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Agricultural Biotechology
Experiments to:
1
...

b
...


Screening: assessment of practice
Safety: FDA requirements, must do animal testing which includes dermal, dietary
and inhalation testing
...

Molecular characterisation: assessment of the molecular structure of the
newly created proteins, their functioning and their potential interactions
...

Comparative analysis: comparison of the GM plant with its conventional
counterpart
...
The analysis also compares the
nutritional value of the GM plant and its conventional counterpart
...

Evaluation of potential toxicity and allergenicity
iv
...

v
...


2
...

insect resistant crops

...
dietary exposure of Cry toxins
a
...
, 2000),
and an average human body weight of 70 kg, it would require consumption of 350 kg of maize per day to
attain the dosage of 5 mg of Cry protein /kg body weight
2
...

Allergy: Starlink corn recalled in 2000 because inserted gene with B
...
BUT! Bt reducing insects like the corn borer that damage plants
and allow growth of fungal infections which produce mycotoxins
...
High exposure to toxin
causes liver cancers (Kenya 2004-contaminated maize caused 125
deaths
...

Randall 2016
4
...
to environment
1
...
PLPBR (pests (different ones), loss of food, poisoned larvae,
biodiversity, resistance)
3
...
zea than non-Bt maize sprayed
with insecticides
...

herbicide resistant crops

...
TAN

...
to environment

1
...


PEBRS (genetic pollution, biodiversity, escape genes, resistance to
antibiotics, superweeds)

...
glyphosate is strongly adsorbed to the soil there is a negligible
threat of residual effects on succeeding rotational crops
...
Less contaminated crop for farmers
4
...

payne and Oliver 2000: use normal post
emergence herbicides to kill off resistant ones
ii
...
dominant market for top agro companies as link their seed
production to their chemicals
...

2
...
More expensive seeds but should get return on non contaminated
crop
4
...
to human health
i
...
Establish whether GM is better for environment and biodiversity
...

Efficiency and benefits of GM: how well they work in controlling:

...
virus
ii
...
insect
iv
...
Conventional plant breeding okay is good because lower seed cost
and no import restriction but the seed cost is outweighed because
of potential yield loss due to no resistance and import
restrictions? Well cant get any through if it has fungal damage
...

Agronomic benefits: Brookes 2014: 1996–2012 saw an increase of more than 370 million tons of food
crops
...
S
...

Economic benefits: Brookes 2014: From 2006 to 2012, the global increase in farm income from GM
food had reached $116 billion
4
...

ecosystem services and endangered species
a
...

Does it have any adverse effects on organisms that are not meant to be affected by the GMO
the so-called non-target organisms
d
...
main food produced in the UK: wheat (74%) (the most widely grown arable crop in the UK), barley, oats,
potatoes, sugar beet, vegetables
ii
...

b
...

d
...
Human influence on agriculture

Mechanisation
Seed storage
Human selection
Followed nomadic herds and began planting trees for sedentary animals like pigs

2
...

Improved varieties
a
...
law of diminishing returns
b
...

Deforestation
d
...
All have effect on biodiversity and climate change because of energy used to produce fertiliser in Haber bosch
process etc
e
...
GM crops


...
Good for dicots, can also now use on monocots
i
...
Large fragments
iii
...
can also use A
...

Biolistics

...
Expensive
ii
...
DNA rearrangements/silencing
1
...
high risk of gene rearrangement
b
...
CRISPR: button mushroom to remove polyphenol oxidase by PEG mediated transformation
c
...

Silicon whiskers
e
...

microinjection
g
...
Process of Genetically Modifying Crops


...

Source of genes

...
Labelling and consumer choice?
ii
...

identify trait of interest and isolate it

...
Monsanto: seed chipping
ii
...

Cloning gene of interest into construct

...

