Body Structure • the Morphology of Multicellular Fungi Hyphae

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Body Structure Hyphal Structure • The morphology of multicellular fungi • Most are multicellular – Enhances ability to absorb nutrients – Cells divided by septa – Chitin Reproductive structure. The mushroom produces tiny cells called spores. • Some have no cross Hyphae. The mushroom and its subterranean mycelium are a Figure 31.3 continuous network of hyphae. wall- Coenocytic

Hyphae

Spore-producing structures

20 µm

Hyphal Structure Hyphal Structure

Hyphae Nematode 25 µµµm

haustoria

(a) Hyphae adapted for trapping and killing prey

Figure 31.4a, b Figure 31.4a, b

Mycorrhizae Fungus-Plant Symbiosis • Are mutually beneficial relationships between • Mycorrhizae fungi and plant roots – Increase plant productivity – Mycorrhizae “fungus roots” • Delivers minerals and receives organic nutrients

– Ectomycorrhizal fungi : Grow in extracellular RESULTSRESULTS spaces of roots – Endomycorrhizal fungi : Hyphae go through cell wall to plasmamembrane

Saccharomyces cerevisiae • Brewer's yeast tolerate up to about 5% alcohol. Beyond this alcohol level the yeast cannot continue fermentation. Wine yeast on the other hand tolerates up to about 12% alcohol. The level of alcohol tolerance by yeast varies from 5% to about 21% depending on yeast strain. • Part 1 Aerobic (Oxygen is present) This is the initial rapid process where the yeast is doubling its colony size every 4 hours. (Usually 24-48 hours) • Part 2 Anaerobic. (No oxygen present) Slower activity and the yeast focuses on converting sugar to alcohol rather that increasing the number of yeast cells. (This process can take from days to weeks depending on the yeast and the recipe)

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Diploid phase follows karyogamy • The overall process of fermentation is to convert glucose sugar (C6H12O6) to alcohol (CH3CH2OH) and carbon dioxide gas (CO2). • Short-lived (2n) spore-producing structures and The reactions within the yeast to make this happen are very (1n) spores complex but the overall process is as follows: • C6H12O6 ====> 2(CH3CH2OH) + 2(CO2) Sugar ====> Alcohol + Carbon dioxide gas (Glucose) (Ethyl alcohol) • Note: The sugars used can be a range of fermentable sugars. These sugars are converted by enzymes to glucose which is then convered to alcohol and CO2

Ascocarp

Basidiocarp Sporangia

• Concept 31.3: Fungi descended from an • Concept 31.4: Fungi radiated into a diverse aquatic, single-celled, flagellated protist set of lineages • Fungi and Animalia as sister kingdoms • Fungi early colonizers of land, probably as symbionts with plants.

Chytrids Zygomycetes • Found in freshwater and terrestrial habitats • Fast growing bread and fruit molds • They can be saprobic or parasitic • Can also be parasitic or symbiotic relationship • Zoospores : unique with flagellated spores

Hyphae

Figure 31.10

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Zygomycetes Key Zygomycetes Haploid ( n) Heterokaryotic (n + n) Diploid (2 n) • Pilobolus “aim” their sporangia toward the light

PLASMOGAMY Rhizopus Mating growing type (+) on bread Mating type (–) 100 µm

SEXUAL REPRODUCTION

Dispersal and Zygosporangium germination Sporangia (heterokaryotic) KARYOGAMY

Sporangium Diploid nuclei ASEXUAL REPRODUCTION MEIOSIS Zygospore Dispersal and Figure 31.13 germination Mycelium Figure 31.14 50 µm

Zygomycetes Glomeromycetes • Pilobolus “aim” their sporangia toward the light • arbuscular mycorrhizae • See Figure 31.15

http://www.agro-genesis.com/pics/cropscience_rhizogold1.jpg

Ascomycetes Glomeromycetes • Spores produced in a saclike asci “sac fungi” • Asci are within the ascocarp

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Basidiomycetes Mushrooms are examples of basidiocarps • Include mushrooms and shelf fungi • Clublike structure called a basidium

Figure 31.20

• Concept 31.5: Fungi have a powerful impact on ecosystems and human welfare

Decomposers Fungus-Animal Symbiosis • Essential recycling between the living and • Helping break down plant material nonliving world

Figure 31.22 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lichens Lichens • Symbiotic association of photosynthetic • The fungal component microorganisms held in fungal hyphae – Is most often an Ascomycete Ascocarp of fungus Soredia

Fungal Algal • Algae or cyanobacteria hyphae layer – Occupy an inner layer below the lichen surface

(a) A fruticose (shrub-like) lichen

Algal cell

Fungal hyphae m µ Figure 31.24 10 Figure 31.23a–c (b) A foliose (leaf-like) lichen (c) Crustose (crust-like) lichens

Pathogens Practical Uses of Fungi • About 30% of known fungal species • Make cheeses, alcoholic beverages, and bread – Are parasites, mostly on or in plants • Genetic research on fungi is leading to applications in biotechnology • Antibiotics produced by fungi treat bacterial infections

(a) Corn smut on corn (b) Tar spot fungus on maple leaves (c) Ergots on rye Figure 31.25a–c

Charophytes Overview: The Greening of Earth • 3 billion years terrestrial surface was lifeless

Red algae • Now roughly 290,000 living plant species

ANCESTRAL Viridiplantae Chlorophytes ALGA Streptophyta Charophytes Plantae

Embryophytes