A transgenic crop plant contains a foreign gene or group of genes which have been artificially inserted instead of the plant acquiring them through pollination. Up to 17 million farmers in 24 countries planted 189.8 million hectares (469 million acres) in 2017, an increase of 3% or 4.7 million hectares (11.6 million acres) from 2016.

1. WELCOME

2. JAYANT YADAV
2017A39D
CCS Haryana Agricultural University, Hisar

3. Insect pest
resistance
Disease
resistance
Herbicide
resistance
Nutritional
improvement
Abiotic stress
resistance
Production of
edible
vaccines
TRANSGENIC CROPS
A transgenic crop plant contains a foreign gene or group of genes which have been
artificially inserted instead of the plant acquiring them through pollination. Up to
17 million farmers in 24 countries planted 189.8 million hectares (469 million
acres) in 2017, an increase of 3% or 4.7 million hectares (11.6 million acres) from
2016.

4. Current and Future GM Crop Traits
1. Insect Resistance (Plant Incorporated Protectants) – ex: Bt corn &
cotton
2. Herbicide Tolerance – ex: Glyphosate Resistant Corn & Soybeans
(i.e. Roundup Ready), cotton
3. Stress Tolerance – ex: drought, salt resistant varieties
4. “Value Added” Crops -–ex: Golden Rice containing vitamin A
5. “Biopharming” – ex: Production of drugs, chemicals on
agricultural scales

6. Global Area of Biotech Crops, 2016-17: By Crop (mh)

7. Biotech Soyabean
(34.05 Mha)
45%Biotech Maize
(33.84 Mha)
45%
Biotech Cotton
(4.58 Mha)
6%
Biotech Alfalfa
(1.22 Mha)
2%
Other Biotech
crops* (1.31 Mha)
2%
Biotech crops planted in the USA, 2017
* Biotech canola, biotech sugar beets, biotech potato, biotech apples, biotech squash,
and biotech papaya

8. Global area of Biotech crops, 2016-17: By trait (Million Hectares)

9. Economic benefit gains and productivity at the farm level

10. Approaches to develop insect resistant transgenics
Two main approaches
 Integration of δ-endotoxin genes derived from
various subspecies of Bacillus thuringiensis
(Bt)
 Integration of plant genes encoding for
production of enzyme inhibitors and sugar
binding lectins etc.

11. Methods of genetic transformation
A) Indirect gene transfer (Vector-mediated)
• Agrobacterium-mediated gene transfer
B) Direct gene transfer (Vector-less)
• Polyethylene glycol (PEG) mediated gene transfer
• Electroporation
• Microinjection
• Micro projectile bombardment

12. General Methods of Producing Transgenic Plants

13. 1985
1992
1988
1994
1998
1996
1999
2000
1st transgenic plants produced
Particle bombardment developed
GM crops considered substantially equivalent to hybrid varieties
Flavr-Savr tomato is released
Herbicide- and insect-resistant crops approved for cultivation maize,
Soybean, cotton
4.3 million acres of GM crops planted
GM food is dangerous
Monarch butterfly paper causes uproar
GM corn is excluded from its baby food
Greenpeace starts anti-GM campaign
75 million acres of GM crops planted
Golden rice with ß-carotene developed
McDonald’s rejects GM potatoes
Time line of GM Crops

14. 2006 GM crops cultivation reached 100 mha world wide
2014 Bt Brinjal released in Bangladesh
181.5 million hectares of GM crops planted world wide
Bt cotton released in India grown in 50,000 ha2002
Bt cotton II released in India for controlling Spodoptera &
Helicoverpa
2010 Govt .of India imposed moratorium on Bt Brinjal Event EE-I
GEAC recommended commercial release of Bt Brinjal Event EE-12009
Time line of GM Crops in India

15. INSECT CONTROL WITH GM CROPS

16. Koundal and
Rajendran
(2003)
CLASSIFICATION OF IR-TRANSGENES
Bt genes
Protease inhibitors (PI) genes
α-amylase inhibitor genes
Lectin genes
Enzyme genes

17. 1. What is Bt .....?
 Bacillus thuringiensis
• Gram positive
• Spore forming bacterium
 Upon sporulation, B. thuringiensis forms crystals of proteinaceous insecticidal δ-
Endotoxins (Cry toxins) which are encoded by Cry genes

