The Persistence of Decaying Wood in the Humus Layers of Northern Forests

McFee, W. W.; Stone, E. L.

doi:10.2136/sssaj1966.03615995003000040032x

Cited by 87 publications

(64 citation statements)

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“…Although here we are concerned with Douglas-fir, neither decaying wood nor research data are unique to forests of the Pacific Northwest. McFee and Stone (1966) observed that decaying wood persisted for more than 100 years in New York, and Falinski (1978) noted substantial accumulations of coarse woody debris in an old-growth forest in Poland. Appreciable accumulations of fallen trees also occur in the temperate forests of the Andes of central Chile, in the course of long-term forest succession (Veblen 1979).…”

Section: Insect Galleries and Frassmentioning

confidence: 99%

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The seen and unseen world of the fallen tree.

Maser¹,

Trappe²

1984

199

125

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Section: Insect Galleries and Frassmentioning

confidence: 99%

“…That which has disappeared, however, is not all lost through metabolism of decomposers. Much of it merges into the humus or becomes incorporated into the soil profile (Denny and Goodlett 1956;others 1978, 1979b;McFee and Stone 1966). The importance of internal surface areas is that, through such surfaces, a fallen tree interacts with its environment.…”

mentioning

confidence: 99%

The seen and unseen world of the fallen tree.

Maser¹,

Trappe²

1984

199

125

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“…Brown rot basidiomycetes cause a highly destructive type of wood decay and are important lignocellulose recyclers in forest ecosystems (7,19,32). During early brown rot, cellulose is rapidly oxidized and depolymerized, even though the porosity of sound wood is too low for enzymes such as cellulases to penetrate (6).…”

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confidence: 99%

Differential Stress-Induced Regulation of Two Quinone Reductases in the Brown Rot BasidiomyceteGloeophyllum trabeum

Cohen

Suzuki

Hammel

2004

Appl Environ Microbiol

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Quinone reductases (QRDs) have two important functions in the basidiomycete Gloeophyllum trabeum, which causes brown rot of wood. First, a QRD is required to generate biodegradative hydroxyl radicals via redox cycling between two G. trabeum extracellular metabolites, 2,5-dimethoxyhydroquinone (2,5-DMHQ) and 2,5-dimethoxy-1,4-benzoquinone (2,5-DMBQ). Second, because 2,5-DMBQ is cytotoxic and 2,5-DMHQ is not, a QRD is needed to maintain the intracellular pool of these metabolites in the reduced form. Given their importance in G. trabeum metabolism, QRDs could prove useful targets for new wood preservatives. We have identified two G. trabeum genes, each existing in two closely related, perhaps allelic variants, that encode QRDs in the flavodoxin family. Past work with QRD1 and heterologous expression of QRD2 in this study confirmed that both genes encode NADH-dependent, flavin-containing QRDs. Real-time reverse transcription PCR analyses of liquid-and wood-grown cultures showed that qrd1 expression was maximal during secondary metabolism, coincided with the production of 2,5-DMBQ, and was moderately up-regulated by chemical stressors such as quinones. By contrast, qrd2 expression was maximal during fungal growth when 2,5-DMBQ levels were low, yet was markedly up-regulated by chemical stress or heat shock. The total QRD activity in lysates of G. trabeum mycelium was significantly enhanced by induction beforehand with a cytotoxic quinone. The promoter of qrd2 contains likely antioxidant, xenobiotic, and heat shock elements, absent in qrd1, that probably explain the greater response of qrd2 transcription to stress. We conclude from these results that QRD1 is the enzyme G. trabeum routinely uses to detoxify quinones during incipient wood decay and that it could also drive the biodegradative quinone redox cycle. However, QRD2 assumes a more important role when the mycelium is stressed.

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“…The basidiomycetes that cause brown rot of wood are major recyclers of lignocellulose in terrestrial ecosystems and also cause the most destructive type of decay found in wooden structures (7,17,22). Although much remains unknown about their biodegradative mechanisms, there is growing evidence (2,8,11,13,21) that these fungi produce extracellular hydroxyl radicals (…”

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confidence: 99%

An NADH:Quinone Oxidoreductase Active during Biodegradation by the Brown-Rot Basidiomycete Gloeophyllum trabeum

Jensen

Ryan

Wymelenberg

et al. 2002

Appl Environ Microbiol

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The brown-rot basidiomycete Gloeophyllum trabeum uses a quinone redox cycle to generate extracellular Fenton reagent, a key component of the biodegradative system expressed by this highly destructive wood decay fungus. The hitherto uncharacterized quinone reductase that drives this cycle is a potential target for inhibitors of wood decay. We have identified the major quinone reductase expressed by G. trabeum under conditions that elicit high levels of quinone redox cycling. The enzyme comprises two identical 22-kDa subunits, each with one molecule of flavin mononucleotide. It is specific for NADH as the reductant and uses the quinones produced by G. trabeum (2,5-dimethoxy-1,4-benzoquinone and 4,5-dimethoxy-1,2-benzoquinone) as electron acceptors. The affinity of the reductase for these quinones is so high that precise kinetic parameters were not obtainable, but it is clear that k cat /K m for the quinones is greater than 10 8 M ؊1 s ؊1 . The reductase is encoded by a gene with substantial similarity to NAD(P)H:quinone reductase genes from other fungi. The G. trabeum quinone reductase may function in quinone detoxification, a role often proposed for these enzymes, but we hypothesize that the fungus has recruited it to drive extracellular oxyradical production.

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The Persistence of Decaying Wood in the Humus Layers of Northern Forests

Cited by 87 publications

References 0 publications

The seen and unseen world of the fallen tree.

The seen and unseen world of the fallen tree.

Differential Stress-Induced Regulation of Two Quinone Reductases in the Brown Rot BasidiomyceteGloeophyllum trabeum

An NADH:Quinone Oxidoreductase Active during Biodegradation by the Brown-Rot Basidiomycete Gloeophyllum trabeum

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