Phycomyces sp.
Phycomyces sp.: https://marylandbiodiversity.com/species/22005
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2 Records

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Phycomyces is an important model organism for the study of mating types as well as tropism in fungi, particularly phototropism.

Description

The genus Phycomyces is most conspicuous when it forms sporangia at the tips of long, thread-like 'stems' called sporangiophores. These often form dense clusters having the appearance of hair. Identification of species requires microscopic analysis of the spores.

Where To Find

Phycomyces may be found in almost any damp habitat. Look for white or black threads growing on dung, dead insects or plant material.

Note that Phycomyces is not the only species of fungus that grows on dung and other species, including other Zygomycota, should be considered.

Eating mushrooms can be dangerous. One should do so only with expert advice and great care. MBP accepts no liability for injury sustained in consuming fungi or other biodiversity. Use of media featured on Maryland Biodiversity Project is only permitted with express permission of the photographer.

Source: Wikipedia

Phycomyces
Closeup of the Phycomyces sporangium
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Mucoromycota
Class: Mucoromycetes
Order: Mucorales
Family: Phycomycetaceae
Genus: Phycomyces
Kunze
Species

Phycomyces is a genus of fungus in the Zygomycota phylum. They are known for their strong phototropism response and helical growth of the sporangium. The best studied species is Phycomyces blakesleeanus.

Asexual reproduction

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Phycomyces can reproduce via extension of mycelia, or by production of spores either asexually or sexually. The asexual cycle includes the formation of spore containing sporangia borne on the top of sporangiophores that may extend 10 to 15 cm above the surface of the fungal colony from which they emerged. The long filamentous sporangiophores respond to divergent environmental signals including light, gravity, wind, chemicals, and adjacent objects. The sporangia contain vegetative spores with one to six haploid nuclei. When these spores are dispersed, they can establish new colonies.

Sexual reproduction

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Phycomyces have two mating types that are indistinguishable morphologically. The sexual cycle is thought to occur by the following steps. Two hyphae of different mating type encounter each other, and their tips undergo a septation event to produce gametangia. Gametangia are haploid multinuclear cells equivalent to gametes. The two gametangia fuse to form an immature zygospore. Initially the developing zygospore contains thousands of nuclei contributed by the gametangia. During the course of zygospore maturation and dormancy, lasting several months, most nuclei are degraded. It is thought that ordinarily two surviving nuclei, one from each parent, fuse to form a diploid cell that then undergoes meiosis to form haploid meiotic products.[1][2] These products then reproduce by mitotic divisions leading to the formation of a sporangium structure (germosporangium) that develops out from the zygospore. The germosporangium contains spores (germspores) that have one to six haploid nuclei like those in the vegetative sporangium.

References

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  1. ^ Eslava AP, Alvarez MI, Delbrück M (October 1975). "Meiosis in Phycomyces". Proc. Natl. Acad. Sci. U.S.A. 72 (10): 4076–80. Bibcode:1975PNAS...72.4076E. doi:10.1073/pnas.72.10.4076. PMC 433141. PMID 1060090.
  2. ^ Eslava AP, Alvarez MI, Burke PV, Delbrück M (July 1975). "Genetic recombination in sexual crosses of phycomyces". Genetics. 80 (3): 445–62. doi:10.1093/genetics/80.3.445. PMC 1213351. PMID 17248685.
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