Cytochemical Localization of Hydrogen Peroxide Production during Wood Decay by Brown-Rot Fungi Tyromyces palustris and Coniophora puteana

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Yoon Soo Kim ◽  
Seung Gon Wi ◽  
Kwang Ho Lee ◽  
Adya P. Singh
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Walls ◽  
Wood Decay ◽  
Brown Rot ◽  
Cerium Chloride ◽  
Cytochemical Localization ◽  
Coniophora Puteana ◽  
Brown Rot Fungi ◽  
Transmission Electron ◽  
Early Degradation

Summary It is not definitively known whether or not the production of extracellular hydrogen peroxide (H2O2) is a universal characteristic of brown-rot fungi. Cytochemical localization of H2O2 was tested in two brown-rot fungi, Tyromyces palustris and Coniophora puteana, by staining with cerium chloride. Transmission electron microscopy (TEM) showed the deposition of cerium perhydroxide within the fungal hyphae as well as wood cell walls affected by brown-rot fungi. TEM work indicated that extracellular H2O2 was present in brown-rot fungi and that H2O2 from brown-rot fungi diffused into the wood cell walls in the early stages of decay. The present work strongly suggests that H2O2 plays an important role in the early degradation of cellulose by brown-rot fungi. The usefulness of this technique for localizing H2O2 at high resolution with minimal nonspecific deposition is also discussed.

scholarly journals Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungusPostia placenta

2016 ◽  
Vol 113 (39) ◽  
pp. 10968-10973 ◽  
Author(s):  
Jiwei Zhang ◽  
Gerald N. Presley ◽  
Kenneth E. Hammel ◽  
Jae-San Ryu ◽  
Jon R. Menke ◽  
...  
Keyword(s):  
Cell Walls ◽  
Plant Biomass ◽  
Wood Decay ◽  
Brown Rot ◽  
Glycoside Hydrolases ◽  
Ros Generation ◽  
Rna Seq ◽  
Postia Placenta ◽  
Brown Rot Fungi ◽  
Whole Transcriptome

Wood-degrading brown rot fungi are essential recyclers of plant biomass in forest ecosystems. Their efficient cellulolytic systems, which have potential biotechnological applications, apparently depend on a combination of two mechanisms: lignocellulose oxidation (LOX) by reactive oxygen species (ROS) and polysaccharide hydrolysis by a limited set of glycoside hydrolases (GHs). Given that ROS are strongly oxidizing and nonselective, these two steps are likely segregated. A common hypothesis has been that brown rot fungi use a concentration gradient of chelated metal ions to confine ROS generation inside wood cell walls before enzymes can infiltrate. We examined an alternative: that LOX components involved in ROS production are differentially expressed by brown rot fungi ahead of GH components. We used spatial mapping to resolve a temporal sequence inPostia placenta, sectioning thin wood wafers colonized directionally. Among sections, we measured gene expression by whole-transcriptome shotgun sequencing (RNA-seq) and assayed relevant enzyme activities. We found a marked pattern of LOX up-regulation in a narrow (5-mm, 48-h) zone at the hyphal front, which included many genes likely involved in ROS generation. Up-regulation of GH5 endoglucanases and many other GHs clearly occurred later, behind the hyphal front, with the notable exceptions of two likely expansins and a GH28 pectinase. Our results support a staggered mechanism for brown rot that is controlled by differential expression rather than microenvironmental gradients. This mechanism likely results in an oxidative pretreatment of lignocellulose, possibly facilitated by expansin- and pectinase-assisted cell wall swelling, before cellulases and hemicellulases are deployed for polysaccharide depolymerization.

scholarly journals A Fungal Secretome Adapted for Stress Enabled a Radical Wood Decay Mechanism

mBio ◽  
2021 ◽  
Author(s):  
Jesus Castaño ◽  
Jiwei Zhang ◽  
Mowei Zhou ◽  
Chia-Feng Tsai ◽  
Joon Yong Lee ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Walls ◽  
Critical Role ◽  
Wood Decay ◽  
Brown Rot ◽  
Oxygen Species ◽  
Decay Mechanism ◽  
Brown Rot Fungi ◽  
Carbon Recycling ◽  
Fungal Secretome

Brown rot fungi play a critical role in carbon recycling and are of industrial interest. These fungi typically use reactive oxygen species (ROS) to indiscriminately “loosen” wood cell walls at the outset of decay.