Select transformant/marker gene

...
Insert the nptII (neomycin phosphotransferase gene) into the plant
...
But kanamycin controversial because important antibiotic and think cant remain in plant
...
must be expressed in transformed cells and not in untransformed

ii
...
using reporter genes instead: GFP or removing the resistance gene using CRISPR
e
...
Native – from same species
...
Foreign – from another plant
ii
...
Synthetic – tailor made for the purpose?
f
...
On all the time? / constitutive
i
...
Exogenous control/ inducible
1
...
Used in dicots
...

Wu, 2014: Target conserved region of CaMV 35S during PCR for better detection of GM
2
...
E8: fruit specific
4
...
PEP: phosphoenolpyruvate carboxylase tissue specific, only in cells involved
in photosynthesis so shoot, leaves, stem
g
...

Vector

...
Plasmid vectors
1
...

commonly used 800kbp long and removed tumour inducing genes and replace with gene of interest
and reporter genes
2
...

TDNA functions independent of Ti plasmid
...
tumefaciens and E
...
Viral vectors
1
...
TMV

...

Method of transformation

...

Genome editing

...
Rapid Trait Development System (RTDS)
1
...
Done making
plant resistant to herbicide but not through agrobacterium or biolistic
delivery but looked at gene that makes protein herbicide binds to, knew
how needed to be changed so herbicide wont bind
...

ii
...
TALENS
k
...
Reporter Genes like GFP/ antibiotic resistance: grow cells on the right media like Kanamycin or herbicide
i
...
Fluorescing GFP reporter gene: observed under microscope and quantification possible with a spectrometer
iii
...

Licensing Process of GMO’s

...
Level 1: local committee permission and registration of workers
2
...
Level 3: DEFRA permission for modified crops

4
...

ALso need ACRE for field release

...

Not pose a threat to human or environment health
...
Needs registration if contains viable genetic material like roundup ready soybean because contains trypsin
inhibitors, but flour from this doesn’t need licensing
...
look at deliberate change in introduction of genes
2
...

See digestion in gastric juice of new protein and toxicity tests
3
...
Check marker behaves as single dominant locus or expected
5
...
Will some gene editing circumvent the rules
1
...

RNA spray onto plant and plant produce RNA molecule to target pest
...
So easiest approval route or should do longer route to show to anti-GM groups that
it is fine
iii
...
Zhang 2012: plant miRNA regulates gene expression in mammals: cross
kingdom regulation by microRNA so GM implications
iv
...
Outdoor trials take years as effect may be seen later in different soil and
weather types
2
...
Also what crop should it be, if GMO is pollinated by honeybee does barrier
crop need to be flowering too
4
...

The safety assessment of GM foods generally focuses on: WHO 2014

...
(b) potential to provoke allergic reaction (allergenicity)
ii
...
(d) the stability of the inserted gene
iv
...
(f) any unintended effects which could result from the gene insertion
...
Main health concerns for human health

...

As a matter of principle, the transfer of genes from commonly allergenic organisms to non-allergic
organisms is discouraged unless it can be demonstrated that the protein product of the transferred gene is
not allergenic
...
No allergic effects have been found relative to GM
foods currently on the market
...

Gene transfer
c
...
This would be
particularly relevant if antibiotic resistance genes, used as markers when creating GMOs, were to be
transferred
...

d
...

The migration of genes from GM plants into conventional crops or related species in the wild
(referred to as “outcrossing”), as well as the mixing of crops derived from conventional seeds with GM
crops, may have an indirect effect on food safety and food security
...
Several countries have adopted strategies to reduce mixing, including a clear
separation of the fields within which GM crops and conventional crops are grown
2
...

the capability of the GMO to escape and potentially introduce the engineered genes into wild
populations
a
...

the susceptibility of non-target organisms (e
...
insects which are not pests) to the gene product
c
...

the reduction in the spectrum of other plants including loss of biodiversity
e
...


5
...
WBPC
a
...
Pre emergent herbicides
i
...

