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Kingdom Fungi

It is a unique kingdom of heterotrophic organisms.

  • They show a great diversity in morphology and habitat.

  • Fungi are cosmopolitan and occur in air, water, soil, and on animals and plants.

    • They prefer to grow in warm and humid places.

    • Fungi are filamentous (Except Yeast).

      • Their bodies consist of long, slender thread-like structures called hyphae and their network is known as mycelium.

      • Some hyphae are continuous tubes filled with multinucleated cytoplasm known as coenocytic hyphae.

  • The cell walls of fungi are composed of chitin and polysaccharides.

Examples:

  • The common mushroom and toadstools.

  • White spots seen on mustard leaves are due to a parasitic fungus.

  • Yeast is used to make bread and beer. (unicellular fungi)

  • Puccinia causes rusting in wheat.

  • Penicillin is a source of antibiotics.

Saprophytes:

Most fungi are heterotrophic and absorb soluble organic matter from dead substrates.

Parasites:

  • The fungi are heterotrophic and depend on living plants and animals.

  • They can also live as symbionts – in association with algae as lichens and with roots of higher plants as mycorrhiza.

Reproduction:

  • Vegetative means – fragmentation, fission, and budding.

  • Asexual reproduction is by spores called conidia or sporangiospores or zoospores.

  • Sexual reproduction is by oospores, ascospores, and basidiospores****.

    • The various spores are produced in distinct structures called fruiting bodies.

    • The fusion of protoplasms between two motile or non-motile gametes is called plasmogamy.

      • Fusion of two nuclei called karyogamy.

      • Meiosis in zygotes results in haploid spores.

      • When a fungus reproduces sexually, two haploid hyphae of compatible mating types come together and fuse.

Exception: In Ascomycetes and Basidiomycetes, an intervening dikaryotic stage (two nuclei per cell) occurs which is called a dikaryon and the phase is called dikaryophase of fungus.

Phycomycetes:
Mucor; Credits - NCERT

  • Members of Phycomycetes are found in aquatic habitats and on decaying wood in moist and damp places or as obligate parasites on plants.

  • The mycelium is aseptate and coenocytic.

    • Asexual reproduction takes place by zoospores (motile) or by aplanospores (non-motile).

      • These spores are endogenously produced in sporangium.

    • A zygospore is formed by the fusion of two gametes.

      • These gametes are similar in morphology (isogamous) or dissimilar (anisogamous or oogamous).

Examples: Mucor, Rhizopus (the bread mold), and Albugo (the parasitic fungi on mustard).

Ascomycetes:

Aspergillus; Credits - NCERT

  • They are mostly multicellular. (Exception: yeast or Saccharomyces)

  • They are saprophytic, decomposers, parasitic or coprophilous.

  • Mycelium is branched and septate.

    • The asexual spores are conidia produced exogenously on the special mycelium called conidiophores.

      • Conidia on germination produce mycelium.

    • Sexual spores are called ascospores which are produced endogenously in sac-like asci.

      • These asci are arranged in different types of fruiting bodies called ascocarps.

Examples: Aspergillus, Claviceps, and Neurospora.

Note: Many members like morels and truffles are edible and are considered delicacies.

Basidiomycetes:

Agaricus; Credits - NCERT.

  • They grow in soil, on logs and tree stumps, and in living plant bodies as parasites.

  • The mycelium is branched and septate.

    • The asexual spores are generally not found, but vegetative reproduction by fragmentation is common.

      • The sex organs are absent, but plasmogamy is brought about by the fusion of two vegetative or somatic cells of different strains or genotypes.

        • The resultant structure is dikaryotic which ultimately gives rise to basidium.

      • Karyogamy and meiosis take place in the basidium producing four basidiospores.

  • The basidiospores are exogenously produced on the basidium.

    • The basidia are arranged in fruiting bodies called basidiocarps.

Examples: Agaricus (mushroom), Ustilago (smut), and Puccinia (rust fungus).

Deuteromycetes:

Trichoderma; Credits - Wikipedia

  • They are commonly known as imperfect fungi because only the asexual or vegetative phases of these fungi are found.

  • Once perfect (sexual) stages of members of Deuteromycetes were discovered they were often moved to ascomycetes and basidiomycetes.

    • The Deuteromycetes reproduce only by asexual spores known as conidia.

      • The mycelium is septate and branched.

    • Some members are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling.

Examples: Alternaria, Colletotrichum, and Trichoderma.

