MYCO 2.1C Fungus-like organisms

_ are 5 non-taxonomic ranks resulting from primary and secondary endosymbiosis

Eukaryotic supergroups

Enumerate 5 eukaryotic supergroups

ase ao

1. Archaeplastida

2. SAR clade (Straminopiles, Alveolata, Rhizaria)

3. Excavates

4. Amoebozoa

5. Opisthokonta

_ include heterotrophic and phototrophic protists with common ancestor

SAR clade (Straminopiles, Alveolata, Rhizaria)

_ include many forms of amoebae and slime molds, underwent only primary endosymbiosis

Amoebozoa

Primary vs. Secondary endosymbiosis

• Primary (eu + p) = eukaryotic cell engulfing free-living prokaryote that eventually evolves into 2-membraned mitochondria or chloroplast

• Secondary (eu + eu) = eukaryotic cell engulfing eukaryotic cell, eventually evolving into 3-4-membraned complex plastids

_ were foundational events in eukaryotic evolution

Primary, Secondary endosymbiosis

_ is when an aerobic or photosynthetic bacterium was engulfed by archaeal cell, producing Mycota (true fungi) and Amoebozoa (cellular + plasmodial slime molds)

Primary endosymbiosis

2 products of primary endosymbiosis

• Mycota (true fungi)

• Amoebozoa (cellular + plasmodial slime molds)

*Bc they dont have chloroplasts

T/F: The first eukaryotic cells are aerobic

TRUE

Explain primary endosymbiosis

1. Loss of rigid cell wall in anaerobic archaeon facilitated HGTs

2. Phagocytosis and digestion of other prokaryotes (archaeal/bacterial) increased HGTs, speeding up evol processes

3. Membrane increasingly enclosing chromosome of anaerobic archaeon to protect it

4. Aerobic bacterium was taken up to live symbiotically as promitochondrion

5. Development of multiple mitochondria provided energy for evolution of additional membrane systems and much larger cells

6. First eukaryotic cells are aerobic

_ is when photosynthetic eukaryote was engulfed by another eukaryote, producing SAR clade, which includes protists with common ancestor + Phaeophyta (brown algae)

Secondary endosymbiosis

_ are saprotrophic heterotrophs that secrete enzymes to digest food particles from dead organic matter before ingestion

Oomycetes

SAR clade includes _ + _

Heterotrophic and phototrophic protists with common ancestor + Phaeophyta (brown algae); Straminopiles, Alveolata, Rhizaria

_ is a clade of eukaryotes with stiff tripartite external hairs

Stramenopiles

• All members of this clade bear flagella with many short, hair-like extensions from which its name is derived from

• Members are chemoorganotrophic and phototrophic micro- and macroorganisms

Stramenopiles

3 important fungus-like classes under Straminopiles, example species

loh

• Class Labyrinthulomycota

• Class Oomycota

• Class Hyphochytridiomycota

e.g., Cafeteria roenbergensis = stramenopile heterokont (i.e., cell w 2 dissimilar flagella)

_ is the class of stationary filamentous “water molds” and their terrestrial relatives

Oomycetes

T/F: Oomycetes are called “water molds” because they’re mostly found in water

TRUE

Oomycetes are saprotrophic heterotrophs because _

they secrete enzymes to digest food particles from dead organic matter before digestion

T/F: Oomycota can act as plant and animal parasites/pathogens

TRUE

• Oomycota was previously grouped with fungi (Mycota) because _

• Unlike fungi, however, they have cellulose in their cell walls and have a diploid (2n) vegetative state

zfc

• Ability to make zoospores

• Filamentous growth

• Presence of coenocytic hyphae that develops into a mycelium

Oomycota was previously grouped with mycota because of their ability to make zoospores, their filamentous growth, and presence of coenocytic hyphae that can grow into mycelia zfc

Unlike fungi, however, they _

• Have cellulose in cell walls

• Have diploid (2n) vegetative state

Oomycetes reproduce through _

zoospores, oospores

In oomycetes, _ is used as main dispersal mechanism via zoospores capable of chemotaxis in surface waters and water films; some have wind-distributed spores

asexual reproduction

In oomycetes, _ is achieved using oospores, which are double-walled, stress-resistant and form from fusion of oogonium + antheridium (n+n), undergoing plasmogamy to become diploid (2n)

Sexual reproduction

Describe Oomycota life cycle

1. Asexual

   1. Either zoospores (motile, flagellated sexual) from sporangium encyst or conidia (nonmotile, asexual) infects host epidermal cell, causing diseased structures

   2. Inside host, hyphal structures (2n) form sporophore that can differentiate into either sporangium, producing motile zoospores, or asexual nonmotile conidia which can reenter life cycle

