Kingdom Fungi Finding the Fungus Among Us

Characteristics of Fungi Eukaryotic Most are Multicellular Filamentous body plan Heterotrophic by Absorption Produce spores by sexual and asexual reproduction Haploid for part or most of life cycle Cell wall made of chitin No movement: change location by growth of body or dispersion of spores

The Filamentous Body of a Fungus (c) Hyphal Cells (cutaway) (a) Mycelium Haploid Nuclei Cytoplasm (a) A fungal mycelium spreads over decaying vegetation. The mycelium is composed of (b) a tangle of microscopic hyphae, only one cell thick, (c) portrayed in cross section to show their internal organization. Septum (b) Individual Hyphae Pore Cell Walls

Body Plan of Fungi Mycelium = network of filaments Hypha = individual filament (plural = hyphae) Septum = partition dividing cells, has pore for distribution of nutrients Reproductive structure extends from main body, produces spores

Fungal Nutrition Heterotropic by absorption Three nutritional modes secrete digestive enzymes digest macromolecules outside the body absorb digested nutrients Three nutritional modes Saprophytic = digestion of dead organisms Parasitic = digestion of live organisms, causing disease Mutualistic = beneficial relationship for two independent organisms

Saprophytes Fungus on pinecone, Soil fungus between soy seedlings, woodrot

Parasites Clockwise from top right: Athlete’s foot fungus, affected feet, candida, ringworm, ergot, corn smut

Lichen: Mutualism Between Alga and Fungus Algal Layer Fungal Hyphae Attachment Structure

Mycorrhizae: Mutualism Between Fungus and Plant Roots

Applying Your Knowledge Parasitic Saprophtyic Mutualistic Which mode of nutrition Provides a benefit for the fungus and its symbiotic partner? Is shown by athlete’s foot fungus? Involves digestion of dead organisms?

Sexual Reproduction Hypha from mycelia of opposite mating types fuse Fusion of two haploid nuclei forms diploid zygote Zygote produces haploid spores by meiosis Each spore germinates to produce a haploid mycelium

Forming Female Gametes Chythrid Fungi Flagellated, swimming spores require water for dispersal Ancestral group, gave rise to modern fungi Forming Male Gametes Forming Female Gametes

Zygote Fungi Live in soil and on decaying plant matter Zygosporangia = reproductive structures producing haploid spores

Sac Fungi Ascus = sac that surrounds haploid ascospores

Club Fungi Basidium = club-shaped reproductive structure that produces basidiospores

Fusion forms diploid zygote. Mushroom gills bear reproductive basidia. Club Fungus Life Cycle Haploid Nuclei Fusion forms diploid zygote. Basidia on gills The mushroom (top left) is a reproductive structure formed from aggregated hyphae made up of cells that each contain two haploid nuclei. Within the cap, leaflike gills bear numerous basidia (top right). Within each basidium, the two haploid nuclei fuse, producing a diploid zygote. The zygote then undergoes meiosis, forming haploid basidiospores that are released from the basidia (right). After dispersal by wind or water, the basidiospores germinate, forming haploid hyphae. When hyphae of different mating types meet, some of the cells fuse. These cells, each containing two haploid nuclei, produce an extensive underground mycelium (bottom). Under appropriate conditions, portions of the mycelium aggregate, swell, and differentiate, poking up through the soil as mushrooms and completing the cycle. MEIOSIS Basidiospores (haploid) Haploid 1n Mushroom gills bear reproductive basidia. Diploid 2n

- Club Fungus Life Cycle + Basidiospores (haploid) Basidia on gills Hyphae aggregate to form mushroom The mushroom (top left) is a reproductive structure formed from aggregated hyphae made up of cells that each contain two haploid nuclei. Within the cap, leaflike gills bear numerous basidia (top right). Within each basidium, the two haploid nuclei fuse, producing a diploid zygote. The zygote then undergoes meiosis, forming haploid basidiospores that are released from the basidia (right). After dispersal by wind or water, the basidiospores germinate, forming haploid hyphae. When hyphae of different mating types meet, some of the cells fuse. These cells, each containing two haploid nuclei, produce an extensive underground mycelium (bottom). Under appropriate conditions, portions of the mycelium aggregate, swell, and differentiate, poking up through the soil as mushrooms and completing the cycle. “+” Mating Strain “-” Mating Strain Basidiospores germinate forming hyphae (haploid). + - Haploid 1n Hyphae fuse, but haploid nuclei remain separate in binucleate cells Diploid 2n

Imperfect Fungi Sexual reproduction has not been observed Counterclockwise from top left: Staurospore, Penicillium on apple (Coremia), Sphaeropsis

Applying Your Knowledge Chytrids Zygote Fungi Sac Fungi Club Fungi Imperfect Fungi Which group of fungi Encloses haploid spores within an ascus? Has flagellated gametes? Has an umbrella-shaped reproductive structure called a basidium? Has not shown sexual reproduction?

Applying Your Knowledge Chytrids Zygote Fungi Sac Fungi Club Fungi Imperfect Fungi Which group of fungi Are found on as a topping your mushroom pizza? Caused the pizza dough to rise? Make up the fuzzy structure on the two-week old loaf of bread in your cupboard?

Applying Your Knowledge Prokaryotes Protists Fungi Plantae Animalia Which kingdom/domain Has organisms that are heterotrophic by ingestion? Has cell walls made of chitin? Reproduces by binary fission?