Med bot quiz deux

Question 1

Constitutive vs induced defenses?

Answer 1

“constitutive defenses” are protective mechanisms that are always present, regardless of an attack, while “induced defenses” are only activated in response to a threat like herbivory or pathogen infection

Question 2

Induced responses differ by type of attack, give 2 examples:

Answer 2

chewing herbivores vs. pathogens

Question 3

Herbivore response centers on what?

Answer 3

the jasmonic acid (JA) signaling cascade

Question 4

Pathogen response centers on what?

Answer 4

hypersensitive response, phytoalexins, and salicylic acid (SA) signaling cascade

Question 5

Elicitors are

Answer 5

hybrid herbivore-plant molecules that signal herbivory damage (and can tell plant about identity of specific herbivore)

Question 6

Fatty acid amides = what are, and what do for le plant?

Answer 6

fatty acid from plant + amino acid from insect gut

Initiate downstream defenses in plant

Question 7

In what way is jasmonic acid important? Who does it primarily effect?
(bonus for what type of defense)

Answer 7

JA is an essential signal in both local and systemic herbivory response, primarily through its effect on gene transcription

(herbivory defense)

Question 8

Linolenic acid is what and from what?

Answer 8

a fatty acid derived from membrane lipids

Cyclized in chloroplast, then further hydrolyzed in peroxisome by β-oxidation pathway (which is also involved in hydrolysis of fats)

Question 9

JA mechanism of acion (god bless you brave soldier)

Answer 9

1) JA is conjugated to isoleucine (an amino acid) by JAR1

2) JA-Ile binds to SCF-ubiquitin complex

3) JA-Ile-SCF complex targets JAZ repressor (of other transcription factors) protein, which is then degraded

4) With no JAZ, MYC2 and other transcription factors can initiate transcription of defense genes

Question 10

Biosynthesis enzymes of all major secondary metabolite pathways

Answer 10

1) α-amylase inhibitors:
2) lectins:
3) protease inhibitors
4) JAZ

Question 11

α-amylase inhibitors:

Answer 11

inhibit insect amylases that break down starch

Question 12

protease inhibitors:

Answer 12

block enzymes that break down plant proteins

Question 12

lectins:

Answer 12

proteins that bind to carbohydrates and epithelial cells of the insect’s gut

Question 13

Plants use volatile chemicals in defense- why??

Answer 13

Signal to predators and parasites of herbivores
Also signal to self and neighboring plants to induce jasmonate response

Question 14

JAZ:

Answer 14

interestingly, JA signal initiates JAZ transcription. Remember that JAZ is a repressor protein of JA-induced genes.
What kind of feedback is at play here?

(negative feedback loop to make sure JA doesnt happen too long)

Question 15

Examples of volatile plant chemicals

Answer 15

Various low-molecular-weight compounds (terpenoids, phenolics, and alkaloids, as well as green leaf volatiles = aldehydes, alcohols, and esters)

Question 16

**review slide 12

Answer 16

yeaa know the rough roder/idea

Question 17

What are saponins? What type of defense is this?

Answer 17

pathogen defense molecules, look like honeycomb,

constitutive defense,

binds to sterols on fungal membranes

Question 18

Receptors for pathogen-specific proteins – can also be considered a type of

Answer 18

elicitor

Question 19

MAMP =
What are and what for?

Answer 19

microbe-associated general molecular pattern

Very general receptors that recognize broad groups such as oomycetes or flagellated bacteria

Question 20

R genes

what are and what for?

Answer 20

(R for resistance):

recognize more specific markers from a given pathogen, sometimes even strains within a species

Question 21

Activation of MAMP and R genes receptors initiates what and who is most important in that

Answer 21

signaling cascades: most important seem to be Ca2+, salicylic acid, and production of phytoalexins

Question 22

hypersensitive response-

Answer 22

Ca2+ signals nitric oxide and reactive oxygen species production →

Question 23

The hypersensitive response does what?

Answer 23

This is a kind of a “nuclear option” that kills cells locally, both plant and pathogen

Followed by production of lignin and callose in cell walls of healthy cells = barrier to further infection

Question 24

What are phytoalexins?

Answer 24

Rapidly transcribed locally in response to pathogen attack

Diverse classes of compounds - could be isoflavones, sesquiterpenes, etc.

Strong antimicrobial activity

Question 25

What is salicylic acid good for?

Answer 25

Salicylic acid is an important signal in systemic acquired resistance (SAR) response of plants

Locally initiates transcription of pathogenesis-related (PR) proteins - diverse functions related to defense, including glucanases and chitinases (pathogen-specific polymers)

Question 26

SA is converted into

Answer 26

methyl salicylate (MeSA – in mind also known as the Jar Jar Binks molecule)

for transport through phloem tissues to all parts of the plant = systemic response → upregulation of PR genes throughout plant

MeSA is also volatile, signals to self and other plants

Question 27

See slide 20

Answer 27

slay