Plant Biotechnology Lectures 4-6

Front 1

Blocks plasmodesmata during infection

Back 1

Callose

Front 2

Projection from fungus hyphae that penetrates cytoplasm

Back 2

Haustorium

Front 3

3 enzymes fungi use to break down plant cell walls

Back 3

Cutinase, pectinase, cellulase

Front 4

4 physical defences against plant pathogens

Back 4

Cuticle, lignin, callose and silicon

Front 5

Parasite that depends on living tissue

Back 5

Biotrophs

Front 6

Parasite that depends on dead tissue

Back 6

Necrotrophs

Front 7

Depends on living tissue, then dead tissue

Back 7

Hemibiotrophs

Front 8

Chemical makes fungus/bacteria membrane leaky and is toxic to insects and is an antifeedant

Back 8

Saponins

Front 9

After wounding by herbivores, are activated into toxic mustard oils

Back 9

Glucosinolates

Front 10

Antipathogen, Inserts into plasma membrane, four make a pore. Broad spectrum.

Back 10

Defensin

Front 11

Maize targeted toxin, inhibits histone deacetylases and nucleosome unwinding.

Back 11

Maize HC toxin

Front 12

inactivates HC toxin

Back 12

HC toxin reductase

Front 13

Three types of inducible defense

Back 13

PAMP triggered immunity.

Effector triggered immunity.

DAMP triggered immunity.

Front 14

Generic immune response, initiated externally by pattern recognition receptors.

Back 14

PAMP (pathogen associated molecular patterns) triggered immunity.

Front 15

Pattern recognition receptors respond to...

Back 15

Chitin, flagellin, lipopolysaccharides, ds RNA, cell wall and cuticle fragments.

Front 16

Internal initiation of immunity, specific

Back 16

Effector triggered immunity

Front 17

Triggers for effector triggered immunity

Back 17

Proteases, glycolipids

Front 18

Triggers for DAMPs

Back 18

Cellulose, salicylic acid, bits of cell wall

Front 19

Rapid death of cells in region of infection

Back 19

Hypersensitive response

Front 20

Phase 1 of hypersensitive response

Back 20

Activation of R genes triggers action potential of k efflux and ca/h influx

Front 21

Phase 2 of hypersensitive response

Back 21

Oxidative burst (ROS) break down membrane, trigger deposition of lignin and callose. Systemic: inhibitors of enzymes and chitinases, phytoalexins.

Front 22

Phase 3 of hypersensitive response

Back 22

Intracellular signalling to nucleus, transcribe defense proteins (structural or anti fungal). Cell death, endonucleases, proteases.

Front 23

Inactivator of Salicylic acid

Back 23

Salicylate hydroxylase

Front 24

Stable analogue of Salicylic acid

Back 24

BTH

Front 25

Salicylic acid receptor

Back 25

NPR1

Front 26

PAMP triggered immunity responses

Back 26

Oxidative burst/ROS wave, callose deposition, make salicylic acid and ethylene

Front 27

Incompatible interaction

Back 27

Elicitor recognised by r protein

Front 28

R proteins recognise...

Back 28

Avirulence (avr) proteins

Front 29

Elicitor of systemic acquired resistance

Back 29

methyl salicylic acid

Front 30

Programmed cell death vs...

Back 30

Systemic acquired resistance

Front 31

Function of NPR1

Back 31

DNA binding, enhances transcription of pathogen response genes (chitinases, toxic volatiles, antimicrobials). Directs cell down systemic acquired resistance pathway.

Front 32

NPR4 binds salicylic acid stronger or weaker than NPR3

Back 32

Weaker

Front 33

Role of NPR3

Back 33

Mediates degradation of NPR1 when bound to salicylic acid, encourages cell death

Front 34

Role of NPR4

Back 34

When bound to salicylic acid, it doesn't break down NPR1, favours genes associated with systemic resistance

Front 35

Make systemic acquired resistance more rapid?

