatment Level

AbstractThe Fenton reaction is supposed to play a key role in the initial wood degradation by brown rot fungi. Wood was modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and glutaraldehyde (GA) to various weight percentage gains in order to study if these types of modifications are able to reduce wood degradation by Fenton reagent. Veneers modified with higher concentrations (1.2 and 2.0 mol l-1) of both chemicals exhibited minor losses in mass and tensile strength during treatment with Fenton reagent, which shows restrained oxidative degradation by hydroxyl radicals. The decomposition rate of H2O2was lower in the Fenton solutions containing modified veneers than in those containing unmodified controls. More CO2evolved in systems containing unmodified veneers than in systems with modified veneers, indicating that modification protected wood from mineralisation. The reason for the enhanced resistance of modified wood to the Fenton reaction is attributed to impeded diffusion of the reagent into the cell wall rather than to inhibition of the Fenton reaction itself. The results show that wood modification with DMDHEU and GA is able to restrain the degradation of wood by the Fenton reaction and can explain why modified wood is more resistant to brown rot decay.

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Comparative Transcriptomics During Brown Rot Decay in Three Fungi Reveals Strain-Specific Degradative Strategies and Responses to Wood Acetylation

Frontiers in Fungal Biology ◽

10.3389/ffunb.2021.701579 ◽

2021 ◽

Vol 2 ◽

Author(s):

Martina Kölle ◽

Maria Augusta Crivelente Horta ◽

J. Philipp Benz ◽

Annica Pilgård

Keyword(s):

Oxidative Degradation ◽

Brown Rot ◽

Gene Clusters ◽

Brown Rot Fungi ◽

Platform Chemicals ◽

Regulatory Circuits ◽

Detection And Identification ◽

Brown Rot Decay ◽

Underlying Mechanisms ◽

The Impact

Brown rot fungi degrade wood in a two-step process in which enzymatic hydrolysis is preceded by an oxidative degradation phase. While a detailed understanding of the molecular processes during brown rot decay is mandatory for being able to better protect wooden products from this type of degradation, the underlying mechanisms are still not fully understood. This is particularly true for wood that has been treated to increase its resistance against rot. In the present study, the two degradation phases were separated to study the impact of wood acetylation on the behavior of three brown rot fungi commonly used in wood durability testing. Transcriptomic data from two strains of Rhodonia placenta (FPRL280 and MAD-698) and Gloeophyllum trabeum were recorded to elucidate differences between the respective decay strategies. Clear differences were found between the two decay stages in all fungi. Moreover, strategies varied not only between species but also between the two strains of the same species. The responses to wood acetylation showed that decay is generally delayed and that parts of the process are attenuated. By hierarchical clustering, we could localize several transcription factors within gene clusters that were heavily affected by acetylation, especially in G. trabeum. The results suggest that regulatory circuits evolve rapidly and are probably the major cause behind the different decay strategies as observed even between the two strains of R. placenta. Identifying key genes in these processes can help in decay detection and identification of the fungi by biomarker selection, and also be informative for other fields, such as fiber modification by biocatalysts and the generation of biochemical platform chemicals for biorefinery applications.

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Samanlarda Biyolojik Muamelelerle Lignoselüloz Kompleksin Sindirilebilirliğinin Artırılması

Turkish Journal of Agriculture - Food Science and Technology ◽

10.24925/turjaf.v5i13.1704-1709.1522 ◽

2017 ◽

Vol 5 (13) ◽

pp. 1704

Author(s):

Aydan Atalar ◽

Nurcan Çetinkaya

Keyword(s):

