Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

L3 Plant Sciences > Week 15 L2: Plant-microbe Interactions pt. 2 - PATHOGEN LIFESTYLE > Flashcards

Week 15 L2: Plant-microbe Interactions pt. 2 - PATHOGEN LIFESTYLE Flashcards

1
Q

What did Louis Pasteur and Robert Koch discover?

A

animal diseases were caused by microbes, and the germ theory was born

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Can the Koch’s postulates be applied to plats?

A

YES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are Koch’s postulates?

A

•The microbe is always associated and isolated
from the patient with the disease
•The microbe must be grown in pure culture
•The microbe can be injected or inoculated into an
animal (plant) and cause disease
•The microbe can be re-isolated in pure culture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What research was carried out to focus on the prevention and control of disease outbreask?

A

chemical warfare
Better Hygiene
Genetics of disease resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What family of organisms associate with plants intracellularly?

A

viruses and prokaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What family of organisms associate with the plant extracellularly?

A

prokaryotes and eukaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are examples of eukaryotes?

A 
Fungi
 Oomycetes
 Nematodes
 Insects
 Plants!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Can plants infect plants?

A

YES, parasitic plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are mutualistic symbionts?

A

symbioses that are beneficial to both (or all) symbiotic partners; they are intricate, complex and variable in their

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are examples of mutualistic symbionts?

A

Mycorrhizae (fungi)

Rhizobium (bacteria)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does Mycorrhizae work?

A

ecto or endo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the difference in endo and ecto invasion?

A

endo - fungus invades the plants cells directly

ecto - fungus invades around the plant cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does ecto Mycorrhizae invasion cause?

A

a Hartig net structure.

work intercellularly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does endo Mycorrhizae invasion cause?

A

Arbuscules, finger-like protrusions inside the cell. maintained within cellular membrane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are Rhizobium responsible for?

A

Nitrogen fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do many bacteria attach to the plant?

A

by producing biofilms to stick to plant tissue.

Xylella fastidiosa in a xylem vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do some pathogens use to stick to the plant?

A

polysaccharides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are a few ways in which pathogens are able to penetrate or circumvent physical barriers?

A
  • Melanized appressoria build up high pressure to
    puncture the cell wall
  • Some pathogens enter through stomata and grow
    extracellularly
  • Some pathogens produce non-melanized but effective
    appressoria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the pathogen lifestyles?

A

Biotrophic
Necrotrophic
Hemi-biotrophic

facultative
obligate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is Biotrophic?

A

– feed on living plant tissue, not causing cell death

example=Hyaloperonospora arabidopsidis (oomycete)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is Necrotrophic?

A

kill plant cells and then feed

example=Botrytis cinerea (fungus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Hemibiotrophic?

A

initially biotrophic and then become necrotrophic

example=Pseudomonas syringae (bacteria)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does obligate mean?

A

can only grow on their specific living host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does facultative mean?

A

pathogens can attack living plant cells but can also

grow by themselves, e.g. on artificial medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is an example of obligate growth?

A

Hyaloperonospora arabidopsidis

26
Q

What are features of biotrophic pathogen?

A 
•“Pretend harmony”
•Fewer cell wall-degrading enzymes 
than non-biotrophs
•Evade detection and avoid 
elicitation of defence responses

Lots of effector cell released

27
Q

What does ‘pretend harmony’ mean?

A

Looks like there’s not a lot of damage taking place but there is.
Lots of effector cells produced to suppress immune response

28
Q

What are features of the necrotrophs?

A
  • “Smash and grab”

* Produce toxins and cell wall-degrading enzymes

29
Q

What does ‘smash and grab’ of necrotrophs mean?

A

Cause cell death and cause a lot of damage.

30
Q

What is haustoria?

A

feeding structures

31
Q

What lifestyle of pathogen makes haustoria?

A

fungal and oomycete hemi-biotrophs

specialized for nutrient and signal exchange

32
Q

What is the role of hyphae?

