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

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

Forests ◽

10.3390/f10121117 ◽

2019 ◽

Vol 10 (12) ◽

pp. 1117 ◽

Cited By ~ 4

Author(s):

Martina Kölle ◽

Rebecka Ringman ◽

Annica Pilgård

Keyword(s):

Hydrolytic Enzymes ◽

Oxidative Degradation ◽

Brown Rot ◽

Treatment Level ◽

Wood Degradation ◽

Weight Percentage ◽

Brown Rot Fungi ◽

Number Of Genes ◽

Brown Rot Decay ◽

Underlying Mechanisms

Acetylation has been shown to delay fungal decay, but the underlying mechanisms are poorly understood. Brown-rot fungi, such as Rhodonia placenta (Fr.) Niemelä, K.H. Larss. & Schigel, degrade wood in two steps, i.e., oxidative depolymerization followed by secretion of hydrolytic enzymes. Since separating the two degradation steps has been proven challenging, a new sample design was applied to the task. The aim of this study was to compare the expression of 10 genes during the initial decay phase in wood and wood acetylated to three different weight percentage gains (WPG). The results showed that not all genes thought to play a role in initiating brown-rot decay are upregulated. Furthermore, the results indicate that R. placenta upregulates an increasing number of genes involved in the oxidative degradation phase with increasing WPG.

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Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

Holzforschung ◽

10.1515/hf-2014-0067 ◽

2015 ◽

Vol 69 (2) ◽

pp. 153-161 ◽

Cited By ~ 5

Author(s):

Yanjun Xie ◽

Zefang Xiao ◽

Carsten Mai

Keyword(s):

Fenton Reaction ◽

Oxidative Degradation ◽

Brown Rot ◽

Fenton Reagent ◽

Wood Degradation ◽

Weight Percentage ◽

Brown Rot Fungi ◽

Minor Losses ◽

Brown Rot Decay ◽

Modified Wood

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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Unraveling the natural durability of wood: revealing the impact of decay-influencing characteristics other than fungicidal components

Holzforschung ◽

10.1515/hf-2020-0109 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Liselotte De Ligne ◽

Jan Van den Bulcke ◽

Jan M. Baetens ◽

Bernard De Baets ◽

Gang Wang ◽

...

Keyword(s):

Wood Species ◽

Prunus Avium ◽

Brown Rot ◽

Natural Durability ◽

Anatomical Features ◽

Brown Rot Fungi ◽

Material Characteristics ◽

The One ◽

Block Test ◽

The Impact

AbstractThe effect of fungicidal components in wood has been known for ages, yet there is no method to assess the impact of such components on the durability of a wood species, as compared to other material characteristics that influence decay. In this paper, the importance of fungicidal effects on the natural durability of 10 wood species is assessed in relation to other decay-influencing factors with a new test, the so-called ‘paste test’. By comparing results from this test with the ‘mini-block test’, on both heartwood and leached sapwood, insight is gained into the significance of fungicidal components on the one hand and other material characteristics on the other hand. The durability of species such as Prunus avium was attributed mainly to fungicidal components. For species such as Pterocarpus soyauxii, durability seemed to be an effect of both fungicidal components and moisture-regulating components, while the latter seemed to be of main importance in regulating the decay of Aucoumea klaineana and Entandrophragma cylindricum. Wood-anatomical features, such as the parenchyma content (in case of brown rot fungi) and the vessel-fiber ratio, possibly affect degradation as well. This work shows that fungicidal components are not always of major importance for the durability of a wood species. The authors hereby emphasize the importance of moisture-regulating components and wood anatomy on the durability of wood.