Biological Treatment ◽

Hydrolytic Enzymes ◽

White Rot Fungi ◽

Ligninolytic Enzymes ◽

Brown Rot ◽

Soft Rot ◽

White Rot ◽

Enzyme Treatment ◽

Environmental Friendliness ◽

Brown Rot Fungi

The efforts to break down the lignocellulosic complex found in the cell wall of straws, besides digestible cellulose and hemicellulose by rumen fermentation, improvement of straw digestibility by the degradation of indigestible lignin fraction of complex by using of biotechnological methods is one of the focus areas of animal nutritionists in recent years. Biological method sare prefer redover other methods due to the environmental friendliness. In the biological treatment methods of lignocellulosic complex, biodiversity of bacteria, enzymes and fungi gives opportunity to select lignin degrading species. Mycobacterium, Arthrobacter and Flavobacterium genre bacteria are used to degrade lignin by bacterial treatment. Lignocellulolytic enzymes isolated from different varieties of fungi are used in enzyme treatment. There are 3 genres of fungus that are white, Brown and soft rot in fungal treatments. Brown rot fungi prefer ably attack cellulose and hemicelluloses, but not lignin. White rot fungi attack the lignin and break up lignol bonds and aromatic ring. White rot fungi break down polysaccharides with hydrolytic enzymes such as cellulase, xylanase, and lignin with oxidative ligninolytic enzymes such as lignin peroxidase and laccase. Because of the fact that the microorganisms that can break down the lignocellulosic materials are the fungi and the cost is low, the application of white rot fungi is possible. In this paper, improvement the lignocellulosic comlex digestibility of straw by biological treatment with the advantage of biodiversity is discussed.

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Stilbene impregnation retards brown-rot decay of Scots pine sapwood

Holzforschung ◽

10.1515/hf-2014-0251 ◽

2016 ◽

Vol 70 (3) ◽

pp. 261-266 ◽

Cited By ~ 13

Author(s):

Jinrong Lu ◽

Martti Venäläinen ◽

Riitta Julkunen-Tiitto ◽

Anni M. Harju

Keyword(s):

Scots Pine ◽

Fungal Growth ◽

Brown Rot ◽

Monomethyl Ether ◽

Wood Preservation ◽

High Concentration ◽

Brown Rot Fungi ◽

Decay Test ◽

Antifungal Efficiency ◽

Brown Rot Decay

Abstract Stilbenes are abundant in the heartwood of Scots pine (Pinus sylvestris L.) and are known to have strong antifungal efficiency. In this study, Scots pine sapwood blocks were impregnated with crude heartwood extract containing the stilbenes pinosylvin (PS) and the pinosylvin monomethyl ether (PSM). Impregnated blocks were submitted to brown-rot fungi, Coniophora puteana, Gloeophyllum trabeum, and Rhodonia (Poria) placenta, and fungal growth test and decay test were performed. Both tests showed that the impregnation with a high concentration of stilbenes (60 mg g-1 dry wood) significantly suppressed the growth of fungi and slowed down the decay process of wood blocks, especially in case of G. trabeum. However, chemical analysis showed that PS and PSM were degraded by all the three types of fungi, obviously via modification to resveratrol and methylresveratrol. Rhodonia placenta displayed the fastest rate of degradation. Thus, impregnation with biodegradable stilbenes could be a viable alternative for wood preservation only in service situations with low or transient risk of decay.

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Samanlarda Biyolojik Muamelelerle Lignoselüloz Kompleksin Sindirilebilirliğinin Artırılması

Turkish Journal of Agriculture - Food Science and Technology ◽

10.24925/turjaf.v5i13.1720-1725.1522 ◽

2017 ◽

Vol 5 (13) ◽

pp. 1720 ◽

Cited By ~ 1

Author(s):

Aydan Atalar ◽

Nurcan Çetinkaya

Keyword(s):