A

parasitic fungi are specialized for nutrient absorption within a specific host.

33
Q

What is the link between haustoria and Hyphae?

A

The hyphae is the branch which absorbs nutrients and the haustoria penetrate cells and release effector cells.

34
Q

Does the haustoria penetrate the plant cells membrane?

A

no, there is space between the haustorium and the plant cell plasma membrane

35
Q

What is the hemibiotroph’s lifestyle?

A

e.g. phytophthora infestans

invade with appressoria and intracellular haustoria,=.

The infection also causes necrosis of plant tissues.

The plant releases sporangia which develops to a sporangium and eventually a appressorium where the cycle starts again

36
Q

What phase does the haustoria maintain?

A

biotrophic phase

immune suppression

37
Q

What are the sporangia?

A

reproductive organs which can start new cycle of infection.

38
Q

What effectors are the effectors secreted in biotophy vs necrotrophy?

A

bio - immune suppressors effectors

nec - cell death promoting effectors (necrosis-inducing)

39
Q

What do necrotrophic pathogens thrive on?

A

cell-death environment

40
Q

Why are there not many resistance proteins associated with the nectrophs?

A

as they thrive in a cell-death environment

41
Q

What does DAMPS stand for?

A

Damage-Associated Molecular Patterns (DAMPs).

42
Q

What is DAMPS?

A

When the necrotroph produce cell wall degrading enzymes, the damaged cell wall cells have DAMPS which can be detected by the plant and initiate an immune response. Detect their own damage

43
Q

What are the 2 types of necrotrophs?

A

Broad-sense range

Host-specific

44
Q

Host-specific nectrotrophs produce toxins, what can these be classed as?

A

effectors

45
Q

How can plants become resistant to toxins by host-specific necrotrophs

A
  • mutating the target, not sensitive to toxin

- Desensitisation mechanism - e.g. enzyme which targets toxin and breaks it down.

46
Q

What is Host-specific necrotrophs?

A 
produce specific toxins 
necessary for their 
pathogenicity; sometimes 
these act through specific R 
genes, in a counterintuitive 
manner
47
Q

What is broad-sense range necrotrophs?

A

produce cell wall degrading
enzymes (CWDE), necrosis and ethylene-inducing proteins (NEPs), and also can suppress the plant’s
immune response.

48
Q

Are resistance genes useful with regards to necrotrophic pathogens?

A

No - binding to R protein, makes the plant susceptible due to recognition by the R protein

49
Q

How do biotrophs and necrotrophs differ in hormone response?

A

JA works to defend against necrotrophs

SA works against biotrophs

50
Q

Do viruses also have effectors?

A

YES

51
Q

What mediates plants response to a virus?

A

siRNAs

52
Q

What is siRNA?

A

small interfering RNA

53
Q

How do plants respond to a viruses?

A

Viral components can trigger immune responses through PRRs as well as R proteins, leading to cell death and systemic immunity

54
Q

What are nematodes?

A

Nematodes are tiny
round worms (0.1 mm
diameter) that are
found ubiquitously

55
Q

Where in a plant do nematodes target?

A

roots

stunted roots

56
Q

What are the 2 classes of nematode?

A

root-knot nematode and cyst nematode

57
Q

What happens in the root-knot nematodes?

A

female feeds on plant and induces formation of giant cells, actively changing what plant cells look like in the roots

58
Q

What happens in the Cyst nematode?

A

partially dissolve cells walls between cells to produce a syncytium

59
Q

How do nematodes generally work?

A

nematode effectors modify root cells to become specialised feeding grounds.

Active manipulation by release of effector cells.

60
Q

What do biotrophs do to keep the plant alive so it can keep feeding?

A

biotrophic interaction, it still reduces crop yield but keeps it alive so it can feed

61
Q

What are types of herbivore insects?

A 
– Chewers
– Sap-sucking
– Gall-inducing
– Boring and Mining
– Seed predation

e.g. aphids

L3 Plant Sciences (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions