Issues of transgenic on crop and current position of transgenics in india and world

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WELCOME
Ekatpure Sachin Chandrakant
MSc. Agricultural Plant Biotechnology

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Nuclear Crisis in Japan

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Prospects and issues of TransgenicsProspects and issues of Transgenics
in Agriculturein Agriculture
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Outline
 What is a transgenic?
 What is recombinant DNA technology?
 Requirements for transgenics
 Typical gene construct
 Steps in transgenic plant production
 Global status of trangenics
 General applications of transgenics
 Biosafety regulations for GM crops
 Possible consequences of transgenics
 Future prospects of transgenics
 Conclusion
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5. 5 5
The genetic
material in living
organism
Uniqueness of
DNA

6. What is a transgenic?
 Exotic gene added to a species through recombinant DNA
technology - Transgene
 The organism that develop after successful transformation
- transgenic
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BT COTTON GOLDEN RICE FLAVR SAVRROUNDUP READY

7. A TYPICAL GENE CONSTRUCT
Promoter
Marker gene
Transgene
Reporter gene
Terminating sequence
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8. Recombinant DNA technology
 Production of a unique
DNA molecule
 Joining together two or
more DNA fragments not
normally associated with
each other
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9. 9
Requirements for transgenics
 Gene of interest
 Vector
 Host
 Gene delivery system
 DNA modifying enzymes
 Plant regeneration system (tissue culture) 9
(Agrobacterium)
(Gene gun)
Indirect
Direct

10. 10
Steps in transgenic plant production
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NATURAL
INDUCED
Kanamycin

11. 11(James, 2011)

12. 12(James, 2011)

13. 1313
Approved for commercial
cultivation
BT COTTON
Moratorium for environmental
release
BT BRINJAL
Under various stages of field trials
COTTON,BRINJAL,CABBAGE,
GROUNDNUT, PIGEON PEA,
MUSTARD, POTATO, SORGHUM,
TOMATO, TOBACCO, RICE, OKRA
and CAULIFLOWER
(Genes: Cry1Aa, Cry1Ab, Cry1Ac,
Cry1F, Cry1B, Cry2Ab)
IIndian status of transgenics

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Applications of Transgenics in Agriculture
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15. Directorate of Weed Science Research, 2010
Factors contributing to crop loss
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Herbicide tolerence
 Weed control - biggest challenge in crop production
 Reduce crop yield and quality (37 per cent)
 Transgenics offer tolerance to herbicides
eg. Roundup Ready soybean - glyphosate
T25 Maize - glufosinate
Roundup Ready Cotton - glyphosate
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+ Glyphosate
X
Roundup Sensitive Plants
X
X
Shikimic acid + Phosphoenol pyruvate
3-Enolpyruvyl shikimic acid-5-phosphate
(EPSP)
Plant
EPSP synthase
Aromatic
amino acids
Without amino acids,
plant dies
X

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Bacterial
EPSP synthase
Shikimic acid + Phosphoenol pyruvate
3-enolpyruvyl shikimic acid-5-phosphate
(EPSP)
Aromatic
amino acids
Roundup Resistant Plants
+ Glyp
hosate
With amino acids,
plant lives
Roundup has no effect;
enzyme insensitive to
herbicide

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Soybean without Roundup spray Soybean with Roundup spray
Roundup Ready soybean

20. Cost/benefits of HTGM Soybean
(ISSAA, 2008) 20
Year
Cost
savings
($/ha)
Net cost
saving/increase in
gross margins,
inclusive of cost of
technology ($/ha)
Increase in
farm income at
a national level
($ million)
Increase in
national farm
income as a % of
farm level value of
national
production
1996 25.2 10.39 5.0 0.03
1997 25.2 10.39 33.2 0.19
1998 33.9 19.03 224.1 1.62
1999 33.9 19.03 311.9 2.5
2000 33.9 19.03 346.6 2.69
2001 73.4 58.56 1298.50 10.11
2002 73.4 58.56 1421.70 9.53
2003 78.5 61.19 1574.90 9.57
2004 60.1 40.33 1096.80 4.57
2005 69.4 44.71 1201.40 6.87
2006 81.7 56.96 1549.40 7.51
2007 82.7 57.96 1358.20 5.76

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Insect resistance
 “Bt” - Bacillus
thuringiensis
- A soil bacterium with
crystalline (cry) protein
which transforms to δ
endotoxin in insect gut
 In Bt crops, different cry
genes incorporated for
insect resistance
2121

