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: \n

• 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:

• 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:

• 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:

• 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%%.

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