Benefits

...
reduce inputs?
1
...
Increased yield by 4
...
easier control
iii
...
reduction in foreign matter 0
...
85%
2
...
PRICS
c
...
Glyphosate inhibits EPSPS needed for amino acid synthesis
...

1
...
Monsanto's patented genes being inserted into roughly 95 percent of all
soybeans and 80 percent of all corn grown in the U
...
EPSPS gene from Agrobacterium sp
...

ii
...
As gene wouldn’t have got there naturally
...
Plant makes the agrobacterium protein, protein isn’t inhibited so when spray glyphosate the plants EPSPS
gene is inhibited the other one isn’t so it grows
...
Native plant enzyme is inhibited by glyphosate but transgene product isn’t, so plant survives
v
...
BBC news 2009: monsanto lied about roundup being biodegradable and
benign
2
...
Good as all bacteria/fungi have genes to make amino acids so present in many organisms
1
...
BBC news
...

Roundup Ready soybean

...

i
...
Back crossing segregated inserts giving strain containing CP4-EPSPS
e
...
Ward 2013
i
...

ii
...
Only selected for one gene so can change herbicide
iv
...

Roundup ready sugar beet

...
Extensively processed so safe
ii
...
BUT DUE TO WILD RELATIVES COULD GET GENE ESCAPE?
iv
...

Liberty Link

...
phosphinothricin/PPT/BASTA important to amino acid biosynthesis, inhibits glutamine synthesis essential in
nitrogen assimilation
ii
...
produces enzyme that acetylates PPT (PAT)
...
With 35S promoter confers BASTA resistance
3
...

Syngenta: tavium plus VaporGrip technology manages broadleaf and grass weeds in roundup ready
2Xtend soybeans (resistant to gluphosate and dicamba) and Bollgard II cotton

...
used both pre and post emergence system
ii
...
introduce a degradation mechanism
iii
...
Blocks electron flow in dicots
...

2
...

i
...
Sulphonyl urea: inhibits Acetolactate synthetase (ALS) from isoleucine and valine synthetic pathway
i
...

HR changing farming practices

...
Weeds less tolerant? Change herbicide when resistant
ii
...
Could be used to reduce inoculum pressure
1
...
Grow sacrificial crop to
cause germination of spores but arent hosts to replicate
...
Fewer weeds: what is effect on biodiversity? Insects feed on weeds: monarch butterfly and milkweed example
1
...
Thistles are main part of goldfinch diet
3
...
Hicks 2016: British weed species like dandelions provide more nectar and
pollen than seed mixes for biodiversity
k
...
Risks to consumer
1
...
Toxins/allergens: roundup soybean extensive processing so not toxic

...
Altered nutrition: must go through licensing
i
...
Genetic pollution: insert into junk DNA but does it exist
2
...
Escape of genes
4
...
Antibiotic resistance
ii
...
superweeds and antibiotic resistance

l
...
Crop rotations: Palmer amaranth example
i
...
Field margins
1
...
Stacking of resistance genes? NO! move together
iv
...
Pricing of seed
m
...
Non GM methods
i
...
weed resistance problem?
ii
...
No legislation to regulate use and not blocked by supermarket
1
...
GM for Pest and Disease Resistance


...
Soybean (75%), maize (92%), cotton (30%)
...
Opposition in the EU and considering for human consumption is cause of lack of commercialisation
...
HR crops are 65%, IR crops 35% global plantings
...
Pesticides are: expensive
2
...
Environmental effects:

...

fuel to produce- CO2 production
4
...

Diversity of non target arthropods increased in IR systems
a
...
BT Toxin
1
...
insect ingest spore and protein activated by proteases
...
Used on organic farms! Only affects insect that eats the crop, whereas
spraying with pesticide affects all, can choose right toxin for pest
4
...

European corn borer endemic in USA
a
...

i
...

YieldGard

...

Agrisure Duracade

...
coleoptera and lepidoptera pests
5
...

