Narinder Singh, Academic Content Writer at Edumarz
- The Fungi makes up a special kingdom of heterotrophic organisms. Besides showing an excellent variation in morphology and habitat, they’re cosmopolitan and occur in air, water, soil, and on animals and plants.They also wish to grow in warm and humid places.
Except Yeasts, that are unicellular, Fungi are filamentous. Long, slender thread like structures called hyphae are present in their bodies. The network of hyphae is understood as mycelium. Some hyphae, called coenocytic hyphae, are continuous tubes stuffed containing multi-nucleated cytoplasm, though others have septae or cross walls. Furthermore the cell walls of fungi are formed from Chitin and Polysaccharides.
Additionally, they also live as symbionts-alongside algae as Lichens and with roots of upper plants as Mycorrhiza.
- Fragmentation, fission and budding are the foremost modes for copying in Fungi. The reproduction amongst them occurs through spores Called Conidia or Zoospores, whereas the sexual reproduction occurs through Oospores, ascospores and basidiospores. The assembly of varied spores Occur in distinct structures called fruiting bodies. The sexual cycle comprises the Following steps:
- Plasmogamy involving the fusion of protoplasms between two motile or Non-motile gametes.
- Karyogamy involving the fusion of two nuclei.
- Formation of haploid spores as on account of Meiosis in Zygote.
During the sexual reporduction of a fungus, two haploid hyphae of compatible Mating types move and fuse. In some fungi, diploid cells (2n) are immediately produced through fusion of two haploid cells, whereas in other Fungi (ascomycetes and basidiomycetes), a phase called dikaryophase is achieved , which is an intervening dikaryotic stage. Afterwards, fusion of the Parental nuclei occur and also the cells become diploid. Also, the fungi forms Fruiting bodies within which the meiosis occurs, and it finishes up with the Formation of haploid spores.
- Phycomycetes: In these types of Fungi, Agametogenesis occurs by zoospores(motile) or by aplanospores (non-motile), with these spores produced endogenously in Sporangium. Formation of zygospore occurs through the fusion of two gametes.These gametes are additionally morphologically similar or dissimilar. The examples include: Rhizopus (bread mould), Mucor and Albugo (Parasitic Fungi on Mustard).
- Ascomycetes: The’re mostly multi-cellular, saprophytic, decomposers, parasitic or coprophilous (growing on dung) with branched and Septate Mycelium.- Ascospores are produced endogenously in sac like asci, with the arrangement of those asci in several fruiting bodies called ascocarps.As an example, Neurospora, Claviceps and Aspergillus, with Neurospora getting utilised in biochemical and genetic work.
- Basidiomycetes: They include mushrooms, bracket fungi or puffballs. Vegetative reproduction by Fragmentation is common. Though they donot contain sex organs, “Plasmogamy occurs by fusion of two vegetative or somatic cells of diverse strains or genotypes”. The resultant Dikaryotic structure gives rise to Basidium. Karyogamy and Meiosis occurring within the Basidium produces four Basidiospores. Here basidiospores are exogenously produced on the Basidium, with Basidia arranged in fruiting bodies called Basidiocarps. Examples include: Puccinia (rust fungus), Agaricus (Mushroom) and Ustilago(Smut).
- Deuteromycetes: As only the vegetative or asexual phases of them is Known, the’re noted as imperfect fungi. They reproduce only by asexual spores called Conidia, with separate and branched Mycelium.Examples include: Colletotrichum, Trichoderma and Alternaria.