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Effects of epyxilous fungus Laetiporus sulphureus (Bull. ex Fr.) murrill on the deccomposition of oak wood

Sustainable Forestry: Collection ◽

10.5937/sustfor1775021m ◽

2017 ◽

pp. 21-30

Author(s):

Miroslava Marković ◽

Snežana Rajković ◽

Mara Tabaković-Tošić ◽

Marija Milosavljević

Keyword(s):

Regression Line ◽

Brown Rot ◽

Wood Properties ◽

Quercus Petraea ◽

Modulus Of Rupture ◽

Oak Wood ◽

Brown Rot Fungi ◽

Static Modulus ◽

Laetiporus Sulphureus ◽

The Impact

Testing samples were collected from the medulla of healthy oak trees in Eastern Serbia, from the association of Quercetum montanum. Over the periods of 2, 4 and 6 months the wood samples were exposed to influence of the mycelia of the fungus causing cubical brown rot on oak. Given that static modulus of rupture provides the quickest and clearest way to observe destruction caused by epixylous fungi, this paper researched the decrease in modulus of rupture of Sessile oak wood due to influence of causers of cubical brown rot. The samples have been exposed to the impact of the mycelia of the brown rot fungus on oak tree Laetiporus sulphureus (Bull. ex Fr.) Murrill (Sulphur Polypore). Effect of to the impact of the brown rot fungi was investigated, in decrease of static modulus of rupture Quercus petraea agg. The static modulus of rupture caused by L. sulphureus after 2, 4 and 6 months decreased in comparison with initial ones (100%) and reached 91.73, 75.17 and 63.25%. By using correlation analyses of Q. petraea agg. static modulus of rupture - ss (dependent variable) of fungi time influence (T-independent variable) strong correlation between variables was established, and regression equation is: ss= 151.514 ± 30,657 √ T The regression line obtained through data processing opened the possibility to prognosticate the changes of wood properties in certain time periods of the effect of the fungus under the unchanged external conditions, which is significant for practical purposes in terms of taking protective measures and wood usability.

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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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Effects of white rot and brown rot decay on the drilling resistance measurements in wood

Holzforschung ◽

10.1515/hf-2017-0204 ◽

2018 ◽

Vol 72 (10) ◽

pp. 905-913 ◽

Cited By ~ 3

Author(s):

Evgenii Sharapov ◽

Christian Brischke ◽

Holger Militz ◽

Elena Smirnova

Keyword(s):

Scots Pine ◽

Free Water ◽

Brown Rot ◽

European Beech ◽

White Rot ◽

Drilling Tool ◽

Significant Difference ◽

Brown Rot Decay ◽

Drilling Resistance ◽

The Impact

AbstractAn IML-RESI PD 400 drilling tool and a standard spade drill bit (IML System GmbH, Wiesloch, Germany) were used to study the impact of white and brown rot decay on drilling resistance (DR) measurements in wood. In total, 720 drillings were made in specimens of Scots pine (Pinus sylvestrisL.) heartwood and sapwood, European beech (Fagus sylvaticaL.) and English oak (Quercus roburL.), which were decayed byConiophora puteanaandTrametes versicolor. Drillings were made with specimens conditioned in normal climate (20°C/65% RH) and with specimens vacuum-impregnated in water. DR and feeding force (FF) were negatively correlated with mass loss (ML) due to fungal decay. The intensity of reduction was higher for DR than for FF with increasing ML for all decay types and moisture contents (MCs). A significant difference (at 95% confidence level) in DR was found between decay types using water-saturated (WS) Scots pine specimens (3–35% ML). In most cases, DR revealed a higher predictive power of the models for ML prediction than FF. Free water in decayed specimens significantly reduced the DR and FF. Hence, the effect of ML on DR and FF of decayed and WS wood was less prominent.

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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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Influence of Soil Characteristics on Wood Biodeterioration by Brown Rot Fungi

Applied Sciences ◽

10.3390/app10248837 ◽

2020 ◽

Vol 10 (24) ◽

pp. 8837

Author(s):

Javier Ribera ◽

Elisabeth Michel ◽

Francis W. M. R. Schwarze

Keyword(s):