Cotton bollworm, Pink Bollworm, Tobacco Budworm
a
...

Bollgard

...

Bollgard III Roundup Ready flex

...
VIP3A insecticidal protein: stacked traits
ii
...
BT Potato


...
Not grown commercially
7
...
Romeis 2019: BT crops grown on 100 milion hectares in 2017
...

Could affect non target organisms by toxicity and changes due to IPM
i
...
Inhibit activity of insect gut proteases so cant digest food: move or starve
2
...
Trypsin inhibitor

...
Used for multiple resistance in cotton
4
...

PinII from Solanum tuberosum
...
Little effect against non targets and if too specific can stack them
6
...

overcome by using more than one type of control

...
Bt needs activation so not used with certain PIs
ii
...
Wound induced promoters/tissue specific
1
...

2
...
Not exposed as much so less selection
ii
...
carbohydrate binding proteins: plant defence against pests, found in
storage organs and seeds
...
active against many types of pest
...
But degraded by cooking
...
Allergic reactions? Would need clear labelling and big risk assessment
4
...

1998 Pusztai paper: Snowdrop lectin: Lectin A is GNA
...

Claimed worrying effects
a
...

iv
...
Lectins/PIs/Anti-amylase inhibitors act as them
...
Can add fear pheromones
...
Pulling: add chemicals so reduce area needing spraying
4
...

d
...

chitinase and glucanase degrade cell wall: kill fungus
...
Bean chitinase expressed in tobacco: resistance to Rhizoctonia solani
2
...
Rice Chitinase + alfalfa B-3, 3 glucanase in tobacco: protection against
Cercospora nicotianae than either alone
v
...
not as developed as HR and IR: must understand crop and pathogens
2
...
Resistant genes from other species:
a
...

with existing genes only work where same species/pathogen class infects several species of plant
c
...
modify LRR region to recognise new elicitors: new resistance genes
e
...
insects mutate and become BT resistant: selection pressure
1
...

resistance recessive so keep wild insects around so mate with something susceptible
...

a
...

Depends on how far pollen and pests move

...
g
...
So dont spray with insecticide in IPM
2
...

Unlikely evolve dual resistance
a
...

Fall armyworm: resistance to BT toxin Cry1Fa: resistant in brazil and Puerto Rico
i
...

Monarch butterfly larvae: could GM maize kill it because it doesnt even eat maize
...

Losey 1999: Larvae eat milkweed leaves with BT pollen smaller than controls

...
Used very high levels of pollen on leaves
ii
...
Risks to environment
1
...
Loss of food for other animals when insects die
3
...
Loss of biodiversity: where will new genes come from
5
...
Resistance
7
...

When GM isnt GM

...
silencing move from rootstock to scion: alter traits without being GM
i
...
modify viral genome to include ORF add plant promoter and infect
2
...

Also viruses are unlikely to persist where the vector and host are absent
but viruses can adapt dont forget
3
...

induce host gene silencing pathways
...

RNAi exploit cell machinery used in regulation of gene expression and virus defence, where dsRNA
recognised and cleaved by dicers
b
...
HIGS
1
...
Express in host to silence
essential pest genes

...

Expression CYP51 dsRNA from fusarium gave resistance in barley and arabidopsis
b
...

FgCPY51B and A responsible for sterol demethylation: needed for ascospore formation
d
...

Express dsRNA in arabidopsis which targets all 3 genes, give complete resistance to Fusarium

...
RNA pesticides
1
...
spray onto plant and eaten by larvae
to trigger gene silencing
2
...
Not tubulin/actin or things
that can have same specificity across families

...
graminis secrete effectors into plant cells to prevent host defences and promote
pathogenicity
...
Expression of this
gene in plants promoted susceptibility to many pathogens
iv
...
co-transformation then cross to segregate/remove by directed
recombination
v
...
mutate host genes to become selectable markers: use only host derived
promoters and terminators
...

