Fungi have five main phyla.
Firstly, Chytridiomycota also called chytrids. Do not have mitochondria in their cells and produce motile spores with flagella, which move through water. They used to be classified as protists, but modern DNA analysis techniques have redefined them as fungi. Some of them are anaerobes and live symbiotically inside the digestive tracts as large herbivores. Some of the anaerobic chytrids also dwell in landfill sites, where they help to decompose matter. The oldest known living organism is a large chytrid fungus, whose underground mycelium covers over 900 hectares; the whole organism is 9,000 years old.
Secondly, Zygomycota also called pin moulds. The moulds that you may find growing on fruit or cheese kept for too long in the fridge. Some are zygote-forming mycorrhizae (fungi that live symbiotically inside plant roots and play an important role in aiding uptake of minerals by the plant). Zygomycota are mostly microscopic.
Their spores form in round-shaped spore cases called sporangia. Thirdly, Ascomycota is a ‘sac’ like fungi. The sac fungi produce spores for reproduction in a sac-like structure, called an ascus. Cup fungi include morels, truffles and some mushrooms.
The ascomycete Botrytis cinerea (Figure 15) infects many crop plants and soft fruits. Aspergillus niger (Figure 16) causes black mould of onions and some ornamental plants, but is also used within the food and biotechnology industries as a source of enzymes. Aspergillus species can infect humans, causing ear and lung infections. Penicillium spp. are a source of the antibiotic penicillin. Fusarium graminearum infects cereal crop plants. Basidiomycota also called ‘club’ fungi, is the fourth type of fungi phyla. They include many types of mushrooms, toadstools, puffballs and stinkhorns.
The visible parts of these fungi are the fruiting bodies that appear above ground. They produce spores in a club-shaped spore case called a basidium. Rust fungi, major pathogens of cereal crops, are basidiomycetes. Lastly, Glomeromycota. Members of this division of fungi form mycorrhizae in the roots of land plants.
These mycorrhizae increase the uptake of minerals by the plants. This symbiotic association has been around for about 400 million years.