Phylum Chytridiomycota

• Kingdom Fungi: General Characteristics

  • Eukaryotic
  • They have cell walls
  • Reproduce Sexually and Asexually
  • Heterotrophs
  • "external digestion" – secretes enzymes to decompose complex molecules into simple compounds. e.g. B – glucosidases, a – amylases, and glucoamylases
  • Have major role in ecosystems
• Phylum Chytridiomycota


  • Distinguish by having zoospores
  • Chytridion which means little pot
  • Microscopic in size
  • Few species in the Order Chytridiales causes plant disease, and one species has been known (Batrachochytrium dendrobatidis) to cause disease in frogs and amphibians
  • There are 3 Orders mainly: Chytridiales, Blastocadiales, and Monoblepharidales
  • Only 1 class: Chytridiomycetes
• Potato Wart caused by Synchytrium endobioticum
• Phylum Chytridiomycota


  • The first fungus to appear
  • Individuals of this kingdom is also called lower fungi or algal fungi that is forming aseptated hyphae
  • Often called as Chytrids
  • Unique among all fungi due to having the motile spore
• Characteristics of Chytridiomycota


  • Cell walls are made up of Chitin and Glucan
  • Feed on both living and decaying organisms
  • Are mostly aquatic; not terrestrial
  • Sexual reproduction is variable; may be isogamous, anisogamous and oogamous
• Characteristics of Chytridiomycota


  • Asexual reproduction by zoospores have a single posterior whiplash flagellum
  • Some individuals have alternation of generations in their life cycle
  • Somatic phase consists from unicellular with rhizoids or multicellular (mycelium with aseptated hyphae)
• Rhizoid


  • Root like structure having protoplasm without nuclei bearing vegetative structures (zoosporangia)
  • Some rhizoids bears one zoosporangium per thallus – monocentric; others produce multiple zoosporangia – polycentric
  • The function of rhizoid is to anchor the Thallus on the surface of feed and increase surface area for absorption
• Thallus


  • Refers to the body or vegetative structure of the fungus
  • Unlike higher fungi like mushrooms or molds, which often have complex multicellular structures, the thallus of chytrids is typically simpler and can range from unicellular to multicellular forms
  • The thallus of chytrids is usually composed of a single cell or a mass of cells, and it lacks the organized tissues found in more advanced fungi
  • Irregularly shaped
• Sporangium


  • Specialized reproductive structure where spores are produced
  • Sporangia can be formed directly on the thallus or on specialized reproductive structures called sporangiophores
• Cysts


  • A protective structure formed by some chytrids during unfavorable conditions
  • Cysts enable the chytrid to survive adverse environmental conditions until conditions become favorable for growth and reproduction again
• Zoospores


  • Flagellated spores produced within sporangia
  • are unique to chytrids and possess one or more flagella, allowing them to move actively through aquatic environments
• Asexual Reproduction


  1. Asexually uses zoospores

  2. In asexual reproduction, zoospores release from zoosporangium within a pore at the top of zoosporangium called Operculum then will swim until it locates a fresh substrate, each will eventually lose its flagellum , The nucleus undergoes several Mitotic Divisions - resulting in a Multinucleate. Finally, cleavage of the protoplasm occurs, which produces individual zoospores that are released through a pore
• Sexual Reproduction


  1. Haploid is dominant

  2. It also depends on alternation of generations in most individuals {alternate between Sporothallus which is considering asexual cycle (2n) and Gametothallus sexual cycle (1n)}

  3. The haploid thallus, called the gametothallus, produces female and male gametes. These occur in pairs and are terminal and sub terminal. Male gametes are orange-colored, while female gametes are colorless. In addition, female gametes are much larger than male gametes

  4. The Diploid thallus is called the Sporothallus. The sporothallus produces two types of zoosporgia: zoosporgangium (meitosporangium) and resistant sporangium (meiosporangium)

  5. Zoosporangia produce diploid zoospores, which can function as a means of asexual reproduction. while meiosporangium produce haploid zoospore after suffering meiosis division , Sexual reproduction may be isogamous, anisogamous, or oogamous
• Ecological Role of Chytridiomycota

  • Decomposition and Nutrient Recycling
  • Aquatic Food Chains
  • Soil Health
  • Pathogens
• Chytrids are significant decomposers, breaking down complex organic matter such as dead plant material, and other detritus. They contribute to the process of nutrient cycling by releasing nutrients back into the environment, which can then be utilized by other organisms
• Chytrids serve as food sources for various organisms in aquatic ecosystems. Zoospores and other chytrid structures are consumed by protozoa, small invertebrates, and even some fungi, contributing to the transfer of energy through food chains. Chytrid zoospores are a good food source for zooplankton
• Chytrids play a role in soil health by contributing to the decomposition of organic matter and the formation of humus, a key component of soil organic matter. This helps maintain soil fertility and structure, which is essential for plant growth and ecosystem stability
• While not all chytrids are pathogens, some species can cause diseases in plants, algae, fungi, and animals. For example, Batrachochytrium dendrobatidis is a chytrid pathogen responsible for causing chytridiomycosis, a deadly disease affecting amphibians worldwide. Amphibian chytridiomycosis is an infectious fungal disease that can be fatal to amphibians. As the disease spread globally beginning in the 1970s, many populations declined greatly and species became extinct. This pandemic served as a first precedent for the threat of infectious diseases directly on biodiversity
• "External digestion"


  An organism secretes enzymes to decompose complex molecules into simple compounds outside of its body
• Enzymes


  • Glucosidases
  • Amylases
  • Glucoamylases