Genetically modified plants for fatty acids

1. Genetic Engineering of plants
for Fatty-acid composition

2. Genetic engineering......?
 Is a type of genetic modification.
 purposeful addition of a foreign gene or genes to the
genome of an organism.
 not bound by the limitations of traditional plant
breeding.
 physically removing the DNA from one organism
and transffering the gene(s) for one or a few traits
into another.
 Overcomes the 'sexual' barrier between species.
 traits from any living organism can be transferred into
a plant.
 more specific in that a single trait can be added to a
plant.

3. Genetic engineering in action
 Genetic engineering comes to action where
Plant breeding has its limitations.
 Overcomes sexual incompatibility, resulting
in addition of new traits to a species.
 When plants are crossed, many undesirable
traits are transferred along with the trait of
interest.

4. STEPS INVOLVED IN GENETIC
ENGENEERING OF PLANTS….
Step 1: DNA Extraction
A sample of an organism containing the
gene of interest is taken through a series
of steps to remove the DNA.

5. Step 2 : Gene Cloning
Extraction of the gene of interest
from the rest of the genome and
making multiple copies of it.

6. Step 3 : Gene Design
Done in a test tube by splicing the gene apart
with enzymes and replacing the regions that
have been extracted.

7. Step 4 : Transformation
Inserting new gene into some of the cells
using different techniques
Some of the common methods include the
gene gun, agrobacterium, microfibers, and
electroporation.
The main goal is to transport the new
gene(s) and deliver them into the nucleus of
a cell without killing it.

8. 1.Transformed plant cells are then regenerated into transgenic plants.
2.The transgenic plants are grown to maturity in greenhouses
Step 5 : Backcross Breeding
1. Transgenic plants are crossed with elite breeding lines to combine the
desired traits of elite parents and the transgene into a single line.
2.Offsprings are repeatedly crossed back to the elite line to obtain a high
yielding transgenic line.
3.Results in a plant with a yield potential close to current hybrids that
expresses the trait encoded by the new transgene.

10. MODIFICATION ACHIEVED ENZYME ENGINEERED SOURCE OF GENE AND
REFERENCE
Lauric acid production Acyl-ACP thioesterase California bay ,Voelker et al, 1992
lncreased stearic acid Antisense of stearoyl-ACP
Stearyl-COA desaturase
Brassica napus, ,Knutzon et al., 1992
Rat, Crayburn et al.
Reduced saturated fattyacids Stearyl-COA desaturase
3-Ketoacyl-ACP synthase II
Acyl-ACP thioesterase
Yeast ,Polashock et al,
Castor, Bleibaum et al,
Soybean ,Yadav et al,1993
Reduced saturated fattyacids in
phosphatidylglycerol
Acyl-ACP:glycerol-3-phosphate
acyltransferase
Squash,Arabidopsis, Murata et al., 1992
lncreased saturated fattyacids in
phosphatidylglycerol
Acyl-ACP:glycerol-3-phosphate
acyltransferase
Escherichia coli ,Wolter et al, 1992.

11. Petroselinic acid production.
Acyl-ACP desaturase Coriander ,Cahoon et al., 1992
Increased-a-linolenic acid w3 desaturase Arabidopsis, Arondel et
al.,1992;Yadav etal.1993
Cyclopropane fatty acid Cyclopropane synthase Escherichia coli,Schmid1993
y-Linolenic acid production Linolenic Ab desaturase Synechocystis, Reddy et al., 1993
increased oleic acid production ACP:protein A fusion Spinach Lee et al., 1993

12. MODIFYING GENE FOR FATTYACID COMPOSITION
Understanding and manipulating the biochemistry of oil biosynthesis,
and cloning of the genes encoding the enzymes involved in fatty acid
modification and oil accumulation
Produces "designer" plant seed oils with improved nutritional.
Includes overexpression or suppression of genes encoding single or
multi-step biosynthetic pathways
 assembles the complete pathway for the synthesis of long-chain
polyunsaturated fatty acids.

13.  transgenic plant oils represent the first success in design of modified plant products.
 Directed gene down-regulation strategies have enabled the specific tailoring of
common fatty acids.
 diacylglycerol acyltransferase 2, which catalyzes the final step in triacylglycerol
assembly, is an important contributor to the synthesis of unusual fatty acid.
 increasing the accumulation of Δ12-modified fatty acids synthesized by transgenically
expressed FAD2-like enzymes is popular .
 biochemical analysis of plants that express introduced fatty-acid metabolic pathway
ensures the removal of novel fatty acids from their site of synthesis on
phosphatidylcholine which enable further modification, exclusion from membrane
lipids and accumulation in seed triacylglycerols containing oils.

14. Some works done
 Genetic modification now makes it possible to improve the composition and
properties of oils from different plants far more quickly and precisely.
 The first genetically modified vegetable oil has a high proportion of lauric
acid - desirable for many food and non-food applications
 Recently a new soybean has been developed, producing less saturated and
more heat stable oil, thus has a healthier fatty acid composition
 Rapeseed oil is rich in monounsaturated fatty acids. But a different fatty acid
composition would be better for some applications.

15.  Genetic engineering could be used to optimise the fatty acid composition of
rapeseed oil
 Rapeseed can be used to produce certain emulsifiers, vitamin E, and substances
that can help lower cholesterol levels.
 Genetically modified rapeseed could be developed with a higher content of
long-chain fatty acids as fatty acids with longer side chains remain solid at
higher temperatures.
 There is a wide and diverse range of unusual fatty acids in the seed oil of many
wild plants. with unknown biological role, but may have a role in defence
against pests.

16.  sources of these unusual fatty acids cannot be produced economically on a
commercial scale.
 Hydroxy, epoxy, conjugated, acetylenic, very long chain, medium chain and
branched chain fatty acids and liquid waxes are among the industrial targets of
greatest interest.
 Oils high in hydroxy fatty acids can be produced from castor and Lesquerella ,
but it could be produced more economically on a large scale currently with
canola or soybeans engineered with genes for such metabolism
 Genes for most of these unusual fatty acids have been cloned.