Introduction of FungiThey are classified as eukaryotes,Fungi can be divided into two basic morphological forms,yeasts and hyphae Yeasts are unicellular fungi which reproduce asexually by blastoconidia formation (budding) or fissionHyphae are multi-cellular fungi which reproduceasexually and/or sexually
Most fungi occur in the hyphae form as branching,threadlike tubular filaments. - lack cross walls (coenocytic) - have cross walls (septate) - clamp connections at the septa which connect the the hyphae elements.Coenocytic hyphae Septated Hyphae
COMMON CHARACTERISTICS OF FUNGI1. Heterotrophy - other food. There are three major categories ofheterotrophs, which include the saprophytes, symbionts, and parasites.Saprophytes (feed on dead tissues or organic waste); symbionts (mutuallybeneficial relationship between a fungus and another organism); parasites(feeding on living tissue of a host). Parasites that cause disease are calledpathogens. Some parasites are obligate parasites (require a living host tosurvive), while others are facultative or nonobligate parasites (do notrequire a living host in order to survive).2. Body formunicellularfilamentous (tube-like strands called hypha (singular) or hyphae (plural).mycelium = aggregate of hyphaesclerotium = hardened mass of mycelium that generally serves as anoverwintering stage.multicellular, such as mycelial cords, rhizomorphs, and fruit bodies(mushrooms)
3. Fungus is often hidden from view. It grows through itsfood source (substratum), excretes extracellular digestiveenzymes, and absorbs dissolved food.4. Indeterminate growth.5. Spores - asexual (product of mitosis) or sexual (productof meiosis) in origin. Purpose of Spores (a) Allows the fungus to move to new food source. (b) Resistant stage - allows fungus to survive periods of adversity. (c) Means of introducing new genetic combinations into a population.6. Vegetative phase of fungus is generally sedentary.7. Cell wall present, composed of cellulose and/or chitin.
8. Food storage - generally in the form of lipids andglycogen.9. Eukaryotes - true nucleus and other organellespresent.10. All fungi require water and oxygen (no obligateanaerobes).11. Fungi grow in almost every habitat imaginable, aslong as there is some type of organic matter present andthe environment is not too extreme.12. Diverse group, number of described species is about69,000 (estimated 1.5 million species total).
Phylums of Fungi ►Phylum Zygomycota - common mold found on land ► Reproduce by zygospores Ex: Rhizopus - common bread mold Contain root-like structures (rhizoids) to anchor in bread. Stolons on surface of bread.
PHYLUM CHARACTERISTICSA. ASEXUAL REPRODUCTION:Sporangiospores (aplanospores) or modified sporangia (sac-like merosporangia) functioning as conidia.B. SEXUAL REPRODUCTION:Two morphologically similar gametangia fuse to produce a warty, thick zygospore. Meiosis within zygospore.C. VEGETATIVE HYPHAE:Haplophase; no dikaryophase except in fused gametangia; aseptate.
Asexual Reproduction: Sexual Reproduction:-spores are produced by -two opposite mating types ofsporangia at the ends of hyphae join to produce gametangiamodified, erect hyphae that produce a diploid zygospore (thick walled spore) -the zygospore undergoes meiosis before germination and produces a haploid mycelium
D. CELL WALLS: Chitin and chitosan.E. ECOLOGY: Free-living to parasitic. Free-livingforms mainly terrestrial saprobes. Parasites mainlyof insects, but of other animals, too. Some parasiticon microbial eukaryotes.
CLASS ZYGOMYCETESproduction of asexual aplanospores,• fusion of gametangia to produce zygospores• walls of chitin and chitosan;• asexual development seems to be from many-spored sporangia, through sporangia with a much-reduced number of spores,• to one-spored sporangiola which function asconidia.
ORDER MUCORALES- Filamentous;- aplanospores produced in globose,- multinucleate sporangia,- narrow cylindrical sac-like merosporangia,- few-spored sporangiola or singly as conidia;- zygospores often thick-walled,- black and warty resting spores;- large terminal chlamydospores common in mycorrhizal forms.- Saprophytic "pin molds".
ORDER ENDOGONIALES- Filamentous- coenocytic- saprobic and mycorrhizal- zygospores produced inunderground sporocarp.Densospora , Endogone, Pteridiospora,Sclerogone, Youngiomyces.
ORDER DIMARGARITALES- Filamentous- hyphae with septa which have a lens-shaped cavity;- asexual reproduction by merosporangium of bispores.- Zygospore ornamented.- Parasites of fungi, especially Mucorales.Dimargaris, Dispira, Spinalia, Tieghemiomyces.
ORDER ENTOMOPHTHORALES- Filamentous- some saprophytic, but mostly insect parasites- vegetative phase tending to break up into segments (hyphal bodies)- asexual reproduction by forcibly discharged uni- or multinucleate conidia- zygospores smooth or ornamented.Entomophthora, Condiobolus, Completoria,Meristacrum, Neozygites..
Basidiomycota Club fungiTilletia controversa Gymnosporangium juniperi-virginianae Amanita rubrovaginata
Basidiomycota- Basidiomycetes - the club fungi, about 22,300 species3. Includes mushrooms, toadstools, puffballs, shelf fungi, rusts, birds nest fungi and smuts2. Characterized by perforate septate hyphae and the production of a basidium (club) following sexual reproduction. The basidia (pl. of basidium) occur in a mycelium called a basidiocarp and they produce external basidiospores3. See your next slide for a typical life cycle
Basic structure of Club fungi cap Vulva Gills Annulus Stalk