Ascomycetes vs Basidiomycetes
Fungi are a wide group of organisms that have a big influence on ecology and human health. They are considered as important decomposers and disease- causing organisms. Fungi are found everywhere including both terrestrial and aquatic environments. The reproduction of them may occur either by sexual or asexual methods. Also, they show some unusual pattern of mitosis which cannot be seen in other organisms. Mycologists believe that there are as many as 1.5 million fungal species that exist either as single-celled yeasts or in multicellular forms with several cell types. To understand the fungal phylogeny, mycologists have divided the group into seven monophyletic phyla, namely; Microsporidia, Blastocladiomycota, Neocallismastigomycota, Chytridiomycota, Glomeromycota, Basidiomycota, and Ascomycota. Out of these seven groups, Ascomycota and Basidiomycota are considered as the two largest phyla which include macro fungi.
Ascomycetes
About 75% of the known fungi are considered as Ascomycetes, including bread yeasts, common molds, morels, cup fungi, and truffles. Some plant pathogens such as chestnut blight, Cryphonecteria parasitica and Ophiostoma ulmi, and Penicillium are also considered as ascomycetes. Ascomycetes are important as a source of antibiotics, decomposer organisms and disease causing organism. They have characteristic sexual reproduction structures known as ascus, where the karyogamy is taken place.
Figure 1: Sexual and Asexual reproduction cycles of ascomycetes
( Source:http://www.aber.ac.uk/fungi/fungi/taxonomy.htm)
Ascus contains the ascospores and is formed by heterokaryotic hyphae. Asexual reproduction is also very common in ascomycetes. It occurs by mitotically derived spores known as conidia, or by budding (in yeast).
Basidiomycetes
Basidiomycetes are commonly known as club fungi. They include some of the most familiar fungi such as mushrooms, toadstools, puffballs, jelly fungi, shelf fungi, and some plant pathogens including rusts and smuts. They have characteristic sexual reproductive structure called basidium, which is club-shaped, and it’s the place where karyogami or fusion of two nuclei occurs.
Figure 2: Sexual reproduction of Basidiomycetes
(Source: http://www.aber.ac.uk/fungi/fungi/taxonomy.htm#ba)
Meiosis occurs immediately after karyogami resulting four haploid products, which are incorporated into basidiospores. In many species of this phylum, Basidiospores are borne at the end of the basidia on sterigmata.
What is the difference between Ascomycetes and Basidiomycetes?
• Characteristic reproduction structure of ascomycetes is ascus, whereas that of basidiomycetes is basidium.
• Acetomycetes include more known fungi species than basidiomycetes.
• In basidiomycetes, spores are produced externally attached to basidium whereas, in ascomycetes, spores are produced internally within the ascus.
• In basidiomycetes, basidia are attached to basidiocarp whereas, in ascomycetes, asci are attached to ascocarp.
• Spores of basidiomycetes are called basidiospores. In contrast, ascomycetes can produce both conidia and ascuspores as their spores.
• Unlike the basidiomycetes, ascomycetes have single-celled fungal species called yeast.
• In basidiomycetes, sexual reproduction is present while, in ascomycetes, both sexual and asexual reproduction methods are present.