Back 35

Overexpress NPR1

Front 36

How to transfer induced pathogen response between species?

Back 36

Clone pattern recognition receptor between species. Eg from model to tobacco

Front 37

Defensin overexpression example

Back 37

Protect potato against fungus but yield penalty

Front 38

How to combat nematode with biotechnology

Back 38

Express ds RNA for peptide that induces giant feeding cells

Front 39

Plant response to salinity

Back 39

Reduced transpiration, accumulation of inorganics in vacuole and osmoprotectants in cytoplasm

Front 40

Three ways to identify genes associated with abiotic stress resistance

Back 40

Quantitative trait loci, genome wide association studies, mutation screen and yeast complementation studies

Front 41

Three general targets for drought, salt or temperature tolerance

Back 41

Osmoprotectants, ion transporters/channels, transcriptional activators of stress tolerance genes

Front 42

Two examples of drought tolerance

Back 42

Rice: deeper rooting 1 (DRO1) increases gravitropism.

Maize: Overexpression of trehalose-6-phosphate synthase improves yield in all moisture conditions. Is osmoprotectant.

Front 43

Four salinity tolerance strategies

Back 43

Overexpress vacuolar Na/H antiporter AtNHX1 in oil seed rape and tomatoes. 200mM NaCl.

Overexpress AVP1 H pump. More protons in vacuole.

Overexpress SOS1 Na/H antiporter (less Na in cell)

HKT1 transports Na out of xylem to parenchyma cell. Tissue specific overexpression in root stele.

Front 44

Four cold tolerance strategies

Back 44

Abscisic acid treatment

Upregulate COR genes

Proline accumulation (osmoprotectant)

Eskimo1 mutant

Front 45

COLD1 SNP effect

Back 45

Makes japonica rice more cold tolerant than indica rice

Front 46

Effect of CBF3 overexpression on yield

Back 46

Lower yield if constitutive, if inducible higher drought, salt and freezing tolerance

Front 47

Aluminium resistance strategies

Back 47

Excretion of organic acids (malate, citrate)

Raise pH of rhizosphere

Front 48

Transporter that confers high Aluminium resistance

Back 48

Malate transporter

Front 49

Polyploidy

Back 49

Plants with more than two paired homologous sets of chromosomes.

Front 50

Homeologues

Back 50

Orthologous genes in the same species due to recent polyploidy.

Front 51

Orthologues

Back 51

Genes originating from a single ancestral gene in last common ancestor of compared genomes.

Front 52

Polyploid species example

Back 52

Brassica napus, oilseed rape

Front 53

Genome of Brassica napus

Back 53

AACC

Front 54

Ancestors of Brassica napus

Back 54

Brassica rapa and Brassica oleracea

Front 55

Brassica rapa genome

Back 55

AA

Front 56

Brassica oleracea genome

Back 56

CC

Front 57

Three factors that make sequencing plant genomes more challenging

Back 57

Polyploidy, highly repetitive regions, many genes/large genome

Front 58

Challenge facing detection of allelic sequence variation

Back 58

SNPs between homeologues can be mistaken for allelic variants.

Front 59

How to detect and score allelic sequence variation

Back 59

High sequence redundancy, sequence-based SNP calling against reference sequence

Front 60

Two requirements for development of genomics platforms for plants without high quality genome sequences

Back 60

Genome sequencing and genetic linkage map

Front 61

How to make genome sequence for making genomics platform

Back 61

Assemble short read contigs with longer reads and assemble genome sequence scaffolds

Front 62

Statistical analysis of coinheritance of alleles is...

Back 62

Genetic linkage map of ordered markers. Hypothetically ordered genes

Front 63

Density and resolution of linkage map dependent on...

Back 63

Scaffold size

Front 64

If large scaffolds not available for SNP calling then use...

Back 64

Scaffolds from related species, contiguous genome better