Genome Modification

...
RNA guided nuclease: Cas9 and gRNA to induce DNA ds breaks
...
Example wheat: genome editing for mildew resistance

...
Delete all 6 alleles to get
resistance
3
...

c
...
Global losses: 22% due to bacterial pathogens, 8% viruses, 18% insect pests
...
Sawai 2014: reduction in steroidal glycoalkaloids (SGAs) SSR2 is key enzyme in cholesterol synthesis
1
...
SSR2 excised by genome editing: impaired cholesterol production and
reduce SGA
ii
...
Silenced expression of:

...

PhL: phosphorylase-L and R1 genes to reduce sugars needed for acrylamide
b
...

Reduced level of blackspot bruising
d
...
Maris Piper potato
1
...
Resists
Globodera rostochiensis
2
...

Survey markets for potato relatives (solanum species) within breeding range that are resistant to
nematodes
a
...
had to soak flower in salt solution to silence the compatibility mechanisms
b
...
2% elite genome and nematode resistance in 0
...

= 6
...

Modified crop traits

...
coli
i
...
Slow ripening tomatoes

...
inhibit enzymes that break down pectin; should still flavour but safer in transit
1
...

3
...
Still had colour and soluble solids, but more
nutritious because have higher antioxidant
levels
a
...

Frost tolerance in tomatoes

...

Proteins from flounder prevent ice crystal formation to stop freezing
2
...

toxic to root hair cells but adding lime once a year reduces problem

...

bacterial citrate synthetase gene into papaya, tobacco

...
Purple tomatoes high in anthocyanins

...

Anthocyanins protect against cardiovascular disease and cancers with anti-inflammatory activity

...
Increasing nutritional value
1
...

iron deficiency results in anemia and increased disease susceptibility
a
...
used seed storage protein promoter (GluB-1) so only expressed in seed
b
...
Carotenoid in rice: Golden rice

...

initially contained 1
...
put 3 genes in:
1
...
carotene desaturase
3
...
co-transformed into rice using agrobacterium
ii
...

Could have used plant breeding as some varieties have more carotene in them
3
...

stearate produced from partially hydrogenated oils: can these levels be increased without more trans
acids
a
...

could also be used to produce biofuels by making lipids behave like diesel

...
Better food storage

...

potato undergoes sweetening in cold storage

...
Expressed tobacco invertase inhibitor using CaMV 35S promoter: reduced hexose accumulation
5
...

modify sugars made by changing accumulation profile
a
...

recombinant miraculin in tomatoes so have reduced sugar content
6
...

antioxidants, protein content in cassava, vitamins
iii
...
pollutants concentrated in plant can be recycled

2
...

use for farming: increase crop yields
iv
...
Turn on constantly and get leaves heavier, and
larger, and increased plant dry matter productivity
...
Medicinally useful products
1
...

less care, no food, lot of labour and care costs
2
...

What crop to be grown
a
...

harvesting the leaves or seeds
c
...
Plantibodies

...
virus resistance
i
...
industrial filters
a
...
2 genes needed for heavy and light chain
...
antibody properly formed with same specificity giving 1
...

Applications of plantibodies

...

Vaccines

...
Epitopes expressed by fusion to coat protein of
cow-pea mosaic virus
2
...
HIV antigens have been made this way too so
good as not derived from blood so reduced risks
of hepatitis
a
...
Production of anticoagulants: Hirudin
1
...
Good as make
lot of protein and good harvesting facilities as
we know how to use them

...
Oleosins are proteins in the oil body and have
lipophilic stretch of amino acids
3
...
Transformed into oilseed rape and was possible
to purify product

...
If didnt have leader sequence
would be in with other protein
a
...
Laere 2016: Need to be careful because this has lowered production costs but different people would need
different doses so this should be monitored
iii
...
Use protein on outer coat to raise antibodies to
...

Aesthetics

...
Suppressed chalcone synthase and dihydroflavanol reductase to give white and blue colour
ii
...
No limits to horticulture and pharmacological uses

5
...
Tobacco Mosaic Virus

...
Disassembly and replication
1
...

knows in host because of pH and ionic strength of cell solution
2
...
Translation: Ribosomes bind to naked RNA and go to start codon, translate
and fall off at stop codon = 126K protein
4
...

these are the replicase proteins: 126K and 183K
5
...

bind to 3’ end of +ve sense RNA and make negative sense RNA
...

This acts as template to make full length genomic +ve sense RNA and Replicases can skip first part of
negative template and get shorter positive sense subgenomic RNA, ribosomes then bind and allows translation
of MP and CP: 30K and 17
...
Replication
iii
...
Coat proteins bind at origin of assembly and get encapsidation
iv
...
Use movement protein to expand plasmodesmatas so virus can get
through, can slo pump naked RNA through
v
...
reach phloem and this moves the virus all around plant
a
...
plant healthy seeds and tubers
1
...
keep plants virus free
1
...
but concern to environment
ii
...
viruses mutate rapidly and overcome natural resistance
b
...
mild strain inoculated against water control
i
...
Risks: can mutate and mild virus turn nasty
c
...
Coat protein mediated resistance
1
...
tumefaciens and boom
2
...

Papaya ringspot virus: used CPMR was very effective
3
...

less resistance with mutant CPs, more with better stability
a
...
Only plants with
accumulated CP in upper epidermis- site of infection showed resistance
...

Very specific: resistance related to amino acid homology between virus and CP
i
...
WT MP accelerated symptoms, remove amino acids from 3’ terminus
means it doesnt function


...

worked against related tobamoviruses
b
...
54K protein resistance
1
...
Couldnt detect it in infected plants
3
...

differed to CP-MR:

...
CP broke down with large inoculum
ii
...
Replicase proteins resistance
1
...
partial replicase gene in got some resistance
d
...
Risks associated with coat protein mediated resistance
1
...
Risks to environment

...
transgenic synergism
i
...
recombination
iii
...
Commercial risks
i
...
insertion site

...
Selection

...
CaMV promoters

...

Viruses have dsDNA genome which is replicated through RNA by reverse transcriptase
...

b
...
Synergism

...
POTYVIRUS AND CRINIVIRUS
...

also TMV and Potato virus Y (potyvirus) in surfina

...
heteroencapsidation: potyvirus transmitted by
aphids, TMV isnt
2
...

already happens in nature
a
...

no exchange of genetic material so effects likely transitory
5
...

viruses exchange RNA in 3 ways:

...
aberrant homologous
ii
...


all occur naturally and to some extent in
transgenic lines

6
...

Synergism

...

transencapsidation

...

recombination

...
Post transcriptional gene silencing

...
aphid transmitted, with positive sense RNA, auto proteolytically cleaved to
give 9 viral proteins
2
...

resistant plants generated and had no RNA in cytoplasm and the more virus was thrown at the plant
the more resistant it became
a
...
POST TRANSCRIPTIONAL GENE SILENCING

...

Transgenic plants resistant to PVY have many PVY transgenes that seem highly transcribed but
accumulate low levels of the transcript: resistance regulated by a cellular pathway that down regulates
overexpressed mRNAs
b
...
aberrant RNA triggered this system that gives low steady state levels of the transgene RNA (like CP) when virus
with same sequence enters plant it is targeted for elimination
i
...
Can take any part of virus, put in nucleus, screen for transgenic plants
1
...

RNA high level, plant convert it to dsRNA and dicer enzyme cuts it into siRNA fragments 21bp long
...
when transform plants now put in piece of RNA
1
...
no synergism as no protein
3
...
Mubin 2019: PV2 protein encoded by papaya leaf curl virus renders it
unsusceptible to Transcriptional gene silencing and PTGS
f
...
not used as mechanism to look at plant processes
i
...
Develop plants using this technology to silence genes
1
...
How do we get virus infections then?