Humic Acid ◽

Wood Decay ◽

Brown Rot ◽

Soil Conditions ◽

Wood Preservatives ◽

Premature Failure ◽

Brown Rot Fungi ◽

Weight Losses ◽

The Impact ◽

Impregnated Wood

Soil conditions can directly influence the inoculum potential of wood decay fungi, which is likely to be a major factor in the premature failure of utility poles across Europe. The objective of our study was to assess the influence of soil pH, humic acid and iron on wood decay. For this purpose, we incubated Fe-impregnated wood specimens on artificial medium to evaluate the influence of the metal on the activity of brown rot fungi. Moreover, the impact of Cu-leaching from impregnated wood specimens that were exposed to humic acid solutions was measured. In addition, weight losses caused by brown rot fungi in impregnated wood pole segments and stiffness (Young’s modulus of Elasticity) of Cu-impregnated wood specimens were quantified. The pH measurements showed that the soil samples were slightly acid (pH = 6.7 ± 0.7). In comparison to non-impregnated controls, the Fe-impregnated samples significantly increased weight losses by brown rot fungi (>30–40%). In the presence of humic acid the release of copper from chromium-free wood preservatives (up to 143.34 mg L−1) was enhanced. Weight losses in impregnated wood segments by brown rot fungi ranged from 5.3 to 20.4%. The recorded reduction in stiffness by brown rot fungi ranged from approximately 3.96 to 55.52% for Cu-impregnated wood specimens after 12 weeks. Our study shows that the pH, humic acid, iron content and selected wood preservatives greatly influence susceptibility of impregnated wood to brown rot fungi during ground contact.

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Asymmetrical Attribution of Performance in China

Asian Survey ◽

10.1525/as.2020.60.5.978 ◽

2020 ◽

Vol 60 (5) ◽

pp. 978-1003

Author(s):

Jacqueline Chen Chen ◽

Jun Xiang

Keyword(s):

Economic Development ◽

Local Governments ◽

Central Government ◽

Cultural Theory ◽

Political Trust ◽

Mediation Model ◽

Multilevel Mediation ◽

Dual Pathway ◽

Underlying Mechanisms ◽

The Impact

Existing studies of the impact of economic development on political trust in China have two major gaps: they fail to explain how economic development contributes to the hierarchical trust pattern, and they do not pay enough attention to the underlying mechanisms. In light of cultural theory and political control theory, we propose adapting performance theory into a theory of “asymmetrical attribution of performance” to better illuminate the case of China. This adapted theory leads to dual pathway theses: expectation fulfillment and local blaming. Using a multilevel mediation model, we show that expectation fulfillment mainly upholds trust in the central government, whereas local blaming undermines trust in local governments. We also uncover a rural–urban distinction in the dual pathway, revealing that both theses are more salient among rural Chinese.

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Audio-Based Drone Detection and Identification Using Deep Learning Techniques with Dataset Enhancement through Generative Adversarial Networks

Sensors ◽

10.3390/s21154953 ◽

2021 ◽

Vol 21 (15) ◽

pp. 4953

Author(s):

Sara Al-Emadi ◽

Abdulla Al-Ali ◽

Abdulaziz Al-Ali

Keyword(s):

Neural Network ◽

Deep Learning ◽

Recurrent Neural Network ◽

Learning Algorithms ◽

Generative Adversarial Networks ◽

Generative Adversarial Network ◽

Adversarial Networks ◽

Detection And Identification ◽

Learning Techniques ◽

The Impact

Drones are becoming increasingly popular not only for recreational purposes but in day-to-day applications in engineering, medicine, logistics, security and others. In addition to their useful applications, an alarming concern in regard to the physical infrastructure security, safety and privacy has arisen due to the potential of their use in malicious activities. To address this problem, we propose a novel solution that automates the drone detection and identification processes using a drone’s acoustic features with different deep learning algorithms. However, the lack of acoustic drone datasets hinders the ability to implement an effective solution. In this paper, we aim to fill this gap by introducing a hybrid drone acoustic dataset composed of recorded drone audio clips and artificially generated drone audio samples using a state-of-the-art deep learning technique known as the Generative Adversarial Network. Furthermore, we examine the effectiveness of using drone audio with different deep learning algorithms, namely, the Convolutional Neural Network, the Recurrent Neural Network and the Convolutional Recurrent Neural Network in drone detection and identification. Moreover, we investigate the impact of our proposed hybrid dataset in drone detection. Our findings prove the advantage of using deep learning techniques for drone detection and identification while confirming our hypothesis on the benefits of using the Generative Adversarial Networks to generate real-like drone audio clips with an aim of enhancing the detection of new and unfamiliar drones.

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