Stipe Elongation in Fruit Bodies

Sexual development in the mushroom Coprinus cinereus is under the control of two mating type loci, A and B. When two haploid homokaryons with compatible alleles at both A and B loci are mated, the coordinated activities of A- and B-regulated pathways lead to formation of a mycelium termed the dikaryon, in which the two nuclei from the mating partners pair in each cell without fusing. The dikaryon is a prolonged mycelial stage that can be induced to develop a multicellular structure, the mushroom, under proper environmental conditions. The two nuclei fuse in specialized cells on the mushroom and immediately undergo meiosis to complete the sexual life cycle. It has been established recently that the A genes encode two classes of homeodomain proteins while the B genes encode pheromones and their receptors. More recently, molecular genetics has been used to reveal genes that work downstream of the mating type genes to regulate dikaryon formation, mushroom morphogenesis, and meiosis.

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“…51), and development-dependent karyogamy, meiosis and basidiospore formation. Therefore, many genes are predicted to be involved in fruiting.…”

Section: Mushroom Morphogenesismentioning

confidence: 99%

Molecular genetics of sexual development in the mushroom Coprinus cinereus

Kamada

2002

BioEssays

103

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“…6, this tissue is directly connected to the primary gills and thereby provides an anchor required during expansion of the cap mediated by tangential growth of the meristemoid tissue of the cap (Reijnders, 1979 ; for review see Moore, 1998). The same tissue of the stipe is also involved in the process of rapid stipe elongation (see review by Kamada, 1994) where a strong hyphal adherence is essential for stability of the stipe. It is tempting to speculate about the function of the two galectin proteins.…”

Section: Cellular and Subcellular Localization Of The Galectinsmentioning

confidence: 99%

“…Such a system would enable the fungus to modulate its entire hyphal surface at specific periods during development. If galectins play a role in hyphal-hyphal interactions in the fruiting body, this may be an important mechanism to consider, because fungal morphogenesis is often achieved by rapid growth of cells already present within the tissue and not by cellular division (see the reviews by Gooday, 1975 ;Kamada, 1994 ;Moore, 1998). Thus, hyphal growth occurs along the lateral walls of the hyphae and not at the tip.…”

Section: Secretion Of the Galectinsmentioning

confidence: 99%

Fruiting body development in Coprinus cinereus: regulated expression of two galectins secreted by a non-classical pathway The GenBank accession number for the sequence reported in this paper is AF130360

et al. 2000

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Fruiting body formation in the basidiomycete Coprinus cinereus is a developmental process that occurs as a response of the mycelium to external stimuli. First, localized, highly branched hyphal structures (knots) are formed as a reaction to nutritional depletion. Hyphal-knot formation is repressed by light ; however, light signals are essential for the development of the hyphal knot into an embryonic fruiting body (primordium) as well as karyogamy, meiosis and fruiting body maturation. The role of the different environmental signals in the initial phases of fruiting body development was analysed. It was observed that two fungal galectins, Cgl1 and Cgl2, are differentially regulated during fruiting body formation. cgl2 expression initiated in early stages of fruiting body development (hyphal knot formation) and was maintained until maturation of the fruiting body, whereas cgl1 was specifically expressed in primordia and mature fruiting bodies. Immunofluorescence and immunoelectron microscopy studies detected galectins within specific fruiting body tissues. They localized in the extracellular matrix and the cell wall but also in membrane-bound bodies in the cytoplasm. Heterologous expression of Cgl2 in Saccharomyces cerevisiae indicated that secretion of this protein occurred independently of the classical secretory pathway.

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“…We have isolated and analyzed mutants defective in stipe elongation (Takemaru and Kamada, 1972;Kamada et al, 1984;Muraguchi et al, 1999). Biochemical and light-and electronmicroscopic studies on those mutants and the wild type have revealed fundamental aspects of stipe elongation, such as diffuse extension growth of cylindrical stipe cells causing stipe elongation, helical orientation of chitin microfibrils in the walls of stipe cells throughout development, and changes in mechanical properties of the stipe wall parallel with the elongation rate during development (Gooday, 1985;Kamada, 1994). However, molecular mechanisms underlying the regulation of stipe development remain poorly understood.…”

mentioning

confidence: 98%