Bio 3218 Lecture 4 -- Fungus Like Organisms and Chytrids (basal Fungi)

What are the 3 Groups of Fungus-like Organisms

1. Kingdom Rhizaria

2. Kingdom Chromista

3. Kingdom Amoebozoa

What Classes Belong in Kingdom Rhizaria

- Plasmodiophoromycetes

What Phylum Belong in Kingdom Chromista

- Hyphochytriomycota

- Labyrinthulomycota

- Oomycota

What Classes Belong in Kingdom Amoebozoa

- Myxomycetes

- Dicytosteliomyctes

Kingdom Amoebozoa, Phylum Mycetozoa, Class Myxomycetes

- Plasmodial slime moulds

- Ex. Stemonitis fusca

What is a Plasmodium

- an acellular mass of protoplasm that glides around

- feeding by engulfing organic particles, bacteria, and other microbes

What is the Difference Between Stemonitales and Comatricha

- In Stemonitales the capillitium ("hair ends") are joined/ connected

- In Comatricha the capillitium ("hair ends") are free

What is the Function of the Capillitium

- Absorbs water

- Flings spores out so they can germinate

What is a Capillitium

- a mass of very fine threads interspersed among the spores of certain fungi

Do Spores Have a Cell Wall

- NO

Do Ameobas Have a Cell Wall

- No cell wall, only a cell membrane

- They will eventually lose 1/2 cell membranes

- Cell membrane has a pool of slime remains

Kingdom Amoebozoa, Phylum Mycetozoa, Class Dictyosteliomycetes

- The cellular slime moulds

- Ex. Dictyostelium discoideum

- Important in biochemical studies of development and intercellular communication via c-AMP

What is a Pseudoplasmodium

- A multicellular mass of protoplasm that glides around

- Feeding by engulfing organic particles, bacteria, and other microbes

Why is Dictyostelium discoideum Used for in Research

- Because of how it interacts with cells using c-AMP

Life Cycle of a Spore

1. Spore

2. Germinating Spore

3. Amoeba

- engulf bacteria and other small particles of food

4. Bacterial colony

- aggregates to form a larger structure

5. Aggregation

- there is genetic variation here

- amoeba aggregates with other amoeba to form this structure

6. Slug

7. Young Sporangium

8. Mature Sporangium

- made up of stalk cells: cells which make up a stalk for other cells to climb up

- were once amoeba that got left behind when fruiting bodies were formed

- group of spore cells form a ball ontop of stalk cells

9. Cycle REPEATS

Kingdom Rhizaria, Phylum Cercozoa, Class Plasmodiophoromycetes

- The plant slimes

- Have an acellular plasmodium within plant tissues

How do Plant Diseases Infect Fungi

- Infect via swimming zoospores (flagellete stage)

- Form a plasmodium and eventually resting spores within the plant tissues

What is the Zygotic Meiosis Life Cycle of Spongospora subterranea

Kingdom Chromista, Phylum Hyphochytriomycota

- Tinsel tailed water moulds

- Contain a single flagellum but it is tinsel flagella

- Asexual

- Small minor group in terms of # of species

- important in regulating numbers of freshwater plankton algae, chytrids, and oomycetes

Kingdom Chromista, Phylum Labyrinthulomycota

- Net slimes

- Have a pseudoplasmodium, but take the form of a net or reticulum

- Marine and have cellulose cell walls

Kingdom Chromista, Phylum Oomycota

- Two-tailed water moulds

- Have a cellulose cell wall and 2 different flagella:

1. Whiplash Flagellum

2. Tinsel Flagellum

- Includes many important plant pathogens

- including Phytophthora infestans --> cause of late nlight of potato

What Happens to Potato Leaves Under Warm/Dry Conditions

- Most of the field will survive

What Happens to Potato Leaves Under Cool/ Moist Conditions

- Most of the field will not survive

What is a Phytopthora

- Goes through the plant, kills it, and digests it for its nutrition

What is the First Part of a Plant to Die

1. Leaves

2. Stem

What Does the Oomycota Have

- cellulose cell wall

- biflagellette zoospores

- this tells us that it is not a unikont

What is a Deciduous Zoosporangium

- another word for spore

- drops and gets blown by wind

- can either land on a leaf in cool/ moist conditions or it lands on a leaf in warm/dry conditions

Cool/Moist Conditions:

- spore hatches and releases zoospores

Warm/ Dry Conditions:

- spore germinates with a hyphae

What is a Necrotrophic Pathogen

- a pathogen that feeds on dead stuff

What do Antheridium Make

- makes sperm nuclei

What do Oogonium Make

- makes eggs

What are Oospheres

- aka. an egg before it turns into an oospore

- gets fertilized by the antheridium

Asexual Life Cycle of Saprolegina

Sexual Life Cycle of Saprolegina

What is Albugo

- white rust of crucifers

- pustules that are white in colour

What is Myzocytiopsis

- an oomycete nematode parasitoid

- zoospores find a nematode and form an infection

- organism digests the nematodes internal organs

What is Phytophthora Sojae

- development of oospores

- plant pathogen

- sweet pea disease

What is NeocallimastixN

- has multiflagellete zoospores

- an exception to the Chytridiomycota group considering the number of flagella

- is able to digest cellulose

What is Batrachochytrium

- a member of the Chytridiomycota group

- interferes with cell membranes and the uptake of nutrients and water

- causes the extinction of many amphibians such as frogs

What is a Blastocladiomycota

- zoospores contain one flagellum

- zoospores swim out of the zoosporangium

- zoospores follow chemical gradients to find a nematode

- once zoospores find a nematode, it sticks, and eventually zoospores will digest the inside of the nematode