2. Sexual

   1. 2n spores germinating into 2n hyphae infect host epidermal cell, causing diseased structures

   2. Inside host, 2n hyphae undergo meiosis, forming 1n oogonium and antheridium, which can then undergo plasmogamy to form (n+n) oospore

   3. Oospore undergoes period of survival, eventually undergoing karyogamy to produce 2n oospore

   4. 2n oospores matures into thallus, which can then release 2n spores, which can then be dispersed and restart life cycle

_ is a class of heterotrophic protists that produce networks of filaments or tubes that function as “tracks” for cellular gliding movement or nutrient absorption

Labyrinthulea

_ are mostly marine and found as parasites of algae and seagrass or as saprotrophs

Labyrinthulea

T/F: One distinguishing feature of Labyrinthulids is that they create membrane-surrounded filaments connect to cytoplasm which encloses thraustochytrids and surrounds labyrinthulids (ectoplasmic nets)

FALSE

One distinguishing feature of Labyrinthulids is that they create membrane-surrounded filaments connected to cytoplasm which encloses Labyrinthulids (ectoplasmic nets) and surrounds Thaustrochytrids

2 main groups under Labyrinthulea

• Labyrinthulomycota (A) = slime nets

• Thraustochytridiomycota (B-C) = saprotrophic decomposers

Both Labyrinthulomycota and Thraustochytridiomycota have _

biflagellated zoospores

_ have several fascinating fruiting body forms

Slime molds

Unique feature of Labyrinthulea

Create membrane-surrounded filaments connected to cytoplasm which enclose Labyrinthulids (ectoplasmic net) and surround thraustochytrids

_ are saprotrophic and parasitic protists that create filaments for movement and feeding

Labyrinthulea

T/F: The predominant life cycle of Labyrinthulomycetes is sexual

FALSE

The predominant life cycle of Labyrinthulomycetes is asexual

T/F: Labyrinthulea have motile zoospores in their life cycle, but asexual reproduction is predominantly utilized

TRUE

T/F: In Labyrinthulea, sexual reproduction is present from gametes derived from sporangia but not well-described

TRUE

Describe Labyrinthulea (Thaustrochytrid) life cycle

1. Vegetative reproduction begins with mononucleated cell that divides to for multinucleated cells, which develops into sporangia that eventually releases its zoospores which can become mononucleated cells again, restarting cycle

2. Mononucleated cells can also enter amoeboid loop by undergoing binary division, forming cell cluster that eventually develops into amoeboid cell and multinucleated amoeboid cell, eventually developing into sporangia > release zoospores > become mononucleated cells > re-enter amoeboid loop

3. Mononucleated cells can also divide to form sporangia containing gametes, which are eventually released. Gametes of opposite mating types fuse, forming 2n zygote

T/F: Thaustrochytrids are well-studied because they produce fatty acids good for human health (DHA)

TRUE

_ is a small group with 6 genera (1/2 dozen), characterized by simple nonmycelial holocarpic thallus (whole cells mature into sporangium)

Hyphochytriomycetes

_ feed on decaying matter and maintain themselves for extended period of time in a vegetative state

Slime molds (amoebozoa)

_ is a group of organisms whose whole cells mature into sporangium

Hyphochytriomycetes

_ is a group composed of organisms that produce cells that develop into sporangia

Hyphochytriomycetes

_ are widespread in occurence, mostly saprotrophs or parasitic, infecting resting spores of Oomycota and Glomeromycota

Hyphochytriomycetes

Describe life cycle of Hyphochytriomycetes

• Normally

  • Zoospore > Cyst > Germling > Mature thallus (but not entire cell becomes thallus)

• Hyphochytrids

  • Zoospore > Cyst > Germling > Whole cell becomes sporangium/thallus

Slime molds are amoebas once thought to be fungi due to _

lsf

• Similar life cycles

• Production of spores and fruiting bodies

_ refers to vegetative structure in slime molds that engulfs materials in its path

Plasmodium

_ are a nonwalled, multinucleate mass of cytoplasm that forms the plasmodium (vegetative structure that engulfs materials on its path)

Plasmodial slime mold

_ has a vegetative structure that is a single amoeboid cell; cells can swarm and form pseudoplasmodium during nutrient depletion and also form sporangia

Cellular slime molds

_ are the only macroscopic slime molds

Plasmodial slime molds (Myxomycota)

Explain Plasmodial Slime Molds (Myxogastria) life cycle

_ can aggregate to form microscopic fruiting bodies

Cellular slime molds

Cellular slime molds can aggregate to form _

microscopic fruiting bodies

Explain life cycle of Dictyostellida

amcm

1. Aggregation of amoeba

2. Migration of slug from aggregated amoeba

3. Culmination of migration and formation of fruiting bodies

4. Mature fruiting body w stalk and head