Exam 1 Flashcards
Ergot and it’s causal agent
A fungus that involves and replaces grain with fungal tissue, usually rye and wheat. Causal agent is Claviceps purpurea
Koch’s postulates
taught us how to prove an organism is responsible for symptoms.
- The suspect must be consistently associated with disease
- The suspect must be isolated in pure culture and characteristically well described
- A clean, healthy plant, must get the disease after being exposed to the suspect
- The usual suspect needs to be re-isolated from the disease plant from step #3
Works extremely well with fungi and bacteria. Harder with viruses. Even harder with nematodes
Late blight and it’s causal agent
Phytophthora infestans, an oomycete is it’s causal agent. Can only be transmitted by spores
The discovery of Bordeaux mixture
Pierre Millardet uses copper solution to PREVENT infections of grape leaves with downey mildew of grapes
Pasteur and germ theory, spontaneous generation
proves concept of germ theory while working with beer and wine, spontaneous generation does not happen
parasite
An organism that withdraws nutrients from another living host
pathogen
An agent that causes disease
hyphae and mycelium
Single, tubular filament of a fungal thallus or mycelium; basic structural unit of a fungus
spores
are like seeds and are carried by the wind to new places where they germinate and form new colonies
conidia
Spores made asexually
obligate parasite
Also known as a biotroph, must have a living host to complete its life cycle
saprobe or saprophyte
An organism that lives off of dead or decaying organic material
disease triangle
All three components are necessary to cause disease
* A susceptible host
* A pathogen
* Environment favorable for disease
disease pyramid
same as disease triangle but the addition of time
to breed true
the offspring are 99.999% genetically identical to parents
virulence
Determined by genetics of the pathogen and the response of the host
polycyclic
There are multiple cycles of infection
monocyclic
There is only one infection event for the growing season
septation
a division between cavities or parts of an organism by partitions or septa
ascospores and ascus
A sexually produced fungal spore formed within an ascus of ascomycetes
basidiospores and basidia
reproductive spores produced by Basidiomycete fungi
haploid state of most fungi
Most fungi are haploid 99% of their lives
homothallic and heterothallic
No male or female, a second organism not always required (mitosis)
antheridium
The equivalent of a male sex organ in ascomycetes. It is”male” because it provides DNA through a nucleus but does not contribute to the “gestation”? of the spore
ascogonium
The “female” piece of ascomycete sex. It becomes larger and is usually where the cells with spores originate from
apothecium
A cup-shaped fruiting body, large or tiny, usually open on top
clamp connection
allows nuclei to move around the septum
plasmogamy
Fusion of two haploid cells
karyogamy
Fusion of haploid nuclei
meiosis
a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores
mycorrhizae
Attaches to plant, feeds the plant water and phosphorous, receives sugar in return
heart rot
a fungal disease that causes the decay of wood at the center of the trunk and branches
alternate host
the host belonging to a different family that helps complete the pathogen’s life cycle and its survival
Wheat rust and its causal agent
a fungal disease that affects wheat, it’s causal agent is Puccinia graminis
alternate host of wheat rust
Common barberry
White pine blister rust and it’s causal agent
Extremely virulent, it’s causal agent is Cronartium ribicola
Corn smut and it’s causal agent
fungi from corn, it’s causal agent is Ustilago maydis
coenocytic mycelium
a mycelium where the hyphae lack septa
zygospore
sexual resting structures
Chytrids
Mostly decomposers in lakes and ponds, major amphibian parasite, obligate parasites in plants
zoospores
Flagellated spore found in chytrids
Potato wart and it’s scientific name
Synchytrium endobioticum, a chytrid fungus that causes the disease, or black scab
4 parameters of disease, signs and symptoms
Process
Physiological
Injurious
Continuous
why and how we classify fungi into different phyla and lower groups
Placement into a division is based on the way in which the fungus reproduces sexually.
why the Deuteromycetes are a dysfunctional group and problematic for taxonomy
these fungi apparently lack sexual stage
the difference between homothallism and heterothallism and put some consideration into what their advantages might be
Heterothallic fungi require two compatible partners for mating to occur and have greater degree of outbreeding that results, whereas homothallic fungi are self fertile with a single individual capable of sexual reproduction even in solo culture
general process of fungal sexual reproduction and the order in which it occurs in fungi
The diploid chromosomes are pulled apart into two daughter cells, each containing a single set of chromosomes. plasmogamy, karyogamy, and meiosis is the order
What is the advantage to conidia?
germinate and create a newer generation and have a very important role to play in biological dispersal
What is the advantage to zoospores?
function in dispersal and allow the fungus to locate new sources of nutrients
wheat rust life cycle order in general terms
Spermatogonia, Aecidium, Uredium, Telium, Basidium
spores, when they happen and the term to describe a rust with this many spore stages
a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavorable conditions (haploid rust)
