Fungal reproduction

Question 1

intro - diverse reproductive strategies

Answer 1

Fungi exhibit diverse reproductive strategies—asexual, sexual, and parasexual—that ensure survival, adaptation, and genetic diversity. Most fungi have haploid-dominant life cycles, and spore production plays a central role in their propagation and dispersal.

Question 2

2nd para - Asexual reproduction

Answer 2

Asexual reproduction occurs via mitosis, producing genetically identical spores such as conidia (in Ascomycota) or sporangiospores. In ascomycetes like Aspergillus, conidia form on conidiophores through septation and mitotic division of hyphae. Yeasts such as Saccharomyces cerevisiae reproduce similarly by budding. While asexual reproduction is less common in Basidiomycota, some species produce conidia or reproduce via budding in yeast-like forms (e.g., Malassezia).
These spores are often highly resilient and adapted for dispersal, allowing fungi to colonise new environments rapidly.

Question 3

3rd para - sexual reproduction

Answer 3

Sexual reproduction in fungi consists of three key stages: plasmogamy (cytoplasmic fusion), karyogamy (nuclear fusion), and meiosis (to restore the haploid state and generate genetic diversity). These processes lead to the formation of specialised reproductive structures that vary significantly between fungal phyla.

Question 4

4th para - parasexual reproduction

Answer 4

The parasexual cycle offers an alternative recombination route in fungi that lack or rarely undergo sexual reproduction. It begins with anastomosis—fusion between genetically distinct hyphae—creating a heterokaryon. Occasionally, haploid nuclei fuse to form diploid nuclei, which undergo mitotic division. Subsequent chromosome loss (haploidisation) restores haploidy and creates novel genotypes. This process is especially relevant in industrial or pathogenic fungi where meiotic sexual cycles may be suppressed.

Question 5

5th para - ascomycota reproductive featuers

Answer 5

Ascomycota are defined by the formation of sexual spores in sac-like structures called asci, usually housed within a fruiting body known as an ascocarp. Sexual reproduction involves plasmogamy between an antheridium (male) and ascogonium (female), joined by a trichogyne. This results in a dikaryotic mycelium that develops into the ascocarp. Within the asci, karyogamy occurs, followed by meiosis and a round of mitosis, yielding typically eight ascospores. Asexual reproduction occurs via conidiophores, which produce conidia by septation and mitosis on the haploid thallus.

Question 6

6th para - basidiomycota reproductive features

Answer 6

Basidiomycota are characterised by the formation of sexual spores on the outside of club-shaped cells called basidia, typically located on a large fruiting body called a basidiocarp. Fusion of compatible haploid mycelia results in a long-lived dikaryotic mycelium, which dominates the life cycle. In each basidium, karyogamy is followed by meiosis, producing four haploid basidiospores that bud externally. Although sexual reproduction predominates in this phylum, some species can also reproduce asexually through conidia or yeast-like budding.