18. Timeline of Bt
1901 Shigetane Ishiwatari first isolated the bacterium Bacillus
thuringiensis as the cause of the sotto disease
1915 Berliner reported the existence of a crystal within Bt, but the
activity of this crystal was not discovered until much later
1956 Researchers Hannay, Fitz-James and Angus found that the main
insecticidal activity against lepidoteran (moth) insects was due
to the parasporal crystal
1958 In the US, Bt was used commercially
1961 Bt was registered as a pesticide to the EPA
1996 Bt cotton was introduced into US agriculture
2002 Bt cotton was introduced in India

19. Types of crystal proteins and target insects
δ-endotoxin Crystal
proteins
Molecular weight Target insect
Cry1 130 kDa Lepidoptera
Cry2 70 kDa Lepidoptera and Diptera
Cry3 70 kDa Coleoptera
Cry4 130 kDa Diptera
Cry5 30 kDa Lepidoptera and
Coleoptera

20. Mode of action of Bacillus thuringiensis in Lepidoptera

21. Crop Gene(s) Target insect pests
Alfalfa cry1C Spodoptera littoralis
Broccoli cry1C Plutella xylostella, Trichoplusia ni,
Pieris rapae
Canola cry1Ac Helicoverpa zea, Spodoptera exigua
Chickpea cry1Ac Helicoverpa armigera
Cotton cry1Ab, cry1Ac, cry2Ab Helicoverpa armigera, H. zea , Heliothis
virescens, Pectinophora gossypiella, S. exigua,
Trichoplusia ni
Groundnut cry1Ac Elasmopalpus lignosellus
Egg plant cry 3b
cry1Ac
Leptinotarsa decemlineata
Leucinodes orbonalis
Maize cry1Ab, cry1Ac, cry1F,
cry9C, cry3Bb,
cry34Ab/cry35Ab
Ostrinia nubilalis,, Busseola fusca, H. zea, S.
frugiperda
Diabrotica virgifera
Poplar cry1Aa Lymantria dispar
Transgenic Crops Carrying Bt Genes for Insect Resistance

22. Crop Genes Target insect pests
Potato cry1Ab, cry1Ac
cry3A, cry3B
Phthorimaea operculella,
Leptinotarsa decemlineata
Rice cry1Ab, cry1Ac, cry2Aa Chilo suppressalis, Cnaphalocrocis
medinalis, Scirpophaga incertulas
Sorghum cry1Ac C. partellus
Soybean cry1Ac H. virescens, H. zea
Sugarcane cry1Ab Diatraea saccharalis
Tobacco cry1Ab, cry1Ac , cry2Aa5,
cry1Aa2
H. virescens, M. sexta,
H, armigera
H. zea
Tomato cry1Ac M. sexta
(Gill et al., 2009)
Contd……

23. (a) Bt Cotton
 First generation Bt cotton varieties
• Developed by Monsanto and their seed partners to express the Cry1Ac
protein.
• In USA Bollgard event MON 531 was used to develop the first
commercial Bt cotton varieties for control of Heliothis virescens and
Pectinophora gossypiella.
• Cotton cultivar Coker 312, transformed with the Cry1Ac gene has
shown high levels of resistance to Trichoplusia ni Spodoptera exigua
and cotton bollworms

24. • Stacked with two gene Cry1AC+Cry1AB genes improved level of control
and broaden the spectrum of pest controlled
• Monsanto has created Bollgard II by inserting a gene from B. thuringiensis,
expressing Cry2Ab protein into the Bollgard cotton variety, DP50B, already
expressing Cry1Ac
• It is more effective than Bollgard I in controlling H. armigera, S. exigua, S.
frugiperda
• Monsanto has released Bollgard III in 2015 in Australia which consist
Cry1Ac, Cry2Ab and third protein, Vip3A against Cotton Bollworm
(Helicoverpa armigera) and Native Budworm (Helicoverpa punctigera)
Second generation Transgenic Crops

25. A list of the Bt cotton events approved for cultivation in India

26. Choudhary and Gaur, 2015
Percentage reduction of insecticides on cotton bollworms relative to
total insecticide used in cotton after introduction of Bt cotton

27. Have the yields increased globally due to Bt-cotton?
The yield increases range from 29.0 to 82.0% in the four major countries which
are cultivating Bt-cotton ( Yield in Lakh Bales)
Source: International Cotton Advisory Committee, ICAC, Washington

28. Parameter Before
introduction
of Bt cotton
After the
introduction
of Bt cotton
Per cent
increase/
decrease
Average spray cost
(Rs/ha)
5460 2077 - 61.96
Average seed cotton
yield (q/ha)
15.85 23.95 + 33.82
Average Net profit
(Rs/ha)
7670 10439 +26.52
Dhawan et al., (2011)
ECONOMIC BENEFITS OF Bt COTTON IN PUNJAB

29. Case study
Dhillon and Sharma, 2009

30. Introduction of Bt cotton on 26th March 2002
Beyond doubt, Bt-cotton represents the best of
state-of-art technologies
Genetics is always better than chemicals

31. (b) Bt Maize
 First generation Bt proteins engineered into maize were
Cry1Ab (from B. thuringiensis) and Cry9c (B. thuringiensis subsp.
tolworthi)
• Highly effective against European corn borer, Ostrinia nubilalis
 Dominant Cry1Ab events are:
• Monsanto maize, event MON810
• Syngenta’s BT11 sold as YieldGard and
• Syngenta’s event 176 (Knockout)
 Recently Cry1F intoduced in maize againt rootworm

32. SMARTSTAX MAIZE
• First ever eight-gene, stacked GM variety
• Six Bt toxins genes :
Cry1A.105, Cry2Ab2 (Monsanto), Cry1F (Dow) for insects above
ground
• Cry3Bb1 (Monsanto), Cry34Ab1, Cry35Ab1 (Dow) for insects
underground
• Resistant to certain herbicides:
• Glyphosate (traded as Roundup Ready by Monsanto)
• Glufosinate (traded as Liberty Link by Dow Agro Sciences, under
licence from Bayer)

33. Table: Mean mortality and developmental time of different developmental stages of Spodoptera littoralis when kept on
transgenic maize (Bt+), Bt-sprayed (BtS), and control (Bt–) maize plants
Dutton et al., 2004
Effects of Bt maize expressing Cry1Ab and Bt spray on Spodoptera littoralis

34. (c) Bt Rice
 Various Chinese universities and research institutes in cooperation
with IRRI
 Inserted the Cry1Ab gene alone and a fused Cry1Ab/Cry1Ac into
conventional rice varieties and hybrids
 Scented varieties of rice (Basmati 370 and M7) have been transformed
with Cry2A and are resistant to S. incertulas and C. medinalis.
 In 2009 China has given biosafety approval for developing Bt rice
resistant to yellow stem borer

35. Case study
Transgenic rice expressing the Cry2AX1 gene confers resistance to multiple
lepidopteron pests
• Bt gene, Cry2AX1 was cloned and into rice hybrid JK1044R
• Its effect against two major lepidopteran insect pests viz., yellow stem
borer (YSB) Scirpophaga incertulas, rice leaf folder (RLF)
Cnaphalocrocis medinalis and one minor insect pest, oriental army
worm (OAW) Mythimna separata was demonstrated through
bioassays of transgenic rice plants under laboratory and greenhouse
conditions
Chakraborty et al., 2016

37. (d) Bt Brinjal
 Mahyco in collaboration with TNAU, Coimbatore and UAS, Dharwad developed Bt Brinjal
in India in 2007 by inserting Cry1Ac gene.
 The Cry1Ac gene is driven by a viral promoter, the cauliflower mosaic virus (CaMV) 35S
promoter.
 Bt Brinjal event EE-1 was then introduced into the regular breeding program where it was
back-crossed with seven best performing brinjal hybrids namely MHB-4 Bt, MHB-9 Bt,
MHB-10 Bt, MHB-11 Bt, MHB-39 Bt, MHB-80 Bt and MHBJ-99 Bt
 Against Brinjal shoot and fruit borer Leucinodes arbonalis causing 60-70 per cent losses
 Studies showed a significantly lower number of FSB larvae on Bt brinjal, 0-20 larvae, as
compared to 3.5-80 larvae on the non-Bt brinjal
 India imposed moratorium on Bt Brinjal release on 9th Feb 2010. Bt Brinjal varieties viz., Bt
Uttara, Bt Kajla, Bt Nayantara, and Bt ISD006 cultivated successfully in Bangladesh from
2014.

38. India imposed moratorium on Bt Brinjal
release on 9th Feb 2010

39. (e) Bt Soybean
With respect to the agronomical traits used in GM crops, herbicide and insect resistance, or a
combination of both traits, are the most utilised.
Most of the soybean-planted area is comprised of herbicide-tolerant crops (62%), distributed
across 11 countries.
Until January of 2009, there was no GM soybean that was resistant to insect-pests or pathogens
being commercialised, although the need for this trait is extremely important.
The Bt soybean MON 87701×MON 89788 in the commercial and regulatory pipeline which
efficiently targets a range of species, including Anticarsia gemmatalis (velvetbean caterpillar) and
Chrysodeixis includens (soybean looper) (Bernardi et al., 2012), but it is not efficient against
Spodoptera spp. (armyworms) (Bernardi et al., 2014b).
Today, there is only one commercial GM soybean event from Monsanto, which presents only
herbicide-resistance as a trait.