Biological Treatment ◽

Hydrolytic Enzymes ◽

White Rot Fungi ◽

Ligninolytic Enzymes ◽

Brown Rot ◽

Soft Rot ◽

White Rot ◽

Enzyme Treatment ◽

Environmental Friendliness ◽

Brown Rot Fungi

The efforts to break down the lignocellulosic complex found in the cell wall of straws, besides digestible cellulose and hemicellulose by rumen fermentation, improvement of straw digestibility by the degradation of indigestible lignin fraction of complex by using of biotechnological methods is one of the focus areas of animal nutritionists in recent years. Biological method sare prefer redover other methods due to the environmental friendliness. In the biological treatment methods of lignocellulosic complex, biodiversity of bacteria, enzymes and fungi gives opportunity to select lignin degrading species. Mycobacterium, Arthrobacter and Flavobacterium genre bacteria are used to degrade lignin by bacterial treatment. Lignocellulolytic enzymes isolated from different varieties of fungi are used in enzyme treatment. There are 3 genres of fungus that are white, Brown and soft rot in fungal treatments. Brown rot fungi prefer ably attack cellulose and hemicelluloses, but not lignin. White rot fungi attack the lignin and break up lignol bonds and aromatic ring. White rot fungi break down polysaccharides with hydrolytic enzymes such as cellulase, xylanase, and lignin with oxidative ligninolytic enzymes such as lignin peroxidase and laccase. Because of the fact that the microorganisms that can break down the lignocellulosic materials are the fungi and the cost is low, the application of white rot fungi is possible. In this paper, improvement the lignocellulosic comlex digestibility of straw by biological treatment with the advantage of biodiversity is discussed.

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Mode of action of brown rot decay resistance of thermally modified wood: resistance to Fenton’s reagent

Holzforschung ◽

10.1515/hf-2015-0141 ◽

2016 ◽

Vol 70 (7) ◽

pp. 691-697 ◽

Cited By ~ 13

Author(s):

Reza Hosseinpourpia ◽

Carsten Mai

Keyword(s):

Cell Wall ◽

Brown Rot ◽

Strength Loss ◽

Decay Resistance ◽

Fenton’S Reagent ◽

Fenton's Reagent ◽

Brown Rot Fungi ◽

Brown Rot Decay ◽

Wood Resistance ◽

Fe Ions

Abstract The resistance of heat treated (HT) wood to brown rot fungi has been investigated, while the role of the Fenton reaction (FR) in the initial phase of degradation was in focus. Micro-veneers made of Scots pine, were HT with various intensities and their mass losses (MLHT) were determined before soaking with a solution of Fenton’s reagent containing Fe ions and hydrogen peroxide. The mass loss of the veneers treated that way (MLFT), their tensile strength loss (TSLFT) and the H2O2 decomposition were observed. The MLFT, TSLFT, and H2O2 loss decreased with increasing MLHT of the veneers. Soaking of the veneers in acetate buffer containing only Fe without H2O2 revealed that the heat treatment (HT) strongly reduces the Fe uptake by the cell walls. FTIR spectroscopy indicated oxidation of the unmodified control veneers but did not reveal predominant decay of cell wall components; the HT veneers were not changed at all due to FR. It was concluded that the reason for the enhanced resistance of HT wood to FR is attributable to hindered diffusion of Fe ions into the wood cell wall.

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Mechanisms of wood degradation by brown-rot fungi: chelator-mediated cellulose degradation and binding of iron by cellulose

Journal of Biotechnology ◽

10.1016/s0168-1656(00)00430-2 ◽

2001 ◽

Vol 87 (1) ◽

pp. 43-57 ◽

Cited By ~ 104

Author(s):

G. Xu ◽

B. Goodell

Keyword(s):

Cellulose Degradation ◽

Brown Rot ◽

Wood Degradation ◽

Brown Rot Fungi

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Transcriptome analysis of the brown rot fungus Gloeophyllum trabeum during lignocellulose degradation

PLoS ONE ◽

10.1371/journal.pone.0243984 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0243984

Author(s):

Kiwamu Umezawa ◽

Mai Niikura ◽

Yuka Kojima ◽

Barry Goodell ◽

Makoto Yoshida

Keyword(s):

