What type of hyphae do chytridiomycota have

Zygomycetes play a considerable commercial role. The metabolic products of other species of Rhizopus are intermediates in the synthesis of semi-synthetic steroid hormones. Zygomycetes have a thallus of coenocytic hyphae in which the nuclei are haploid when the organism is in the vegetative stage. When spores land on a suitable substrate, they germinate and produce a new mycelium. Sexual reproduction starts when conditions become unfavorable.

The developing diploid zygospores have thick coats that protect them from desiccation and other hazards. They may remain dormant until environmental conditions are favorable. When the zygospore germinates, it undergoes meiosis and produces haploid spores, which will, in turn, grow into a new organism. The majority of known fungi belong to the Phylum Ascomycota , which is characterized by the formation of an ascus plural, asci , a sac-like structure that contains haploid ascospores. Many ascomycetes are of commercial importance.

Some play a beneficial role, such as the yeasts used in baking, brewing, and wine fermentation, plus truffles and morels, which are held as gourmet delicacies. Aspergillus oryzae is used in the fermentation of rice to produce sake. Other ascomycetes parasitize plants and animals, including humans. For example, fungal pneumonia poses a significant threat to AIDS patients who have a compromised immune system.

Ascomycetes not only infest and destroy crops directly; they also produce poisonous secondary metabolites that make crops unfit for consumption. Filamentous ascomycetes produce hyphae divided by perforated septa, allowing streaming of cytoplasm from one cell to the other. Conidia and asci, which are used respectively for asexual and sexual reproductions, are usually separated from the vegetative hyphae by blocked non-perforated septa.

At fertilization, the antheridium and the ascogonium combine in plasmogamy without nuclear fusion. In each ascus, two or more haploid ascospores fuse their nuclei in karyogamy. During sexual reproduction, thousands of asci fill a fruiting body called the ascocarp.

The diploid nucleus gives rise to haploid nuclei by meiosis. The fungi in the Phylum Basidiomycota are easily recognizable under a light microscope by their club-shaped fruiting bodies called basidia singular, basidium , which are the swollen terminal cell of a hypha. This group also includes shelf fungus, which cling to the bark of trees like small shelves. In addition, the basidiomycota includes smuts and rusts, which are important plant pathogens; toadstools, and shelf fungi stacked on tree trunks.

Most edible fungi belong to the Phylum Basidiomycota; however, some basidiomycetes produce deadly toxins. For example, Cryptococcus neoformans causes severe respiratory illness. Spores are generally produced through sexual reproduction, rather than asexual reproduction. Kingdom Fungi. Phylum Chytridiomycota — chytrids. Phylum Zygomycota — zygomycetes. Phylum Glomeromycota — glomeromycetes.

Phylum Ascomycota — ascomycetes; sac fungi. Phylum Basidiomycota — basidiomycetes; club fungi. Glyomeromycetes and tree roots : This image illustrates the bitrophic relationship between a glomeromycota Gigaspora margarita and the roots of a plant Lotus corniculatus. The glomeromycetes do not reproduce sexually and cannot survive without the presence of plant roots. They have coenocytic hyphae and reproduce asexually, producing glomerospores. The biochemical and genetic characterization of the Glomeromycota has been hindered by their biotrophic nature, which impedes laboratory culturing.

This obstacle was eventually surpassed with the use of root cultures. With the advent of molecular techniques, such as gene sequencing, the phylogenetic classification of Glomeromycota has become clearer. This gene is highly conserved and commonly used in phylogenetic studies so it was isolated from spores of each taxonomic group.

Using a molecular clock approach based on the substitution rates of SSU sequences, scientists were able to estimate the time of divergence of the fungi. This analysis shows that all glomeromycetes probably descended from a common ancestor and million years ago, making them a monophyletic lineage. A long-held theory is that Glomeromycota were instrumental in the colonization of land by plants. Privacy Policy. Skip to main content.

Search for:. Classifications of Fungi. Chytridiomycota: The Chytrids Chytrids are the most primitive group of fungi and the only group that possess gametes with flagella. Learning Objectives Describe the ecology and reproduction of chytrids.

Key Takeaways Key Points The first recognizable chytrids appeared more than million years ago during the late pre-Cambrian period. Like protists, chytrids usually live in aquatic environments, but some species live on land. Some chytrids are saprobes while others are parasites that may be harmful to amphibians and other animals. Chytrids reproduce both sexually and asexually, which leads to the production of zoospores.

Chytrids have chitin in their cell walls; one unique group also has cellulose along with chitin. Chytrids are mostly unicellular, but multicellular organisms do exist. Key Terms chytridiomycete : an organism of the phylum Chytridiomycota zoospore : an asexual spore of some algae and fungi flagellum : a flagellum is a lash-like appendage that protrudes from the cell body of certain prokaryotic and eukaryotic cells coenocytic : a multinucleate cell that can result from multiple nuclear divisions without their accompanying cytokinesis.

Zygomycota: The Conjugated Fungi Zygomycota, a small group in the fungi kingdom, can reproduce asexually or sexually, in a process called conjugation. Learning Objectives Describe the ecology and reproduction of Zygomycetes. Key Takeaways Key Points Most zygomycota are saprobes, while a few species are parasites. Zygomycota usually reproduce asexually by producing sporangiospores. Zygomycota reproduce sexually when environmental conditions become unfavorable. To reproduce sexually, two opposing mating strains must fuse or conjugate, thereby, sharing genetic content and creating zygospores.

The resulting diploid zygospores remain dormant and protected by thick coats until environmental conditions have improved. When conditions become favorable, zygospores undergo meiosis to produce haploid spores, which will eventually grow into a new organism.

Key Terms zygomycete : an organism of the phylum Zygomycota karyogamy : the fusion of two nuclei within a cell zygospore : a spore formed by the union of several zoospores conjugation : the temporary fusion of organisms, especially as part of sexual reproduction.

Ascomycota: The Sac Fungi Most fungi belong to the Phylum Ascomycota, which uniquely forms of an ascus, a sac-like structure that contains haploid ascospores. Learning Objectives Describe the ecology and the reproduction of Ascomycetes. Key Takeaways Key Points Ascomycota fungi are the yeasts used in baking, brewing, and wine fermentation, plus delicacies such as truffles and morels.

Ascomycetes are filamentous and produce hyphae divided by perforated septa. Ascomycetes frequently reproduce asexually which leads to the production of conidiophores that release haploid conidiospores. The antheridium and the ascogonium combine in plasmogamy at the time of fertilization, followed by nuclei fusion in the asci. In the ascocarp, a fruiting body, thousands of asci undergo meiosis to generate haploid ascospores ready to be released to the world.

Basidiomycota: The Club Fungi The basidiomycota are mushroom-producing fungi with developing, club-shaped fruiting bodies called basidia on the gills under its cap.

Learning Objectives Describe the ecology and reproduction of the Basidiomycota. Asexual reproduction is via conidiospores. The Ascomycetes include fungi that cause chestnut blight and Dutch elm disease.

Claviceps purpurea is a parasite on rye grass that causes ergot. Basidiomycota club fungi : Basidiomycetes also possess septate hyphae. The sexual spores, called basidiospores, are produced by a club-shaped structure called a basidium. In mushrooms the basidia are found along the gills or pores on the underside of the cap.

Some mushrooms produce toxins that are lethal to humans.