40. (f) Bt Potato
• A modified Cry3A gene has been expressed in potato plants with
resistance to Colorado potato beetle, Leptinotarsa decemlineata.
(Perlak et al., 1993)
• Transgenic potato plants containing the Cry1Ab gene (Bt884) and a
truncated gene Cry1Ab6,
• Resulted 100% mortality of potato tuber moth, Phthorimaea
operculella in tubers stored up to 6 months
• Marketing of Bt potatoes was stopped in 2001 due to opposition
from several food producers not to use Bt potatoes in their products

41. 2. Plant derived genes
Plant transformation involving plant genes has focused on:
 Protease inhibitor
 Alpha amylase inhibitors
 Lectins
 Chitinases

42. (a) Protease inhibitors
 Insects depends on proteases enzyme like trypsin, chymotrypsin,
and elastase as their primary protein digestive enzymes
 Act as pseudo substrates to enter the active sites of proteases
 Target proteases can not cleave the peptide bonds
 Detrimental disruption of dietary protein in herbivorous pests
 Significant growth and developmental delays

43. (b) Serine protease inhibitor
 First gene of plant origin to be used in transgenic crop protection :
 Transfer of the gene encoding cowpea trypsin inhibitor (CPTi)
 CPTi has been transferred into Nicotiana tabacum and has been
found to impart resistance against Heliothis virescens (Feb.), H.
zea, Spodoptera littoralis (Bois) and Manduca sexta (Johannsen)
 Expression of CpTi in rice enhanced the level of resistance towards
Chilo suppressalis and Sesamia inferens
(Marcherti et al., 2000)

44. Mode of action
 CPTi inhibit essential digestive proteases enzyme
 Resulting in abnormal development and death due to deficiency of
essential amino acids
 Toxicity assays demonstrated that high levels of CPTi are necessary to
obtain insecticidal toxicity but its effectiveness applied to different
species varied approximately 1% of the protein while with Bt
endotoxin, resistance was effective with 0.01 per cent
 Although CPTi inhibits mammalian trypsin, but it is not toxic
mammals
 CPTi is degraded by pepsin in the acidic conditions of stomach before
it encounters the serine protease of the small intestine in the
mammalian gut

45. Examples of Gene stacking using PI
Genes Crop Target insect Reference
Cry1Ac gene from
Bacillus thuringiensis and
CpTi, a trypsin inhibitor
gene from cowpea
Cotton (Gossypium
hirsutum L.)
Helicoverpa
armigera Cui et. al.,
2011
Sporamin (trypsin
inhibitor) from sweet
potato and CeCPI
(phytocystatin) from taro
Tobacco Helicoverpa
armigera
Senthil kumar
et al., 2010
Cystatin Icy6 and Trypsin
inhibitor Itr1, both from
barley
Arabidopsis thaliana Tetranychus
urticae
Santamaria et
al., 2012
Nicotiana alata proteinase
inhibitor (NaPi) and
Solanum tuberosum
potato type I inhibitor
(StPin1A)
Cotton (Gossypium
hirsutum L.)
Helicoverpa
punctigera
Dunse et al.,
2010

46. (c) α-amylase inhibitors
• Interfere with digestion of starch a major energy source particularly
for weevils
• Seeds of bean (Phaseolus vulgaris L.) contain proteins that inhibit the
digestive enzymes of insects
• Since plant protein inhibitors are known to inhibit the growth and
development of larvae Helicoverpa zea (Boddie), Spodoptera exiqua
(Hubber) and colorado potato beetle
• A gene encoding an α-amylase inhibitor from wheat has been
expressed in tobacco, resulting in increased protection against
Spodoptera and Agrotis sp. (Gatehouse and Gatehouse, 1998)

47. Lectins
• Lectins are a group of plant proteins that binds to carbohydrates, including chitin
• All lectins that are toxic to insects exerts their toxicity via binding to specific
carbohydrates substrate
• Snowdrop lectins : The most extensively studied anti-insect lectin is the mannose-
binding lectin from snowdrop (Galanthus nivalis) bulbs. It is generally referred to as
GNA
• Grain aphids (Sitobion avenae) suffered reduced fecundity when they fed on wheat
plants expressing GNA at > 0.04% of total protein but their survivorship was not
affected
(Stoger et al., 1999)
• Transgenic rice expressing GNA protein: Decreased survival (60%) of Nilaparvata
lugens
(Rao et al., 1998)
• IR 64 rice variety transformed with Allium sativum leaf agglutinin (ASAl) conferred
resistance to hoppers
(Saha et al., 2006)