Degradation Mechanism ◽

Enzymatic Saccharification ◽

Japanese Cedar ◽

Brown Rot ◽

Terpene Synthase ◽

Lignocellulose Degradation ◽

Substrate Selectivity ◽

Gloeophyllum Trabeum ◽

Wood Degradation ◽

Brown Rot Fungi

Brown rot fungi have great potential in biorefinery wood conversion systems because they are the primary wood decomposers in coniferous forests and have an efficient lignocellulose degrading system. Their initial wood degradation mechanism is thought to consist of an oxidative radical-based system that acts sequentially with an enzymatic saccharification system, but the complete molecular mechanism of this system has not yet been elucidated. Some studies have shown that wood degradation mechanisms of brown rot fungi have diversity in their substrate selectivity. Gloeophyllum trabeum, one of the most studied brown rot species, has broad substrate selectivity and even can degrade some grasses. However, the basis for this broad substrate specificity is poorly understood. In this study, we performed RNA-seq analyses on G. trabeum grown on media containing glucose, cellulose, or Japanese cedar (Cryptomeria japonica) as the sole carbon source. Comparison to the gene expression on glucose, 1,129 genes were upregulated on cellulose and 1,516 genes were upregulated on cedar. Carbohydrate Active enZyme (CAZyme) genes upregulated on cellulose and cedar media by G. trabeum included glycoside hyrolase family 12 (GH12), GH131, carbohydrate esterase family 1 (CE1), auxiliary activities family 3 subfamily 1 (AA3_1), AA3_2, AA3_4 and AA9, which is a newly reported expression pattern for brown rot fungi. The upregulation of both terpene synthase and cytochrome P450 genes on cedar media suggests the potential importance of these gene products in the production of secondary metabolites associated with the chelator-mediated Fenton reaction. These results provide new insights into the inherent wood degradation mechanism of G. trabeum and the diversity of brown rot mechanisms.

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Distinct Growth and Secretome Strategies for Two Taxonomically Divergent Brown Rot Fungi

Applied and Environmental Microbiology ◽

10.1128/aem.02987-16 ◽

2017 ◽

Vol 83 (7) ◽

Cited By ~ 31

Author(s):

Gerald N. Presley ◽

Jonathan S. Schilling

Keyword(s):

Glycoside Hydrolase ◽

Hydrolytic Enzymes ◽

Brown Rot ◽

Life History Strategies ◽

Growth Strategies ◽

Content Type ◽

Postia Placenta ◽

Brown Rot Fungi ◽

Versus Protein ◽

Step Mechanism

ABSTRACT Brown rot fungi are wood-degrading fungi that employ both oxidative and hydrolytic mechanisms to degrade wood. Hydroxyl radicals that facilitate the oxidative component are powerful nonselective oxidants and are incompatible with hydrolytic enzymes unless they are spatially segregated in wood. Differential gene expression has been implicated in the segregation of these reactions in Postia placenta, but it is unclear if this two-step mechanism varies in other brown rot fungi with different traits and life history strategies that occupy different niches in nature. We employed proteomics to analyze a progression of wood decay on thin wafers, using brown rot fungi with significant taxonomic and niche distances: Serpula lacrymans (Boletales; “dry rot” lumber decay) and Gloeophyllum trabeum (order Gloeophyllales; slash, downed wood). Both fungi produced greater oxidoreductase diversity upon wood colonization and greater glycoside hydrolase activity later, consistent with a two-step mechanism. The two fungi invested very differently, however, in terms of growth (infrastructure) versus protein secretion (resource capture), with the ergosterol/extracted protein ratio being 7-fold higher with S. lacrymans than with G. trabeum. In line with the native substrate associations of these fungi, hemicellulase-specific activities were dominated by mannanase in S. lacrymans and by xylanase in G. trabeum. Consistent with previous observations, S. lacrymans did not produce glycoside hydrolase 6 (GH6) cellobiohydrolases (CBHs) in this study, despite taxonomically belonging to the order Boletales, which is distinguished among brown rot fungi by having CBH genes. This work suggests that distantly related brown rot fungi employ staggered mechanisms to degrade wood, but the underlying strategies vary among taxa. IMPORTANCE Wood-degrading fungi are important in forest nutrient cycling and offer promise in biotechnological applications. Brown rot fungi are unique among these fungi in that they use a nonenzymatic oxidative pretreatment before enzymatic carbohydrate hydrolysis, enabling selective removal of carbohydrates from lignin. This capacity has independently evolved multiple times, but it is unclear if different mechanisms underpin similar outcomes. Here, we grew fungi directionally on wood wafers and we found similar two-step mechanisms in taxonomically divergent brown rot fungi. The results, however, revealed strikingly different growth strategies, with S. lacrymans investing more in biomass production than secretion of proteins and G. trabeum showing the opposite pattern, with a high diversity of uncharacterized proteins. The “simplified” S. lacrymans secretomic system could help narrow gene targets central to oxidative brown rot pretreatments, and a comparison of its distinctions with G. trabeum and other brown rot fungi (e.g., Postia placenta) might offer similar traction in noncatabolic genes.

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