The Biological Significance of Conjugate Nuclei in Coprinus lagopus and other Hymenomycetes*

Buller, A. H. Reginald

doi:10.1038/126686a0

Cited by 45 publications

(36 citation statements)

References 2 publications

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“…However, they are capable of contributing fertilizing nuclei to a haploid monokaryon, resulting in a new dikaryon (57,58,69); this reaction has been termed the Buller phenomenon (400). "Legitimate di-mon matings" (for "dikaryon-monokaryon matings") are those where both kinds of nuclei in the dikaryon are of compatible mating type to the nuclei of the monokaryon.…”

Section: Monokaryons and Dikaryonsmentioning

confidence: 99%

Life History and Developmental Processes in the BasidiomyceteCoprinus cinereus

Kües

2000

Microbiol Mol Biol Rev

433

336

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SUMMARY Coprinus cinereus has two main types of mycelia, the asexual monokaryon and the sexual dikaryon, formed by fusion of compatible monokaryons. Syngamy (plasmogamy) and karyogamy are spatially and temporally separated, which is typical for basidiomycetous fungi. This property of the dikaryon enables an easy exchange of nuclear partners in further dikaryotic-monokaryotic and dikaryotic-dikaryotic mycelial fusions. Fruiting bodies normally develop on the dikaryon, and the cytological process of fruiting-body development has been described in its principles. Within the specialized basidia, present within the gills of the fruiting bodies, karyogamy occurs in a synchronized manner. It is directly followed by meiosis and by the production of the meiotic basidiospores. The synchrony of karyogamy and meiosis has made the fungus a classical object to study meiotic cytology and recombination. Several genes involved in these processes have been identified. Both monokaryons and dikaryons can form multicellular resting bodies (sclerotia) and different types of mitotic spores, the small uninucleate aerial oidia, and, within submerged mycelium, the large thick-walled chlamydospores. The decision about whether a structure will be formed is made on the basis of environmental signals (light, temperature, humidity, and nutrients). Of the intrinsic factors that control development, the products of the two mating type loci are most important. Mutant complementation and PCR approaches identified further genes which possibly link the two mating-type pathways with each other and with nutritional regulation, for example with the cAMP signaling pathway. Among genes specifically expressed within the fruiting body are those for two galectins, β-galactoside binding lectins that probably act in hyphal aggregation. These genes serve as molecular markers to study development in wild-type and mutant strains. The isolation of genes for potential non-DNA methyltransferases, needed for tissue formation within the fruiting body, promises the discovery of new signaling pathways, possibly involving secondary fungal metabolites.

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Section: Monokaryons and Dikaryonsmentioning

confidence: 99%

Life History and Developmental Processes in the BasidiomyceteCoprinus cinereus

Kües

2000

Microbiol Mol Biol Rev

433

336

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“…This leads to dikaryotization of the haploid homokaryon resulting in formation of a new dikaryon (the Buller phenomenon; Buller, 1930;Quintanilha, 1937). Sometimes both nuclei of the dikaryon are transferred to the haploid homokaryon and displace the resident nucleus.…”

Section: Mating Interactions Between Dikaryons/heterokaryons/diploidsmentioning

confidence: 98%

“…Mating reactions with four different haploid testers can be used as a criterion to differentiate between the hemicompatible diploids. As Bs diploids cause the fluffy testers to become crustose, indicating that the diploids dikaryotize the haploid homokaryons (similar to the Buller phenomenon; Buller, 1930; see section 2). The A¼ Bs strain mates with testers having a different A allele (dual mater), whereas the As B¼ strain mates with testers carrying a different B allele (dual mater).…”

mentioning

confidence: 94%

From dikaryon to diploid

Banuett¹

2015

Fungal Biology Reviews

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Dikaryon Diploid Haploidization Heterokaryon a b s t r a c t The dikaryon is the persistent vegetative phase of most basidiomycetes and arises by cell fusion of two haploids carrying different mating type alleles. The diplophase is restricted to a single cell (the basidium) where meiosis takes place. Cell fusion and karyogamy are thus temporally and spatially separated. The dikaryon is characterized by the presence in each cell of two genetically distinct nuclei in a 1:1 ratio and by clamp connections, structures involved in partitioning of the nuclei during their synchronous division. In Coprinopsis cinerea and Schizophyllum commune, with two mating type loci (A and B), heterokaryons with identical A alleles exhibit nuclear migration but no clamps, and those with identical B alleles have unfused clamps (pseudoclamps) and no nuclear migration. Armillaria species are exceptional among basidiomycetes because of their persistent vegetative diploid phase with no clamp connections. Cell fusion is followed immediately by karyogamy. Haploidization of the diploid nucleus may occur in the fruiting body, resulting in a new dikaryophaseediplophase. Diploids in Ustilago maydis were the first to be synthesized in any basidiomycete. They played a critical role in pioneering studies on DNA recombinationand repair. Subsequently diploids were generated in C. cinerea, S. commune, Microbotryum violaceum, and Cryptococcus neoformans. Dikaryons (or heterokaryons) and diploids of the same genotype exhibit phenotypic differences. The reason is not known but evidence indicates that gene expression differs when the same genetic information resides in two nuclei versus one nucleus in the same cell. Diploids in basidiomycete fungi are very stable by themselves but become unstable in 2N þ N or 2N þ 2N dikaryons. Instability results in haploidization (gradual loss of chromosomes) of the diploid nucleus. The mechanism that triggers this instability is not known.

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“…Thus, recessive mutations induced in the haploid oidia will be expressed. These can be recovered and analyzed even in the complete absence of viable spore formation because AmutBmut colonies will donate nuclei to monokaryotic strains of conventional mating type, just as in a conventional di-mon mating (Buller 1930). Such AmutBmut strains have been used to obtain many developmental mutants in this organism (Kanda and Ishikawa 1986;Kanda et al 1989a,b; A.B.…”

Section: Constitutive Mating-type Mutantsmentioning

confidence: 97%

Meiosis in Mycelial Fungi

Pukkila

1994

Growth, Differentiation and Sexuality

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The Biological Significance of Conjugate Nuclei in Coprinus lagopus and other Hymenomycetes*

Cited by 45 publications

References 2 publications

Life History and Developmental Processes in the BasidiomyceteCoprinus cinereus

Life History and Developmental Processes in the BasidiomyceteCoprinus cinereus

From dikaryon to diploid

Meiosis in Mycelial Fungi

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