Variation in germination percentage of basidiospores collected successively from wood decay fungi in culture

1983 ◽  
Vol 61 (1) ◽  
pp. 171-173 ◽  
Author(s):  
E. L. Schmidt ◽  
D. W. French
Keyword(s):  
Spore Germination ◽  
White Rot Fungi ◽  
Wood Decay ◽  
Brown Rot ◽  
Germination Percentage ◽  
White Rot ◽  
Malt Extract ◽  
Decay Fungi ◽  
Brown Rot Fungi ◽  
Wood Decay Fungi

Successive collections of basidiospores, produced in culture from the same hymenial areas of four species of wood decay fungi, were tested for spore germination percentage on malt extract agar under controlled conditions. Spores from white rot fungi retained high germination levels after 5 weeks of spore production, but germination averages for brown rot fungi decreased by more than 50%. Such variation should be considered in wood pathology research using spore germination bioassay.

Characterisation of a Soft Rot-Like Decay Pattern Caused by Coniophora puteana (Schum.) Karst. in Sapelli Wood (Entandrophragma cylindricum Sprague)

Holzforschung ◽  
2001 ◽  
Vol 55 (6) ◽  
pp. 573-578 ◽  
Author(s):  
G. Kleist ◽  
U. Schmitt
Keyword(s):  
Lignin Degradation ◽  
Uv Spectroscopy ◽  
Brown Rot ◽  
Soft Rot ◽  
High Moisture ◽  
Coniophora Puteana ◽  
Transmission Electron ◽  
Brown Rot Fungus ◽  
Decay Pattern ◽  
Microfibrillar Angle

Summary The decay patterns of brown and soft rot fungi in Sapelli wood (Entandrophragma cylindricum Sprague), with respect to natural durability, were examined by light and transmission electron microscopy as well as UV spectroscopy. Analyses revealed that the typical brown rot fungus Coniophora puteana can cause a soft rot-like decay in the sapwood of Sapelli at high moisture contents of approx. 100%. In accordance with the decay pattern of the typical soft rot fungus Chaetomium globosum, the hyphae of C. puteana penetrated the S2 wall of fibres and formed characteristic rhomboidal cavities orientated parallel to the microfibrillar angle. However, these cavities were larger in diameter (3.9 μm ± 0.9) than those formed by C. globosum (2.1 μm ± 0.5) and with a distinct interspace between the hyphae and surrounding walls. Hyphae of C. globosum were directly attached to the undecayed secondary wall. No lignin degradation for both fungi in close vicinity to the cavities was observed, as evidenced by UV spectroscopy. The inclusion of microscopy for definitive decay type identification is recommended.

Comparative Morphology of Early Stages of Brown-Rot Wood Decay

IAWA Journal ◽  
1993 ◽  
Vol 14 (2) ◽  
pp. 127-138 ◽  
Author(s):  
W. Wayne Wilcox
Keyword(s):  
Wood Decay ◽  
Brown Rot ◽  
Comparative Morphology ◽  
Diagnostic Feature ◽  
Postia Placenta ◽  
Brown Rot Fungi ◽  
Early Stages ◽  
Poria Placenta ◽  
White Fir ◽  
Early Progression

Early stages of decay by two brown-rot fungi in two woods were studied by light and scanning electron microscopy. The earliest diagnostic feature to appear was hyphae in the earlywood lumina. The earliest effect on cell walls was the loss of birefringence in the earlywood; Poria placenta (syn. Postia placenta) caused this loss at the earliest stage of decay observed, in both Douglas-fir and white fir, while Gloeophyllum trabeum caused significant weight loss before loss of birefringence was visible. Attack on the latewood progressed from the earlywood, and was different in pattern among the wood/fungus combinations. Hyphal and bore hole diameter increased throughout the early progression of decay and would be useful in evaluating the stage of decay, if the starting diameter of hyphae could be determined. Separation between cells was not observed until moderate stages of decay and, therefore, was not useful in diagnosing early stages of decay.

