microconidia

Microconidia are a type of asexual spore (conidium) produced by some fungi. They are generally smaller than macroconidia and serve as a means of rapid asexual reproduction and dispersal.

Morphology and development: Microconidia are typically unicellular and may be ellipsoidal, spherical, or ovoid in shape. They are produced on specialized hyphae called conidiophores by conidiogenous cells such as phialides or annellides. The arrangement can be solitary, in clusters, or in short chains, depending on the species. In many dermatophytes and other pathogenic fungi, microconidia are the dominant or characteristic conidia.

Ecology and function: Microconidia occur in a variety of ecological niches, including soil, plant material, and animal or human-associated environments. They enable rapid propagation and dissemination under favorable conditions and may participate in infection or colonization when disseminated to susceptible hosts.

Taxonomic and diagnostic relevance: In diagnostic mycology, the presence and morphology of microconidia aid in identifying fungal genera and species, often in combination with the pattern of macroconidia, colony morphology, and growth characteristics. Genera known to produce microconidia include several species of Aspergillus, Fusarium, and dermatophytes, among others.

Limitations: Microconidia are not universal to all fungi and can vary widely in size, shape, and formation mode. The term describes one class of conidia alongside macroconidia, chlamydospores, and other propagules. See also conidium and conidiogenesis for related concepts.