Fungal Spores, Spore Dormancy, and Spore Dispersal

Fungal Spores, Spore Dormancy, and Spore Dispersal

• Fungal Spores Overview

  • Fungi are exceptional spore-producing organisms.
  • Produce millions of spores with diverse shapes and sizes.
  • Spores can be dormant during environmental changes.

• Types of Fungal Spores

  • Asexual Spores
  • Vary from class to class.
  • Types include:
    • Zoospores (Mastigomycetes)
    • Sporangiospores (Zygomycetes)
    • Conidia (Ascomycetes)
    • Basidiospores (Basidiomycetes)
    • Conidia or conidiospores (Deuteromycetes).

Mastigomycotina

• Overview

  • Includes classes such as Chytridiomycetes and Oomycetes.

• Class Chytridiomycetes

  • Characterized by asexual zoospores with a single posterior flagellum.
  • Example: Synchytrium endobioticum causes Potato Wart Disease.

• Class Oomycetes

  • Known for severe plant diseases like potato late blight and downy mildew.
  • Produce biflagellated zoospores in zoosporangia.
  • Economic impact includes pathogens like Phytophthora infestans.

Zygomycotina

• Class Zygomycetes

  • Common genera include Mucor and Rhizopus (Bread Mold).
  • Asexual reproduction through sporangiospores in sporangia.
  • Sexual reproduction involves the fusion of hyphae, forming zygosporangium giving rise to zygospores.

• Rhizopus stolonifer

  • Coenocytic mycelia, reproduces asexually.
  • Forms sporangiospores within sporangia, which are dispersed.

Ascomycotina

• Class Ascomycetes (Sac Fungi)

  • Largest phylum of fungi, important for food and medicine.
  • Notable fungi include Penicillium and Saccharomyces (yeast).
  • Causes significant plant diseases and produces economically important compounds.

• Asexual & Sexual Reproduction

  • Asexual spores called conidia produced on conidiophores.
  • Sexual reproduction leads to the formation of asci in ascocarps, producing ascospores.

Basidiomycotina

• Overview

  • Includes mushrooms, puffballs, and wood-decaying fungi.
  • Features club-shaped basidia for reproduction.

• Life Cycle

  • Basidiospores are produced from the fusion of nuclei in basidia.
  • Asexual reproduction may occur through budding or conidia.

Deuteromycotina (Fungi Imperfecti)

• Characteristics
  • Classified by asexual reproduction only (conidia).
  • Includes species used in industry for antibiotics and food production.

Fungal Spore Dispersal

• Mechanisms of Dispersal

  • Zoospores can act as vectors for plant viruses.
  • Airborne spores dispersed by wind or rain.
  • Factors affecting spore fate include sedimentation, impaction, and washout.

• Air Sampling and Health

  • The respiratory tract of humans captures many fungal spores.
  • Health implications include allergies and infections by pathogenic fungi like Aspergillus and Candida.

• Air Sampling Devices

  • Rotorod sampler: experimental air-sampling.
  • Burkard spore sampler: continuous monitoring.
  • Anderson sampler: simulates human respiratory deposition.

References

• Fungal Biology JW Deacons; Introduction to Mycology-CJ Alexopoulos; Microbiology Fundamentals-Cowan; etc.