Lecture 6 - Fungi
Lecture 6 - Fungi October-05-12 10:37 PM
KEYWORDS: • Fungi: characteriscs • Fungal protists: oomycetes (disease), slime molds (plasmodial and cellular) • True fungi o Characteristics o Disease organisms: sclerotina, smut, cercospora, rust o Introduced disease (tree): elm, butternut, chestnut o Natural products: amanitine mushroom, aflatoxin, ear rot, LSD, magic mushroom, secondary metabolites o Fermentation products: biofuel from starch and cellulose o Divisions: Chytrids (chitridiomycetes), Bread mold (zygomycetes), Cup fungi and yeast (ascomycetes), Mushroom and rust (basidiomycetes) Fungi • • • •
70000 species Molds, mushrooms, disease organisms, yeasts Traditionally placed with plants but closer to animals Subgroup: fungal protists, collection of primitive organisms and some related to algal protists, but with fungal characteristics Fungal Protists • Similar to true fungi only in having spores and acting as parasites and decomposers, but closer to algae • Early name: phycomysedes • Water molds (oomycota) • Plasmodial slime molds (myxomycota) • Cellular silme molds (dictyosteliomycota) • Fungicides: like antibiotics that target chitin synthesis (difficult to control) Oomycetes (water molds) 700 species (aquatic and terrestrial) • Decomposers and parasites • Grow by hyphae without cross walls (non septate) o *Hyphae: thin cytoplasmic tubes, invades food substances and excrete enzymes to take nutrients o *Septate: septum is cross wall • Cellulose in cell wall (not chitin) • Reason why not controlled by fungicides • Centrioles (like animals) • Large thick oopore (zygote 2n) in sexual cycle and zoospore in asexual cycle Important in Plant Disease Organisms • Phytophthora: late blight of potato (caused Irish famine)
Plant breeders produced 2 kinds (low genetic base), like white one without metabolites • Pythium: damping off of cereals • Downey mildew in grapes o
Slime Molds Plasmodial (myxomycota) • 700 species (terrestrial) • Found on rotting logs (but can move, amoeba like?) • No cell wall • Reproduction by spores Cellular slime molds (dictysteliomycota) • 50 species of amoeba like organisms • Cellulose cell wall • Centrioles (like animals) • Experimental model of apoptosis True Fungi • Chitin in cell wall • Glycogen reserve • Reproduction by spores • Hetertrophic • No centrioles • Nuclear membrane in telophase • Growth by hyphae • Specialized hostorium in some o Hostarium*: excrete enzymes, turn plant cell into soup and absorb into fungi Importance: • Disease organisms • Natural products • Fermentation products Fungi Disease Organisms • Fungi are main killers of plants • Introduced diseases escapes plant disease Sclerotina: wilts on sunflower • Changes shape, once fallen makes it easier for fungi to take nutrients Ustialgo: smut on corn • Food delicacy in Mexico Cercospora: leafspot disease on soybean (phototoxic fungi) • Produces light activated secondary metabolites Rust on ash trees Diseases on trees (introduced): • Elm disease: due to Dutch (Chinese elm resistant to it because of coevolution)(cup fungi) • Butternut beech disease • Chestnut disease: due to chestnut blight (cup fungi)
Natural Products In chemical arms race with other organisms, fungi produce toxins, hallucinogens, drugs Fungi are among the most important source of biologically active natural products (medicine) • Amanitine mushrooms: edible and poisonous (shuts down ribosomes, no more proteins) • Aflatoxin: grows on peanuts, most carcinogenic natural product • Ear and root rot of corn (crops): vomitoxin, prevents ribosome production, causes slow growth rates, can get into animal feed • LSD: from ergot fungi (ergot fever) • Magic mushroom (psilicybe mexicana): used for religious purposes • Fungal secondary metabolites as drugs: cyclosporin, antirejection drug (immunosupressant) Fermantaion Products • Fermentation creates alcohol Starch --> ethanol • Alcohol containing gas fermented from corn • Burns cleaner • Cleans engine • In a factory cellulose --> glucose --> ethanol by yeast • Expensive, oil prices cheaper • Pretreatment --> 1. enzyme production 2. enzyme hydrolysis --> separation --> ethanol fermentation --> distillation --> cellulose ethanol • Leftover fibre burned for electricity Division of True Fungi Chytrids (Chritidiomycetes) • 700 species (aquqatic) • Usually unicellular • Motile zoospores and gametes with flagella (distinguishing) • Most primitive from which fungi evolved • Responsible for worldwide decline of frogs Bread molds (Zygomycetes) • 1060 species (terrestrial saprophytes) • Few septa in hyphae • Distinctive life cycle with zygospore* • Includes genus Glomus (major mycorrhizae fungal symbiont) • symbiotic with roots of plants in agriculture • Life cycle* Cup fungi (Ascomycetes) • 3200 species • Serious plant diseases (chesnut, elm) • Septa in hyhae • Distinctive ascus (cup) • Truffles morels, blue molds (penicillin) o Truffle: fungus on oak tree
• • • •
Some edible Unicellular = yeasts Bread and brewer yeast (Saccharomyces cerevisae) Life cycle* Mushrooms and rusts (Basidiomycetes) • 16000 species • Decomposers of plant litter • Some symbionts in mycorrhizae • Ruts and smuts mostly parasitic on living plants and cause economic damage to cereals • Rust have complex life cycle with 2 hosts • Basidio: club • Clamp connection and life cycle* Importance: • Edible, toxic, and exotic species • Hallucinogens important in Americas (spiritual) • Medicinal: immunostimmulant species that improve resistance against disease (shitake, rischi, chaga)
