What is Biotechnology?

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22 Οκτ 2013 (πριν από 3 χρόνια και 5 μήνες)

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What is Biotechnology?

1.

An ever expanding set of biological techniques or
tools

2.
Tools are

applied for the development of
new
knowledge,
but also

products or services.

3.
Can involve

any organism
(bacteria, plants,
yeast/fungi, animals, humans).

4.

Biotechnology is a big
industrial sector

5.
Intersects with bioengineering, food technology,
health delivery, agriculture, biodiversity
preservation, etc



Plant or crop biotechnology is not the
same as genetic engineering (GMOs)

“Biotech crops” or “biotech microbes” are produced by
recombinant DNA technology. Such organisms have
unique properties and their release into the
environment is subject to special regulations.


GMO
G
enetically
m
odified
o
rganism

Biotech crops, biotech foods

Genetically engineered food


The methods of biotechnology are
universally applicable to microbes,
animals and plants


Genome sequencing


Gene expression profiling


Identification of biomarkers


Fermentation technology


High
-
troughput screening


Bioinformatics


Cell culture

Agricultural or plant biotechnology
has many facets.


Use of genetic markers to accelerate plant breeding.


Selection of microbes that live symbiotically with
plants (e.g. nitrogen fixers).


Metabolic flux engineering to enhance the production
of specific chemicals in plants or in tissue culture.


Diagnostics for pathogens or toxins


Creation of biopesticides and bioherbicides


Creation of crop varieties or biomass varieties with
specific application in agriculture or industry.

Guauyle, a native of the
desert of Chichuahua is
the source of hypo
-
allergenic latex

(latex with a very low
protein content)



Finding interesting chemicals in unusual plants!

Biopesticides: an under
-
developed $ 100 million market

Eden Bioscience developed

Messenger
, a protein that

activates the natural plant

defense pathways.

A model for the biopesticide industry:

More local development and production

Bt Biopesticide

Pathogen diagnostics


Potato: PVX, PVY, PVA, PVS, PVV, TSWV and Ralstonia solanacearum

• Plum tree, Peach tree, nectarine, apricot tree, cherry tree and Prunus
spp. ornamentals: Plum pox virus (PPV)

• Tomato and pepper: PepMV, ToMV, TSWV, TYLCV

• Geranium: R. solanacearum and Xanthomonas hortorum pv pelargonii

• Ornamentals (also a wide range of fruit trees and horticultural): INSV,
TSWV, CMV

• Beetroot: BNYVV y BYV

Finding smart green chemicals: high
trough
-
put screening.

1.
Chemical library

2.
Specific assay

3.
Detectors

4.
Data storage

5.
Robots


Most agrochemicals are very broad spectrum; kill many species

of insects or nematodes; can we find species
-
specific chemicals?

Start with genes (e.g. encoding receptors active in important

signal transduction pathways) and then screen chemical libraries

for chemicals that interact with the receptor.

Biological diversity
:

All human beings have
the same genes, but we
all have very slight
differences in many
genes (SNPs).
Similarly, individual
plants of a species differ
slightly.

Some of these
differences are
important, but how do
we find them?

Estimating biological diversity:

Finding new alleles.

Modern maize is a descendent of
teosinte,
a plant with
multiple stems, very small ears with few seeds encased in a
hard shell.

It is likely that domestication occurred in a relatively small region (a few villages)

and that teosinte grew in a larger area. Genetically this means that alleles of

many genes are present in the wild populations of teosinte now growing in Mexico,

but these alleles are not in domesticated corn.

Wild species

Early domesticates

Modern varieties

Figure 1

Loss of genetic diversity (alleles) as a result of domestication,

selection and plant breeding.

Alleles are variants of the DNA sequence at a
specific locus. They can be due to small deletions,
insertions or base changes. They may or may not
have an effect on the phenotype.

Single nucleotide polymorphisms (SNPs or “snips”)

are single base changes. They can be easily
identified once the genome has been sequenced.

Change of a single base occurs about every 500 bases.
Most of these replacements have no effect (they are
outside a gene, or produce a silent mutation).

Other snips impart a different activity to the gene. Some
snips show up as changes in phenotype (human
disease, plant resistant to infection, a more or less
efficient enzyme for example)

Mass characterization of alleles by detection of SNPs (single

nucleotide polymorphisms) in a 100,000 plants annually.

Courtesy of Pioneer Hi
-
Bred, a DuPont Company

A. In the field, a technician samples a leaf with a hole
-
punch putting

the leaf disc immediately in a plastic tube with DNA
-
extracting solution

which is put in a rack (B). C. After extracting the DNA, a robot samples 144

tubes simultaneously and transfers aliquots to filters that are hybridized with

nucleotide probes (D). Spots have different intensities depending on sequence.


Lycopersicum esculentum

Lycopersicum peruvianum

X

One of the many progeny is bigger!

Finding interesting genes in wild relatives

Genome Sequencing

Important genes identified in one species
(Arabidopsis or rice)

can immediately be recognized in other
species. All this information is
public.


Expression Profiling

Determine the expression of thousands
of genes at once on a “chip”


Proteomics


Genomics, the most recent genetic technology

Making a linkage map with

molecular markers permits acceleration of
breeding because plants carrying the desirable
gene (between the flags!) can be identified as
seedlings. No need to wait for the phenotype to
show up in the field.





Gene mapping and

Marker assisted selection (MAS)

Genetic engineering of plants (creation of GMOs)
relies on a natural gene transfer mechanism by
Agrobacterium tumefaciens

from its Ti plasmid to the
plant genomic DNA.

Discovered by Marc Van Montagu and Jeff Schell in Belgium
and by Mary Dell Chilton and Eugene Nester in the USA

http://www.ejbiotechnology.info/content/vol1/issue3/full/1/bip/

Crops expressing the Bt gene (Cry) require fewer pesticide
applications, which is better for the environment and saves the
farmer money.

The entire GM crop business is

driven by two genes: for insect

resistance and herbicide tolerance

Herbicide tolerant crops promote conservation
tillage.

Plants are left on the field to decay more slowly than if they are
mixed with the topsoil. Water is conserved (less evaporation
and stubble retains more snow on the field.). Less soil
compaction from heavy machinery. Less dust (dust is a serious
pollutant).

Less work! It saves the farmer money!

Biotech Crops
-

Planted by 7 million
Farmers in 18 countries in 2003

canola

cotton

corn

soy

Million Acres

0

20

40

60

80

100

120

140

160

180

200

Benefits Drive Global Expansion of GM crops.


>10% annual growth since 1996 introduction

Annual impact of current
and potential biotech
products on US agriculture



Pesticide Reduction


46 M lbs actual


117 M lbs potential



Food and Fiber Supply



4 B lbs actual


10 B lbs potential



Economic Return


$1.5 B actual


Additional $1.0 B potential

Source: Gianessi et al., 2002. NCFAP
(National Center of Food and Agricultural Policy)

Potential: Represents the added impact of products in the development pipeline

Source: C. James, 2003. ISAAA
(International Service for the Acquisition of Agri
-
Biotech Applications)