Chromosomal Abnormalities Associated with Strain Degeneration in the Cultivated Mushroom,Agaricus bisporus

Horgen, Paul A.; Carvalho, Daisy; Sonnenberg, A.S.M.; Li, Aimin; Griensven, L. J. L. D. van

doi:10.1006/fgbi.1996.0038

Cited by 30 publications

(18 citation statements)

References 22 publications

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“…2A). Several TEs have been observed to be actively moving from site to site within the genome (16), and this provides one possible explanation for the development of anomalies, such as sectors or stroma from within otherwise healthy, stable cultures (17).…”

Section: Resultsmentioning

confidence: 99%

Genome sequence of the button mushroomAgaricus bisporusreveals mechanisms governing adaptation to a humic-rich ecological niche

Morin

Kohler

Baker

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

350

307

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Agaricus bisporus is the model fungus for the adaptation, persistence, and growth in the humic-rich leaf-litter environment. Aside from its ecological role, A. bisporus has been an important component of the human diet for over 200 y and worldwide cultivation of the “button mushroom” forms a multibillion dollar industry. We present two A. bisporus genomes, their gene repertoires and transcript profiles on compost and during mushroom formation. The genomes encode a full repertoire of polysaccharide-degrading enzymes similar to that of wood-decayers. Comparative transcriptomics of mycelium grown on defined medium, casing-soil, and compost revealed genes encoding enzymes involved in xylan, cellulose, pectin, and protein degradation are more highly expressed in compost. The striking expansion of heme-thiolate peroxidases and β-etherases is distinctive from Agaricomycotina wood-decayers and suggests a broad attack on decaying lignin and related metabolites found in humic acid-rich environment. Similarly, up-regulation of these genes together with a lignolytic manganese peroxidase, multiple copper radical oxidases, and cytochrome P450s is consistent with challenges posed by complex humic-rich substrates. The gene repertoire and expression of hydrolytic enzymes in A. bisporus is substantially different from the taxonomically related ectomycorrhizal symbiont Laccaria bicolor . A common promoter motif was also identified in genes very highly expressed in humic-rich substrates. These observations reveal genetic and enzymatic mechanisms governing adaptation to the humic-rich ecological niche formed during plant degradation, further defining the critical role such fungi contribute to soil structure and carbon sequestration in terrestrial ecosystems. Genome sequence will expedite mushroom breeding for improved agronomic characteristics.

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Section: Resultsmentioning

confidence: 99%

Genome sequence of the button mushroomAgaricus bisporusreveals mechanisms governing adaptation to a humic-rich ecological niche

Morin

Kohler

Baker

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

350

307

View full text Add to dashboard Cite

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“…Fungal culture degeneration is usually irreversible and inheritable (Li et al 1994;Horgen et al 1996;Ryan et al 2002). Apart from the reports of phenotypic variation in the degenerative fungal cultures with Metarhizium anisopliae (Wang et al 2005a, b), little information is available to explain the culture instability of C. militaris at the molecular level.…”

Section: Introductionmentioning

confidence: 96%

Agrobacterium tumefaciens-mediated transformation as a tool for insertional mutagenesis in medicinal fungus Cordyceps militaris

Zheng

Huang

Cao³

et al. 2011

Fungal Biology

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Section: Introductionmentioning

confidence: 99%

“…Like many other fungi (Morrow et al, 1989;Kale & Bennett, 1992;Li et al, 1994), it frequently shows culture degeneration (sterile sectorization): a loss or reduction in sporulation and virulence with a fluffy-mycelium type growth. Fungal culture degeneration is usually irreversible and inheritable, and can result in great commercial losses (Li et al, 1994;Horgen et al, 1996;Ryan et al, 2003).Apart from the reports of secondary metabolite decline in degenerative fungal cultures (Wing et al, 1995; Guzman-dePena & Ruiz-Herrera, 1997;Ryan et al, 2002; Kale et al, 2003), little information is available to explain fungal culture instability at the molecular level. However, genomic DNA methylation was reported in a sector of Fusarium oxysporum after successive subculturing (Kim, 1997).…”

mentioning

confidence: 99%

Colony sectorization of Metarhizium anisopliae is a sign of ageing

2005

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Spontaneous phenotypic degeneration resulting in sterile sectors is frequently observed when culturing filamentous fungi on artificial medium. Sterile sectors from two different strains of the insect pathogenic fungus Metarhizium anisopliae were investigated and found to contain reduced levels of cAMP and destruxins (insecticidal peptides). Microarray analysis using slides printed with 1730 clones showed that compared to wild-type, sterile sectors down-regulated 759 genes and upregulated 27 genes during growth in Sabouraud glucose broth or on insect cuticle. The differentially expressed genes are largely involved in cell metabolism (18?8 %), cell structure and function (13?6 %) and protein metabolism (8?8 %). Strong oxidative stress was demonstrated in sectorial cultures using the nitro blue tetrazolium assay and these cultures show other syndromes associated with ageing, including mitochondrial DNA alterations. However, genes involved in deoxidation and self-protection (e.g. heat-shock proteins, HSPs) were also upregulated. Further evidence of physiological adaptation by the degenerative sectorial cultures included cell-structure reorganization and the employment of additional signalling pathways. In spite of their very similar appearance, microarray analysis identified 181 genes differentially expressed between the two sectors, and the addition of exogenous cAMP only restored conidiation in one of them. Most of the differentially expressed genes were involved in catabolic or anabolic pathways, but the latter included genes for sporulation. Compared to the mammalian ageing process, sectorization in M. anisopliae showed many similarities, including similar patterns of cAMP production, oxidative stress responses and the involvement of HSPs. Thus, a common molecular machinery for ageing may exist throughout the eukaryotes. INTRODUCTIONThe ascomycete Metarhizium anisopliae is a widespread, soil-borne pathogen of insects, ticks and mites (Roberts & St Leger, 2004). Strains of this fungus are being developed for the control of pest species (Butt et al., 2001). Like many other fungi (Morrow et al., 1989;Kale & Bennett, 1992;Li et al., 1994), it frequently shows culture degeneration (sterile sectorization): a loss or reduction in sporulation and virulence with a fluffy-mycelium type growth. Fungal culture degeneration is usually irreversible and inheritable, and can result in great commercial losses (Li et al., 1994;Horgen et al., 1996;Ryan et al., 2003).Apart from the reports of secondary metabolite decline in degenerative fungal cultures (Wing et al., 1995; Guzman-dePena & Ruiz-Herrera, 1997;Ryan et al., 2002; Kale et al., 2003), little information is available to explain fungal culture instability at the molecular level. However, genomic DNA methylation was reported in a sector of Fusarium oxysporum after successive subculturing (Kim, 1997). In another case, fungal morphological instability was linked to dsRNA virus infection (Dawe & Nuss, 2001).In this study, the spontaneous sterile sectors from two genetically di...

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Chromosomal Abnormalities Associated with Strain Degeneration in the Cultivated Mushroom,Agaricus bisporus

Cited by 30 publications

References 22 publications

Genome sequence of the button mushroomAgaricus bisporusreveals mechanisms governing adaptation to a humic-rich ecological niche

Genome sequence of the button mushroomAgaricus bisporusreveals mechanisms governing adaptation to a humic-rich ecological niche

Agrobacterium tumefaciens-mediated transformation as a tool for insertional mutagenesis in medicinal fungus Cordyceps militaris

Colony sectorization of Metarhizium anisopliae is a sign of ageing

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