lab 9

fungi

• main eukaryotic decomposers on the planet

• parasitic: obtain nutrients from living organsisms

• Saprophytic: obtain nutrients from dead organisms

fungal structure

• Most biomass is in their mass of filaments called mycelia

• Individual mycelia fillaments are called hyphae

• Mycelial morphology allows fungi to grow directly into their food to digest it

hyphae

• this is fundamental fungal units

• filamentous strands of cells that can grow to extreme lengths

• each fungal cell has a cell wall made of polysacharide chitin

• fairy rings

fungal feeding

• Fungi utilize external digestion

• secrete enzymes that break down organic material

• Digest food absorbed into hyphae

• have specialized enzymes that break down lignin

• These fungi are the primary decomposers of dead wood in terrestial environments

fungal reproduction

• reproduce asexually and sexually

• all fungus can reproduce asexually, but they are divided into three groups based on differences in thier modes of sexual reproduction

yeast budding

• yeasts are weird in that they are unicellular fungi

• reproduce asexuallying by budding

• used for brewing beer/ baking bread

fungal groups

• chytridiomycota

• mucoromycetes

• basidiomycota

• ascomycota

mucoromycota

• mainly soil dwelling saprophytes

• Some zygomycetes are parasites to plants, incects, and small animals

• ex: bread and fruit molds

• to sexually reproduce they form diploid zygospores in the zygosporangium that will undergo meiosis, yielding haploid zygomycete spores

basidiomycota

• most familiar fungal group

• mainly saprophytic species

• reproduce sexually via the formation of specialized club-shaped cells called basidium that bear basidiospore

• ex: mushrooms, toadstools, puffballs, shelf fungi, & rusts

ascomycota

• largest fungal group w/ 64K species

• ex: morels, molds, lichens, truffels and single celled yeasts

• the defining feature of this group is the ascocarp which contain the ascus: a microscopic sexual steucture in which ascospores are formed

lichen

• mutualistic symbolic relationship between cynobacteria or green algae and fungus (ascomycota)

• three growth formations:

  1) crutose

  2) foliose

  3) fruticose

mycorrihzal relationships

• some fungi form mutualistic relationship w/ plant roots

• plant receives increased surface area of root system for enhanced uptake of water and nutrients

• fungus receives carbs and sugars from the plant

athletes foot fungus

• ascomycota foot fungus that usually grows between the toes or on the bottoms of the foot

• causes redness, itchiness, & cracking

• diagnosis confirmed through culturing or seeing hyphae under microscope

parasitic fungus

• fungi can also affect living plants

• the tapering deforms fungus infects peach trees causing “leaf curl disease”

• Anthracnose fungi infect sycamore trees

• The fungus must infect inside the epidermal cell of the living plant in order to steal nutrients

killer fungi

• cordyceps is a genus of parasitic ascomycota (sac fungi)

• this is know as the mind controlling fungi & is the last of us fungi

• its mycelium invades and eventually replaces host tissue, with its fruiting body (ascocarp) often sprouting through the host tissue