KEYWORDS: • Fungi: characteriscs • Fungal protists: oomycetes (disease), slime molds (plasmodial and cellular) • True fungi o Characteristics o Disease organisms: sclerotina, smut, cercospora, rust o Introduced disease (tree): elm, butternut, chestnut o Natural products: amanitine mushroom, aflatoxin, ear rot, LSD, magic mushroom, secondary metabolites o Fermentation products: biofuel from starch and cellulose o Divisions: Chytrids (chitridiomycetes), Bread mold (zygomycetes), Cup fungi and yeast (ascomycetes), Mushroom and rust (basidiomycetes) Fungi • • • •
70000 species Molds, mushrooms, disease organisms, yeasts Traditionally placed with plants but closer to animals Subgroup: fungal protists, collection of primitive organisms and some related to algal protists, but with fungal characteristics Fungal Protists • Similar to true fungi only in having spores and acting as parasites and decomposers, but closer to algae • Early name: phycomysedes • Water molds (oomycota) • Plasmodial slime molds (myxomycota) • Cellular silme molds (dictyosteliomycota) • Fungicides: like antibiotics that target chitin synthesis (difficult to control) Oomycetes (water molds) 700 species (aquatic and terrestrial) • Decomposers and parasites • Grow by hyphae without cross walls (non septate) o *Hyphae: thin cytoplasmic tubes, invades food substances and excrete enzymes to take nutrients o *Septate: septum is cross wall • Cellulose in cell wall (not chitin) • Reason why not controlled by fungicides • Centrioles (like animals) • Large thick oopore (zygote 2n) in sexual cycle and zoospore in asexual cycle Important in Plant Disease Organisms • Phytophthora: late blight of potato (caused Irish famine)
Plant breeders produced 2 kinds (low genetic base), like white one without metabolites • Pythium: damping off of cereals • Downey mildew in grapes o
Slime Molds Plasmodial (myxomycota) • 700 species (terrestrial) • Found on rotting logs (but can move, amoeba like?) • No cell wall • Reproduction by spores Cellular slime molds (dictysteliomycota) • 50 species of amoeba like organisms • Cellulose cell wall • Centrioles (like animals) • Experimental model of apoptosis True Fungi • Chitin in cell wall • Glycogen reserve • Reproduction by spores • Hetertrophic • No centrioles • Nuclear membrane in telophase • Growth by hyphae • Specialized hostorium in some o Hostarium*: excrete enzymes, turn plant cell into soup and absorb into fungi Importance: • Disease organisms • Natural products • Fermentation products Fungi Disease Organisms • Fungi are main killers of plants • Introduced diseases escapes plant disease Sclerotina: wilts on sunflower • Changes shape, once fallen makes it easier for fungi to take nutrients Ustialgo: smut on corn • Food delicacy in Mexico Cercospora: leafspot disease on soybean (phototoxic fungi) • Produces light activated secondary metabolites Rust on ash trees Diseases on trees (introduced): • Elm disease: due to Dutch (Chinese elm resistant to it because of coevolution)(cup fungi) • Butternut beech disease • Chestnut disease: due to chestnut blight (cup fungi)
Natural Products In chemical arms race with other organisms, fungi produce toxins, hallucinogens, drugs Fungi are among the most important source of biologically active natural products (medicine) • Amanitine mushrooms: edible and poisonous (shuts down ribosomes, no more proteins) • Aflatoxin: grows on peanuts, most carcinogenic natural product • Ear and root rot of corn (crops): vomitoxin, prevents ribosome production, causes slow growth rates, can get into animal feed • LSD: from ergot fungi (ergot fever) • Magic mushroom (psilicybe mexicana): used for religious purposes • Fungal secondary metabolites as drugs: cyclosporin, antirejection drug (immunosupressant) Fermantaion Products • Fermentation creates alcohol Starch --> ethanol • Alcohol containing gas fermented from corn • Burns cleaner • Cleans engine • In a factory cellulose --> glucose --> ethanol by yeast • Expensive, oil prices cheaper • Pretreatment --> 1. enzyme production 2. enzyme hydrolysis --> separation --> ethanol fermentation --> distillation --> cellulose ethanol • Leftover fibre burned for electricity Division of True Fungi Chytrids (Chritidiomycetes) • 700 species (aquqatic) • Usually unicellular • Motile zoospores and gametes with flagella (distinguishing) • Most primitive from which fungi evolved • Responsible for worldwide decline of frogs Bread molds (Zygomycetes) • 1060 species (terrestrial saprophytes) • Few septa in hyphae • Distinctive life cycle with zygospore* • Includes genus Glomus (major mycorrhizae fungal symbiont) • symbiotic with roots of plants in agriculture • Life cycle* Cup fungi (Ascomycetes) • 3200 species • Serious plant diseases (chesnut, elm) • Septa in hyhae • Distinctive ascus (cup) • Truffles morels, blue molds (penicillin) o Truffle: fungus on oak tree
• • • •
Some edible Unicellular = yeasts Bread and brewer yeast (Saccharomyces cerevisae) Life cycle* Mushrooms and rusts (Basidiomycetes) • 16000 species • Decomposers of plant litter • Some symbionts in mycorrhizae • Ruts and smuts mostly parasitic on living plants and cause economic damage to cereals • Rust have complex life cycle with 2 hosts • Basidio: club • Clamp connection and life cycle* Importance: • Edible, toxic, and exotic species • Hallucinogens important in Americas (spiritual) • Medicinal: immunostimmulant species that improve resistance against disease (shitake, rischi, chaga)
