Classification of Fungi: A Taxonomic Overview

1. Taxonomy a classification of organisms into groups based on similarities of structure or origin etc.

2. KINGDOM CHARACTERISTIC EXAMPLE Monera Prokaryocyte Bacteria Actinomyces Protista Eukaryocyte Protozoa Fungi Eukaryocyte * Fungi Plants Eukaryocyte Plants Moss Animals Eukaryocyte * Arthropods Mammals Man

3. KINGDOM CHARACTERISTIC EXAMPLE Monera Prokaryocyte Bacteria Actinomyces Protista Eukaryocyte Protozoa Fungi Eukaryocyte * Fungi Plants Eukaryocyte Plants Moss Animals Eukaryocyte * Arthropods Mammals Man

4. Classification of Fungi • Kingdom Fungi • Division -mycota • Subdivision -mycotina • Class -mycetae • Subclass -mycetes • Order -ales • Family -aceae • Genus -------- • Species --------

6. Classification of Fungi • Four major division of fungi, base on the type of sexual spores (ascospore, basidiospore, zygospore, oospore), plus another group, which have no know sexual state. • Chytridiomycota • Zygomycota • Ascomycota • Basidiomycota • Deuteromycota (Imperfect fungi)

7. asci basidia zygosporangia Classification & Phylogeny motile spores

8. Chytridiomycota – “chytrids” • Simple fungi • Produce motile spores - zoospores • Mostly saprobes and parasites in aquatic habitats • Could just as well be Protists Chytridium growing on spores Chytriomyces growing on pine pollen

9. ‘Chytrids’ are considered the earliest branch of the true fungi (Eumycota) • Cell walls contain chitin and glucan • Only true fungi that produce motile, flagellated zoospores – Usually single, posterior whiplash type – Some species have multiple flagella • Zoospore ultrastructure is taxonomically important within this phylum • Commonly found in soils or aquatic environments, chytrids have a significant role in degrading organics

10. A few are obligate intracellular parasites of plants, algae, and small animals (e.g., frogs) • Very few economically important species (Synchytriumendobioticumcauses potato wart disease) • More important (and fascinating) as biological models (e.g, Allomyces).

11. Zygomycota – “zygote fungi” Rhizopus on strawberries • Sexual Reproduction - zygosporangia • Asexual reprod. – common (sporangia – bags of asexual spores) • Hyphae have no cross walls • Grow rapidly • Decomposers, pathogens, and some form mycorrhizal associations with plants Rhinocerebral zygomycosis

12. Five features of Phylum Zygomycota – Cell walls contain chitin, chitosan, and polyglucuronic acid – Some members typically bear multinucleate, coenocytichyphae, i.e., without cross walls (septa; sing., septum) • When present, septa are simple partitions • Some Orders have regular septations that are flared having a centrally plugged pore – Produce zygospores (meiospore).

13. – Asexual spores (mitospores), termed sporangiospores, form through cytoplasmic cleavage within a sac-like structure termed a sporangium – Haploid genome • Importance of the zygomycetous fungi – Organic degraders/recyclers – Useful in foodstuffs/fermentations – Pathogens of insects/other animals • Generalized life cycle – Asexual stage (anamorphic; imperfect) • A thin-walled sac (sporangium) is walled off at the tip and fills with cytoplasm

14. • containing multiple nuclei (with collumella underneath sac) • Cytoplasmic cleavage and separation of nuclei into walled units produces sporangiospores • Thin sporangial wall (peridium) breaks releasing sporangiospores • Sporangiospores germinate to repeat the asexual life cycle

15. The zygospore represents the teleomorphic phase (sexual; perfect form) of this phylum – Results from the fusion of gametangia of heterothallic (two different mating types; designated “+” and “-”) or homothallic (self fertile) strains

16. – Acts as a thick-walled resting spore • Zygosporangium becomes thick walled to form the zygospore • Hyphae to the sides become empty appendages (suspensor cells) • Zygospore often forms ornate appendages • Zygospore is constitutively dormant for a time, but then germinates to produce a sporangium containing haploid sporangiospores

17. Sexual zygsporangium with one zygospore Asexual sporangium with spores inside Life cycle of Rhizopus

18. Ascomycota – “sac fungi” • Sexual Reproduction – asci (sing. = ascus) • Asex. Reprod. – common • Cup fungi, morels, truffles • Important plant parasites & saprobes • Yeast -Saccharomyces • Decomposers, pathogens, and found in most lichens A cluster of asci with spores inside

19. Life cycle of Ascomycetes

20. Apothecium Perithecium - Perithecium - Apothecium - Cleistothecium Ascocarp Cleistothecium

21. Basidiomycota – “club fungi” • Sexual Reproduction – basidia • Asexual reprod – not so common • Long-lived dikaryotic mycelia • Rusts & smuts –plant parasites • Mushrooms, polypores, puffballs, boletes, bird’s nest fungi • Enzymes decompose wood, leaves, and other organic materials • Decomposers, pathogens, and some form mycorrhizal associations with plants SEM of basidia and spores

22. Clamp connection

23. Life cycle of basidiomycetes

24. Some fungi have more than one scientific name – Why? • Teleomorph: the sexual reproductive stage (morph), typically a fruiting body (e.g., Morchellaesculenta, Agaricusbrunescens). • Anamorph: an asexual reproductive stage (morph), often mold-like (e.g. Aspergillusflavus, Fusariumsolani). • Holomorph: the whole fungus, including all anamorphs and the teleomorph.

25. Deuteromycota – Form Phylum “Imperfect Fungi” • Fungi that seldom or never reproduce sexually. • Asexual reproduction by vegetative growth and production of asexual spores common.

26. HUMAN-FUNGUS INTERACTIONS • Beneficial Effects of Fungi • Decomposition - nutrient and carbon recycling. • Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e.g., fermented products, mushrooms). • Model organisms for biochemical and genetic studies. • Harmful Effects of Fungi • Destruction of food, lumber, paper, and cloth. • Animal and human diseases, including allergies. • Toxins produced by poisonous mushrooms and within food (e.g., grain, cheese, etc.). • Plant diseases.