320-1 Learning Targets What are the characteristics of Fungi? What is the internal structure of a fungus?How do fungi reproduce?
4Fungi Characteristics VERY different from plants:No roots, stems or leavesHave no chlorophyllEukaryotic heterotrophs with cell wallsCell wall made of CHITINDigest food outside of body and THEN absorb it through cell wallSome absorb nutrients from decaying matterCalled Detritus FeedersExample of Detritus feeder: Club fungi/mushroomsSome live as parasitesExample of Parasitic feeder: Ring wormSome live in symbiotic relationship that benefits both sides
6More Characteristics All fungi are multicellular (except yeast) Multicellular fungi are made of tiny filaments called hyphaeHyphae tangle together in a thick mass to form the mycelium or fungal bodyMycelium lies below the ground and the fruiting body or reproductive structure is above ground (the “mushroom”)
7Hyphae Nuclei Cell wall Cytoplasm Cross wall Hyphae With Cross Walls Hyphae Without Cross Walls
10Fairy Rings Some mycelia can live for many years Over time, the nutrients at the center of the mycelium become depletedNew mushrooms only sprout at the edges of the mycelium, causing a ringCalled a “FAIRY RING”
11Reproduction in Fungi Fungi reproduce both sexually and asexually Fungi are classified according to their structure and method of reproductionGeneral Groups:Common MoldsSac FungiClub FungiImperfect Fungi
12are divided into the phyla Fungiare divided into the phylaAscomycotaZygomycotaBasidiomycotaDeuteromycotaincludesincludesincludesincludesCommon moldsSac fungiClub fungiImperfect fungi
13What are the characteristics of the four major phyla of Fungus? 20-2 Learning TargetsWhat are the characteristics of the four major phyla of Fungus?
15Common Molds Phylum Zygomycota: called zygomycetes Common molds that grow on meat, cheese and breadBest Known Zygomycete:Rhizopus stolonifer (black bread mold)StructureThe mycelium is the cottony white mass of a bread mold.The black balls at the top of the filaments are called SPORANGIA or spore cases.This fungus sends out filaments across the top of the bread.These filaments secrete digestive enzymes and absorb the digested food externally
17Rhizopus Reproduction Rhizopus reproduces asexually by spore formationEach spore has a nucleus and is surrounded by a black wall.The outer wall of the sporangium is very delicate and easily torn.When torn, the exposed spores are quickly carried away by airThe spores then grow and reproduce on a moist surface.The mold also reproduces sexuallyWe will not learn this process in detail, you just need to know that it is possible!
18Rhizopus Life Cycle FERTILIZATION Sporangium Gametangia Spores (N) Zygospore (2N)Spores (N)Sporangium+ Mating type (N)StolonsRhizoids- Mating type (N)SporangiophoreGametangiaFERTILIZATIONMEIOSISSexual ReproductionAsexual ReproductionDiploidHaploid
19Sac Fungi Phylum Ascomycota: called Ascomycetes Named for the ASCUS, their reproductive structure that contains sporesLargest Phylum of Kingdom FungiSome ascomycetes such as cup fungi are visible on the ground, others like yeasts are microscopicEXAMPLES: Morels, Truffles
20YEASTYeast are unicellular fungi used by humans for baking and brewingCause bread to rise by producing CO2 in fermentationThey can reproduce sexually and form ascosporesThey reproduce asexually by buddingA bulge appears on the cell wall.The nucleus splits and moves into the bulge.The bulge grows but may remain attached to the mother cell.Chains grow and may eventually break.
22Club Fungi Phylum Basidiomycota: called basidiomycetes or club fungi Gets name from reproductive structure that resembles a club (called a basidium)The cap of the basidiomycete (like a mushroom) is made of tightly packed hyphaeThe lower side of the cap is made of GILLSGills are thin blades of tissue lined with cells that produce sporesSpores are scattered to produce more mushroomsExamples: Mushrooms, Shelf Fungi, Puffballs, Earthstars, jelly fungi
23Basidiomycete Life Cycle Fruiting body (N + N)ButtonSecondary mycelium (N + N)Primary mycelium (N)+ Mating type (N)- Mating type (N)Basidiospores (N)Zygote (2N)Basidia (N + N)Gills lined with basidiaGillsStalkBaseCapFERTILIZATIONHYPHAE FUSEHaploidDiploidMEIOSIS
24Basidiomycete Pictures PuffballsShelf Fungi: form next to dead/decaying trees
25Stinkhorns Stinkhorns are a family of basidiomycetes They produce a foul-scented mushroomTheir method of reproduction is different than most mushrooms, which use the air to spread their sporesStinkhorns produce a sticky spore mass on their tip which has an odor that attracts fliesThe flies land on the stinkhorn and collect the spores on their legs and carry it to other locations.
27Just a WarningMany types of fungi are delicacies and are cultivated for food (Portabellas are yummy!)Many wild mushrooms are also edible, BUT many are POISONOUSMany species of edible mushrooms look identical to poisonous mushroomsMoral of the Story: Don’t pick and eat mushrooms unless you know what you are doing!
29Imperfect FungiPhylum Deuteromycota: called deuteromycetes or imperfect fungiExtremely diverse group– basically the misfit fungiFungi go here when researchers have not found a sexual phase in their life cyclesEXAMPLES: Penicillium, Ringworm, Athlete’s Foot
30PenicilliumPenicillium is mold that grows on fruit and is source of antibioticUP CLOSE!!!Mold on an orange
31Importance of Fungi FOOD SOURCE MEDICINES: Mushrooms Morels – a delicacyYeast – used in baking and fermentationTruffles – very expensive delicacyMEDICINES:Penicillin – from PenicilliumCyclosporin – anti-rejection drug
36Importance of Fungi IN NATURE: Decompose and recycle detritus. Lichens – symbiotic relationship between a fungus and algae (see p. 540)Usually neither can grow on their ownCan grow in harsh environments due to relationship (fungus gets water, minerals, and other carries out photosynthesis)Mycorrhizae –symbiotic relationships between plants and fungiFungus helps obtain more nutrients by increasing surface area (plant also provides nutrients)About 90% of plants have a miycorrhizal relationshipFungi kill nematodes – a roundworm that attacks crops