...
but this is a bad virus as it destroys its host, a good one keeps it alive
ii
...
mutated movement proteins give resistance and bind to plasmodesmata
but most of time RNA is destroyed so how do you get the protein
expressed in transgenic plants?

...

Some plants have high levels of expression but not crossed the threshold so select for these and
expressing required protein
h
...
not needed by virus but they need the virus for all functions necessary for multiplication and spread through
plant
i
...
in the SAT-RNa of CMV the effect is seen in the symptoms produced in
infected plants
1
...
SAT-RNA of CMV
1
...
but when transgenic plants infected with CMV, the transcribed SAT-RNA
was replicated and accumulated to high levels and could attenuate
symptoms
3
...
Ribozymes

...
Self splicing reactions: remove an intron from pre-ribosomal RNA of
tetrahymena
...
Self cleaving reactions: reactions occur during replication of certain viroids
and SAT-RNAs
...
Each has hammerhead structure containing conserved bases flanking the self cleavage site
ii
...
works but not efficient because they dont recycle so if virus is strong it will outweigh ribozymes
j
...
short half life
i
...

Ribozymes flanked 5’ and 3’ end of sgRNA to cleave and release sgRNA

6
...
ultimate construct to give resistance to multiple viruses in one transformation
a
...
proteins secreted by animal cells after viral infection during cell proliferation, induce the synthesis of
additional proteins that lead to the inhibition of virus multiplication
i
...
once active it synthesises an oligonucleotide 2-5A which activates a latent endoribonuclease (RNaseL) which
degrades viral and cell RNA
iii
...
When virus present it generates the oligonucleotide
which activates RNaseL degrading all RNA in cell
1
...
Take genes for 2-5A synthetase and RNaseL and transform into plant: 2 genes on one construct
1
...
manifested as necrotic lesions on leaves as some viruses trigger
hypersensitive responses causing necrosis as viruses cant live in dead cells

...

PTGS + 2-5A synthetase + RNaseL = protection
b
...
animals and humans infected with plant virus have antibodies against it due to recombination
i
...

2
...

Construct: Kanamycin resistance, expression cassette, 35S promoter, heavy
and light chain with protein linker


...

put in plant, got resistance in inoculated leaf but lot of resistance in upper leaves so harder for virus
to move
b
...
F8 antibody had highest affinity for AMCV coat protein
i
...
GDD appears in every replicase sequence of
viruses in the world, make antibodies against it
and inhibits replicase
3
...

produce new drugs and new medicines

...

used with ebola
b
...

wont transmit disease
d
...
Problems with using mammal genes in plants

...
does it make it non vegetarian
i
...
spend lot of time screening for GM plants for allergic reactions
iii
...
Viral elements used in plant biotechnology

...
CaMV has 2 promoters in genome

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constitutive expression in all tissues
i
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put in viral translational enhancer to get gene at high levels
2
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omega: from 5’ terminus TMV down to first AUG of replicase gene and maximises production of the
replicase proteins: 50x more protein
ii
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add coat proteins so stable and use to deliver nucleic acids into human
cells like gene treatments
iii
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cut out target sequences from viroids
iv
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EG potyvirus NI proteins

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need millions of coat protein but few replicases, use the nucleus as a dump for replicases and excess
proteins using a nuclear targeting signal (protein)
b
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why do we want this?

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TF genes on, mRNA into cytoplasm, translated to
TF to migrate back to nucleus to switch on gene
i
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Viral Vectors

1
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High level expression of foreign proteins

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Presentation of heterologous peptides eg vaccine production

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Take virus want to raise antibody to on outside of CP, infect
plant with construct and TMV reaches high levels
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Functional genomics (VIGS)
vi
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considered to be bad because viruses do it
2
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transformed with 35S construct and a suppressor; nothing trying to destroy the RNA so get high levels
a

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