22. Impact of Bt cotton in India
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Cost/benefit analysis of Bt cotton
(ISAAA, 2009 )

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(Neilsen, 2003)
Cost/benefit analysis of Bt cotton contd….
State
Pesticide
reduction
Yield increase Net profit
/ha % Q/ha % /ha %
Andhra Pradesh 4,594 58 4.9 24 12,717 92
Karnataka 2,930 51 3.3 31 6,222 120
Maharashtra 2,591 71 3.6 26 5,910 66
Gujarat 3,445 70 2.9 18 8,564 164
Madhya Pradesh 2,200 52 5.4 40 9,594 68
Average 3,202 60 4.2 29 7,737 78

25. Virus resistance
 No valid control measure for viral diseases in plants
 Various approaches used
in transgenics
 Antisense mediated
 Satellite RNA
 Ribozyme mediated
 Coat protein mediated
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Papaya ringspot resistance

26. GM Papaya in Thailand

27. Virus resistant transgenic plants
CMV infected CMV resistant (GM)
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Crop Virus
Tobacco Tobacco mosaic
virus
Potato Potato virus x
Tomato Tomato yellow
leaf curl virus
Maize Maize dwarf
mosaic virus
Rice Rice strip virus
Citrus Citrus tristeza
virus

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Disease resistance
 A large number of plant defense genes encoding
antimicrobial proteins have been cloned
eg. Chitinase and glucanase
 Breaks chitin and glucan in the cells of fungal pathogen
 Other antimicrobial proteins - Thionin, Lysozyme,
Polygalacturonase inhibitor
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Disease resistant transgenic plants
Crop Gene transferred Controlled pathogen
Tobacco Bacterial chitinase Alternaria longipes
Chitinase Rhizoctonia solani
Potato 1,3,-beta glucanase Phytophthora
infestans
Tomato Chitinase Fusarium oxysporum
Tobacco Ribosome
inactivating protein
Rhizoctonia solani

30. GM Grapes

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Quality improvement
 Long term storage for tomato
Antisense technology
(polygalacturonase)
 Golden Rice - enhanced vitamin A and
Fe content
 Golden rice 1 - 1.6 μg/g β carotene
 Golden rice 2 - 37 μg/g β carotene
 Golden rice 3 - + 7 fold iron content

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The Golden Rice Production
IPP
Geranylgeranyl diphosphate
Phytoene
Lycopene
β -carotene
(vitamin A precursor)
Phytoene synthase
Phytoene desaturase
Lycopene-beta-cyclase
ξ-carotene desaturase
Daffodil gene
Single bacterial gene;
performs both functions
Daffodil gene
β-Carotene Pathway Genes Added
Vitamin A
Pathway
is complete
and functional
Golden
Rice

33. Transgenic flowers with longer vaselife
 Post harvest life of flowers
-ethylene based
 Transgenic carnations expressing
antisense ACC oxidase
 Dianthus caryophyllus- approved in
Australia
(Tanaka et al., 1998)
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34. Transgenic plants as bioreactors
 Act as living bioreactors - Molecular
pharming
 Inexpensive production of chemicals
and pharmaceuticals
 Carbohydrates, fatty acids, proteins,
vaccins (edible)
 Transgenic banana, tobacco and
potatoes for hepatitis B virus
vaccine 34(Giddings et al., 2001)

35. 35
Overview of Molecular Pharming
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MOLECULAR PHARMING

36. Biosafety of GM Crops
Policies and procedures adopted to ensure environmental safety
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Genetic manipulations - against nature !!!

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Safety assessment approach for GM crops
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Elements of assessment
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Regulatory framework in India
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40. Possible consequences of transgenics
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Risk of toxicity/allerginicity
 Addition of new genetic material
may activate toxic pathways
 Appearance of novel metabolites
 Introduction of new protein
 Non-immunogenic protein could
become immunogenic
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(Kaeppler, 2000)

42. Brazil nut allergy in soybean
 A well-known case of GM soya
allergy
 2S albumin gene from Brazil nut to
soybean for enhanced methionine
(Julie et al.,1996)
 Allergen transferred unintentionally
from Brazil nut to GM soya
 Investigations with GM soya revealed
immune reactions in people with
Brazil nut allergies
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Impact of marker genes
 Marker gene could induce antibiotic resistance
 Would reduce effectiveness of antibiotics to fight diseases
 Possibilities for HGT (horizontal gene transfer) :
 DNA must be free from the cells
 Bacterial recipient must be competent
 Sequence homology for integration
 Acid environment of human stomach is not congenial
 HGT of nptII gene can occur 1 in 10 billion
 Specificity of promoter 43(Redenbaugh et al.,2008)