Osmium Staining Fails to Detect Early Cell Wall Damage in Brown Rot Wood Decay

IAWA Journal ◽  
1994 ◽  
Vol 15 (2) ◽  
pp. 133-136
Author(s):  
W. Wayne Wilcox
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Walls ◽  
Osmium Tetroxide ◽  
Wood Decay ◽  
Brown Rot ◽  
X Ray ◽  
Polarised Light ◽  
Early Manifestation ◽  
Scanning Electron

Loss of cell wall birefringence under polarised light in the light microscope is an important diagnostic characteristic for early stages of brown rot wood decay not available with the scanning electron microscope (SEM). Osmium tetroxide staining was explored as a means of visualising this early manifestation of decay in the SEM, but proved unsuccessful as X-ray spectroscopy indicated that osmium was evenly distributed across both distorted and non-distorted cell walls.

scholarly journals Resistance of the S1 layer in kempas heartwood fibers to soft rot decay

IAWA Journal ◽  
2018 ◽  
Vol 39 (1) ◽  
pp. 37-42
Author(s):  
Adya P. Singh ◽  
Andrew H.H. Wong ◽  
Yoon Soo Kim ◽  
Seung Gon Wi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Walls ◽  
Middle Lamella ◽  
Wood Decay ◽  
Soft Rot ◽  
Normal Wood ◽  
Fibre Cell ◽  
Utility Pole ◽  
Transmission Electron

Naturally durable heartwoods, where available, continue to be used as support structures in environments considered hazardous, particularly in ground contact. However, durability of heartwoods against wood decay microorganisms varies. Therefore, it is important to evaluate heartwood products for their in-service performance in order to maximise benefits derived from this valuable natural resource of limited supply. In the work presented, wood pieces from a kempas (Koompassia malaccensis) utility pole that had been placed in service in an acidic soil in Malaysia, and in time had softened at the ground-line position, were examined by light and transmission electron microscopy to evaluate the cause of deterioration.Light microscopy (LM) provided evidence of extensive attack on fibre cell walls by cavity-producing soft rot fungi. Transmission electron microscopy (TEM) revealed in greater detail the distribution and micromorphologies of cavities as well as their relationships to the fine structure of fibre cell walls, which consisted of a highly electron dense middle lamella, a moderately dense S1 layer and a multilamellar S2 layer with variable densities, reflecting differences in lignin concentration. The resistance of the moderately dense S1 layer to soft rot was a feature of particular interest and is the main focus of the work presented. The resistance appeared to be correlated with high lignification of the outermost region of the S2 wall, interfacing with the S1 layer, an unusual cell wall feature not previously described for normal wood.

scholarly journals Distribution, Characteristics, and Regulatory Potential of Long Noncoding RNAs in Brown-Rot Fungi

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Alessandra Borgognone ◽  
Walter Sanseverino ◽  
Riccardo Aiese Cigliano ◽  
Raúl Castanera
Keyword(s):  
Noncoding Rnas ◽  
Gc Content ◽  
Brown Rot ◽  
Long Noncoding Rnas ◽  
Upstream Gene ◽  
Coniophora Puteana ◽  
Brown Rot Fungi ◽  
Serpula Lacrymans ◽  
Genomic Regions

Long noncoding RNAs have been thoroughly studied in plants, animals, and yeasts, where they play important roles as regulators of transcription. Nevertheless, almost nothing is known about their presence and characteristics in filamentous fungi, especially in basidiomycetes. In the present study, we have carried out an exhaustive annotation and characterization of lncRNAs in two lignin degrader basidiomycetes, Coniophora puteana and Serpula lacrymans. We identified 2,712 putative lncRNAs in the former and 2,242 in the latter, mainly originating from intergenic locations of transposon-sparse genomic regions. The lncRNA length, GC content, expression levels, and stability of the secondary structure differ from coding transcripts but are similar in these two species and resemble that of other eukaryotes. Nevertheless, they lack sequence conservation. Also, we found that lncRNAs are transcriptionally regulated in the same proportion as genes when the fungus actively decomposes soil organic matter. Finally, up to 7% of the upstream gene regions of Coniophora puteana and Serpula lacrymans are transcribed and produce lncRNAs. The study of expression trends in these gene-lncRNA pairs uncovered groups with similar and opposite transcriptional profiles which may be the result of cis-transcriptional regulation.

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