what is ascomycetes?? Dont spam
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Answer:
embers of the phylum Ascomycota are known as ascomycetes. Ascomycota is the largest phylum of the kingdom fungi and has around 64000 species.
They come under the sub-kingdom Dikarya (presence of dikaryon).
They produce sexual non-motile spores known as ascospores. They are produced in a sac-like structure known as an ascus. Each ascus contains 4-8 ascospores. They are commonly known as sac-fungi.
Ascomycetes have a diverse habitat and feeding habit, some are saprophytes whereas others are pathogen causing various diseases in animals and plants. Some of the ascomycetes are edible as mushrooms. Some of them live in a symbiotic association as lichens and mycorrhiza.
Common examples of ascomycetes include yeast, powdery mildews, cup fungi, morels, truffles, Neurospora, Aspergillus, Cladonia, Penicillium, Candida, Claviceps, etc.
Ascomycetes are economically very important. We get fermented food (bread, cheese, alcoholic beverages), antibiotics (Penicillin) and various chemicals. Many species are used in biological studies and research (yeast, Neurospora). Morels and truffles are used as delicacies.
Ascomycetes are further classified based on the different structures of asci bearing structures and methods of the release of ascospores.
General Characteristics of Ascomycetes
One character that is present is most of the ascomycetes is a reproductive structure known as ascus or asci
Mostly they are terrestrial, parasitic or coprophilous
They are unicellular or multicellular fungi
The mycelium is made up of septate and branched hyphae
The cell wall is made up of chitin or ꞵ-glucans
There is cytoplasmic continuity due to septal pores
Asexual reproduction is by the formation of conidia exogenously on conidiophores
Yeast reproduces asexually by budding
Sexual reproduction is by conjugation between two gametangia. They are either homothallic or heterothallic
The fruiting body is known as ascocarp. There are four types of ascocarps:
Cleistothecium- The fruiting body is spherical and remains tightly closed, e.g. Aspergillus
Perithecium- The fruiting body is flask-shaped with one external opening, e.g. Neurospora
Apothecium- The fruiting body is cup-shaped and asci are present in hymenium, e.g. Peziza
Ascostroma- There is no differentiated fruiting body. Asci are present in the stroma, e.g. Mycosphaerella
Ascospores are produced endogenously in asci
Sexual Reproduction in Ascomycetes
Two different mating types hyphae come together and fuse
Plasmogamy takes place, but it does not follow karyogamy immediately
The fused structure contains two haploid nuclei from each parent, i.e. dikaryon
New hyphae are produced with dikaryotic cells
At the tip of the hyphae, asci develop in the ascocarp
In each ascus, two nuclei fuse together (karyogamy) to form a diploid zygote
Formation of Ascospores: The diploid zygote undergoes meiosis to form 4 haploid nuclei, which undergo mitotic division to form 8 haploid nuclei. Each of the nuclei accumulates cytoplasm and a thick cell wall surrounds it. These are known as ascospores
Ascospores are released from asci through pore, slit or hinged lid and dispersed by air currents
Under favourable conditions, ascospores germinate to form new mycelia
Economic Importance of Ascomycetes
Ascomycota is the biggest group of fungi having diverse habitat. They are cosmopolitan and we derive many useful products from them. We get many foods, medicines and chemical products from them.
Entire brewing, bread and cheese making industry depends on yeast for fermented products
Who doesn’t know about antibiotic, Penicillin, which we get from Penicillium chrysogenum
Ciclosporin, an immunosuppressor is derived from the fungus Tolypocladium niveum. It is used in organ transplants and autoimmune diseases
Many organic acids and enzymes are produced by ascomycetes, e.g. citric acid, gluconic acid, amylases, proteases, etc.
Claviceps purpurea (Ergot) is used as medicine to stop excessive bleeding during menstrual periods and to speed up labour
Different kinds of cheese are prepared from different Penicillium species, e.g. Camembert, Brie, Roquefort, etc.
Aspergillus is used to prepare soy sauce and to prepare other Asian alcoholic beverages
Morels, Truffles and lobster mushroom are used as fungal delicacies
Neurospora, Saccharomyces, etc. are widely used to study genetics
Answer:
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species.Many ascomycetes are pathogens, both of animals, including humans, and of plants.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. Filamentous ascomycetes produce hyphae divided by perforated septa, allowing streaming of cytoplasm from one cell to another.Most Ascomycota can reproduce using either method or even using both. In asexual reproduction, the fungus undergoes budding or fission, where cells from the fungus divide and split, forming new, genetically identical fungi that can then break off and grow on their own.Ascomycota species can be found on dry land around the world, in habitats ranging from tropical and temperate forests to grasslands and beyond. There are even species of ascomycota that live in extreme environments. One example is Coccidioides immitis.Ecology. The Ascomycota fulfil a central role in most land-based ecosystems. They are important decomposers, breaking down organic materials, such as dead leaves and animals, and helping the detritivores (animals that feed on decomposing material) to obtain their nutrients.