Kingdom Fungi

It is a unique kingdom of heterotrophic organisms.

  • They show a great diversity in morphology and habitat.

  • Fungi are cosmopolitan and occur in air, water, soil, and on animals and plants.

    • They prefer to grow in warm and humid places.

    • Fungi are filamentous (Except Yeast).

      • Their bodies consist of long, slender thread-like structures called hyphae and their network is known as mycelium.

      • Some hyphae are continuous tubes filled with multinucleated cytoplasm known as coenocytic hyphae.

  • The cell walls of fungi are composed of chitin and polysaccharides.

Examples:

  • The common mushroom and toadstools.

  • White spots seen on mustard leaves are due to a parasitic fungus.

  • Yeast is used to make bread and beer. (unicellular fungi)

  • Puccinia causes rusting in wheat.

  • Penicillin is a source of antibiotics.

Saprophytes:

Most fungi are heterotrophic and absorb soluble organic matter from dead substrates.

Parasites:

  • The fungi are heterotrophic and depend on living plants and animals.

  • They can also live as symbionts – in association with algae as lichens and with roots of higher plants as mycorrhiza.

Reproduction:

  • Vegetative means – fragmentation, fission, and budding.

  • Asexual reproduction is by spores called conidia or sporangiospores or zoospores.

  • Sexual reproduction is by oospores, ascospores, and basidiospores****.

    • The various spores are produced in distinct structures called fruiting bodies.

    • The fusion of protoplasms between two motile or non-motile gametes is called plasmogamy.

      • Fusion of two nuclei called karyogamy.

      • Meiosis in zygotes results in haploid spores.

      • When a fungus reproduces sexually, two haploid hyphae of compatible mating types come together and fuse.

Exception: In Ascomycetes and Basidiomycetes, an intervening dikaryotic stage (two nuclei per cell) occurs which is called a dikaryon and the phase is called dikaryophase of fungus.

Phycomycetes:
Mucor; Credits - NCERT

  • Members of Phycomycetes are found in aquatic habitats and on decaying wood in moist and damp places or as obligate parasites on plants.

  • The mycelium is aseptate and coenocytic.

    • Asexual reproduction takes place by zoospores (motile) or by aplanospores (non-motile).

      • These spores are endogenously produced in sporangium.

    • A zygospore is formed by the fusion of two gametes.

      • These gametes are similar in morphology (isogamous) or dissimilar (anisogamous or oogamous).

Examples: Mucor, Rhizopus (the bread mold), and Albugo (the parasitic fungi on mustard).

Ascomycetes:

Aspergillus; Credits - NCERT

  • They are mostly multicellular. (Exception: yeast or Saccharomyces)

  • They are saprophytic, decomposers, parasitic or coprophilous.

  • Mycelium is branched and septate.

    • The asexual spores are conidia produced exogenously on the special mycelium called conidiophores.

      • Conidia on germination produce mycelium.

    • Sexual spores are called ascospores which are produced endogenously in sac-like asci.

      • These asci are arranged in different types of fruiting bodies called ascocarps.

Examples: Aspergillus, Claviceps, and Neurospora.

Note: Many members like morels and truffles are edible and are considered delicacies.

Basidiomycetes:

Agaricus; Credits - NCERT.

  • They grow in soil, on logs and tree stumps, and in living plant bodies as parasites.

  • The mycelium is branched and septate.

    • The asexual spores are generally not found, but vegetative reproduction by fragmentation is common.

      • The sex organs are absent, but plasmogamy is brought about by the fusion of two vegetative or somatic cells of different strains or genotypes.

        • The resultant structure is dikaryotic which ultimately gives rise to basidium.

      • Karyogamy and meiosis take place in the basidium producing four basidiospores.

  • The basidiospores are exogenously produced on the basidium.

    • The basidia are arranged in fruiting bodies called basidiocarps.

Examples: Agaricus (mushroom), Ustilago (smut), and Puccinia (rust fungus).

Deuteromycetes:

Trichoderma; Credits - Wikipedia

  • They are commonly known as imperfect fungi because only the asexual or vegetative phases of these fungi are found.

  • Once perfect (sexual) stages of members of Deuteromycetes were discovered they were often moved to ascomycetes and basidiomycetes.

    • The Deuteromycetes reproduce only by asexual spores known as conidia.

      • The mycelium is septate and branched.

    • Some members are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling.

Examples: Alternaria, Colletotrichum, and Trichoderma.