44. Use of promoters of virus origin
 Concerns expressed regarding promoter sequences
eg. 35S promoter of CaMV
 If it invades human cells and turns on certain genes !!
 Probability is very low and no such report so far
 Current process – tissue specific/plant based promoters
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45. Eating of foreign DNA
 DNA present in all living things and
eaten by humans with every meal
 Broken down during digestion process
 Small amount absorbed in blood stream
or excreted
 According to WHO, amount of DNA
ingested- 0.1 to 1 g/day (novel DNA
represents 0.0001%)
(Chawla, 2009) 45

46. Changes in nutritional elements
 Accidental changes in nutritional component of GM crop
 Roundup Ready soybean produces large quantities of
phytoestrogen (causes breast cancer) after glyphosate
spray ??
 Investigation revealed no such increase
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(SAG report, 2000)

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Gene Flow
 Accidental cross between GM plant and traditional varieties
 Contaminate local variety with transgene
 35S promoter sequence found in non GM Maize in Mexico
(Chapela, 2001)
 CIMMYT amplified 28 accessions from Oaxacan landraces
with CaMV 35S promoter primer
 Samples did not show presence of 35S promoter
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(Gaur et al., 2010)

48. Creation of superweed
 GM crop may hybridize with weedy
relatives
 Transgene may be transferred
eg. Ryegrass highly resistant to
glyphosate found in Australia
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49. Strategies to prevent gene flow
 Isolation zone
 Trap crop
 Male sterility
 Chloroplast
transformation
 Clean gene technology
- Devoid of vegetation
- Use of non-transgenic variety
- Inactive pollens
- Gene construct introduced into
chloroplast genome
- Markerless GM
49(Chawla, 2009)

50. Resistance of target species
 Insect/ virus population
rapidly adapt to
environmental pressure
 Development of new strains
 Gene pyramiding - Best
solution
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51. Impact on biodiversity
 Reduction in genetic diversity by
development and global spread of
improved varieties
 Sustainable agriculture depends on
mixed cropping and crop rotation
 Not unique to GM but is relevant to
all improved varieties
 Bt protein is highly unstable &
rapidly degraded in stomach juices
of vertebrates and in soil 51

52. Monarch butterfly incidence
 Monarch butterfly caterpillars died when fed on Bt maize
pollen
 It was a lab experiment
 Butterfly fed only on Bt maize
 For toxic effect of Bt protein it should meet specific dose
requirement
 In nature it is not possible to meet that dose level
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(Losey et al,1999)

53. Warangal Attempt
 Cattle and sheep dying on consuming Bt
cotton plants in Warangal Dist. of
Andhra Pradesh??
 No one has so far conclusively proved
that Bt protein in the Bt cotton plants
was the real culprit
 Why do the cattle die eating Bt cotton
only in the Warangal region of Andhra
Pradesh ?
 Clearly a mischievous and cheap
attempt (Rao, 2007) 53

54. Ethical issues
 Unacceptable intervention in
“God’s creation” violating
barriers in natural world!!
 Objections to consuming
animal genes in plants and
vice-versa
 Most species already share a
very significant amount of
common genetic material.
Man & chimpanzee - 99.4%
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55. Future prospects
 From 2011 to 2015 about 12 new countries projected to
adapt GM crpos
 Golden rice expected in 2013
 In north America herbicide tolerant wheat expected to be
ready by about 2017
 GM potato for late blight resistance
 New events ready for playing role against climate change
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56. Still confused?
Transgenic Cisgenic
Choice is yours
Wild relative
No risk of gene flow
No risk of foreign DNA
No risk of allergy
No ethical issue
Fewer biosafety testing
Unrelated organism
Risk of gene flow
Risk of foreign DNA
Risk of allergy
Ethical issues
Biosafety testing
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57. 57
Conclusion
 Transgenic crops have potential to solve world’s hunger
and malnutrition problems
 Safety testing and regulations can ensure its superiority
 The society should be enlightened about the scientific
technology
 Newer and faster techniques required to evaluate
transgenic products
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58. Thank you…