KINGDOM FUNGI. DNA evidence now indicates kingdom fungi is more closely related to animals than...

KINGDOM FUNGIKINGDOM FUNGI

DNA evidence now indicates kingdom fungi is more closely

related to animals than plants!!!!

The Body of a Fungus• Fungi exist mainly in the

form of slender filaments (hyphae).– long chains of cells

joined end-to-end divided by cross-walls• rarely form complete

barrier• cytoplasm freely

streams in hyphae– mycelium - mass of

connected hyphae

General Characteristics–Fungi are heterotrophs.

(Decomposers)–Fungi have cell walls that include

chitin and not cellulose like plants do.

–Chitin is also found in insects!!!

How Fungi Reproduce• Spores most common means

of reproduction– may form from asexual

(mitosis) or sexual processes (meiosis)

– most often dispersed by wind but some spread by insects or other small animals

– Fungi are grouped by the way they reproduce

How Fungi Obtain Nutrients• All fungi obtain food by

secreting digestive enzymes and then absorbing the organic molecules produced (external digestion).– extensive hyphae

network provides enormous surface area for absorption

– many fungi able to break down cellulose in wood

Ecology of Fungi

• Fungi and bacteria are the principal decomposers in the biosphere.– mineral cycling

• Fungi are virtually the only organisms capable of breaking down lignin.

• Fungi often act as disease-causing organisms for both plants and animals.– agricultural damage– human health

Kingdom Fungi – you must know 4 Major Phyla

1. Phylum Zygomycota = the Bread Molds

Rhizopus – black bread mold

2. Phylum Ascomycota = the Sac Fungi

Yeast, morels, truffles

3. Phylum Basidiomycota = the Club Fungi

Mushrooms, puffballs, bracket fungi, rusts, smuts, toadstools

4. Phylum Deuteromycota = the Fungi Imperfecti

-Regarded as imperfect because they exhibit no sexual stage has been observed in their life cycle

-Members are not closely related and are not necessarily similar in structure or appearance; do not share a common ancestry, polyphyletic = coming from many ancestors – hmm weird

Deuteromycota (Imperfect Fungi)

Deuteromycota – the Fungi Imperfecti

• Resemble Ascomycetes, but their reproductive cycle has never been observed

• Penicillium used to be imperfect but is not anymore!!!

• Different from Ascomycetes because there is a definite lack of sexual reproduction, which is why they are called Imperfect Fungi

Penicillium fungi

Up Close

-are primarily decomposers

-asexual spores may be produced in sporangia

-sexual reproduction occurs between + and – strains forming a 2n zygote; a zygospore develops and may lie dormant for a long period of time; meiosis occurs just before germination

-only the zygote is diploid; all hyphae and asexual spores are haploid

Zygomycota (Rhizopus) the Common Molds

Zygomycota – common molds

The fungal mass of hyphae, known as the MYCELIUM penetrates the bread and produces the fruiting bodies on top of the stalks

Mycelia = a mass of hyphae or filaments

Rhizoids = root-like hyphae

The zhizoids meet underground and mating occurs between hyphae of different molds (SEXUAL REPRODUCTION)

Ascomycota

• Very large group including yeasts, common molds, and morels

• Named for reproductive structure ascus

Ascomycota

• Yeasts– unicellular - most reproduction is asexual and

takes place by cell fission or budding• ferment carbohydrates• play a leading role in genetic research

Basidiomycota

• Most familiar fungi (mushrooms, toadstools, puffballs, rusts, and smuts)– named for characteristic sexual reproductive

structure, basidium

Basidiomycete or Club Fungi

Basidiomycota

Bracket Fungi

Puff Balls

Mushrooms

Jelly Fungi

Basidiomycete Fungi that all produce Basiospores

Other Basidiomycetes Rusts and Smuts

Rust infecting wheat leaves

Rust infecting a Leaf

Whitrot Smut digesting old wood

Lichens• Lichens are symbiotic associations between a

fungus and a photosynthetic partner.– usually ascomycetes

• Specialized fungal hyphae penetrate photosynthetic cells and transfer nutrients to fungal partner.

– Durable fungus, combined with photosynthetic properties, has enabled lichens to invade harsh climates.

– extremely sensitive to pollutants

Crustose

Foliose

Fruticose

Mycorrhizae

• “myco” = fungus and “rhiza” = root• Symbiotic association between plant

roots and fungi• Several different types of association

(defined by structure of fungus:plant interface)

Mycorrhizae

The plant photosynthesizes while the fungus more efficiently takes up nutrients and water from the rhizosphere than the roots would alone.

Plant benefits include:•Improved nutrient/water uptake •Improved root growth •Improved plant growth and yield •Improved disease resistance •Reduced transplant shock •Reduced drought stress