48. Mode of action
• Food recognition by insects depend on sensory receptors commonly located
on the tip of tarsi, antennae and mouthparts
• Binding of lectins to carbohydrate substrate associated with the membranes
of the chemosensory sensillae could block access of food chemical signals to
their actual receptors proteins
• A second potential site of lectin action is the peritrophic matrix (PM), a
protective envelope secreted by the epidermal cells of the midgut and
interfere with digestion
• Ingestion of wheat germ agglutinin (WGA) by European corn borer larvae
Ostrinia nubilalis caused abnormalities.
(Harper et al., 1998)

49. Case Study
Sclerotium rolfsii lectin expressed in tobacco confers protection against
Spodoptera litura
• Study demonstrated the potential toxic effect of Sclerotium rolfsii lectin (SRL)
• The SRL gene was transferred into tobacco plants by Agrobacterium-mediated
transformation
• Bioassays were conducted on second instar S. litura larvae fed on transgenic tobacco
leaves to show larval mortality
• This study was undertaken to demonstrated the acute toxicity of SRL on S. litura
larvae by binding to specific glycoproteins of midgut epithelial cells
Vanti et al.,(2015)

51. Chitinases and other genes
• Chitinase enzymes gene have been transformed into plants and these
show insecticidal properties
• Expression of insect chitinase in transgenic tobacco enhances
resistance to some lepidopterans
(Ding et al., 1998)
• Transgenic potato plants expressing a gene encoding bean chitinase
were found to reduce significantly the size of nymphs in potato aphid ,
Aulacorthum solani
(Gatehouse, 1998)

52. Transgenic crops expressing insecticidal plant genes
Transgenic crop Transgene(s) Origin of transgene Target insect pest
Alfalfa Manduca E-1 Manduca sexta Thrips
Apple CpTi Cowpea Cydia pomonella
Cabbage Modified CpTi Cowpea Pieris rapae
Cotton CpTi Cowpea H.armigera
Maize WGA Wheat Ostrinia nubilalis
Mustard WGA Wheat Lipaphis erysimi
OC-1 Rice Coleoptera
C-2 Soybean Lepidoptera,
Diptera
Pea Alpha-A1 Bean alpha amylase-1 Bruchus pisorum
Zabrotes
subfasciatus

53. Transgenic crop Transgene(s) Origin of transgene Target insect pest
Potato CpTi Cowpea Lacanobia oleracea
GNA Snowdrop L. oleracea, Myzus
persicae,
OC-1 Rice Leptinotarsa
decemlineata
Kti3, C2, PI-4 Soybean Spodoptera
littoralis
Rice CpTi Cowpea Chilo suppressalis
Sesamia inferens
Pot P1-2 Potato C. suppressalis, S.
inferens
GNA Snowdrop Nilaparveta lugens
Nephotettix
virescens

54. Transgenic crop Transgene(s) Origin of transgene Target insect pest
Wheat Cme Barley Sitotroga cerealella
GNA Snowdrop Sitobion avenae
Tomato CpTi Cowpea L.oleracea
GNA Snowdrop L. Oleracea
Pot P1-1, Pot P1-2 Potato H. armigera, T.
commodus
Tobacco CpTi Cowpea H. armigera, H.zea.
M. sexta
SpTi Sweet potato S. litura
Alpha-A1 Bean alpha amylase Agrotis ipsilon
Tom PI -2 Tomato M. Sexta
P-Lec Pea H. virescens
(Brar and Khush, 2001)

55. Insect resistant GM crops in India
Genes: Cry1Aa, Cry1Ab, Cry1Ac, Cry1F, Cry1B, Cry2Ab & Vip-3A
18 prime crops under field testing
Biotic stress resistance (Disease resistance)
Enhancement of quality
Abiotic stress resistance (water, salinity, temperature)
Post Harvest attributes
Edible vaccines
tolerance to pesticides, male sterility
Other traits under development

56. Status of GM crops pending Approval for Field
Trails and Commercial Release in India
Choudhary and Gaur, 2015
Crop Organization Event/Trait Pending
Stauts
Cotton Mahyco/Monsa
nto
cry1Ac and cry2Ab/IR&HT Pending
commercial
approval
Brinjal Mahyco cry1Ac Under
Moratorium
Mustard Delhi University Bar,barnase barstar/AP Final stage
Maize Monsanto cry2Ab2 &cryA.105 and
CP4EPSP/IR&HT
BRL II Stage
Brinjal Bejo
Sheetal/IARI
cry1Abc/IR BRL II Stage
Chickpea Sungrow seeds Bt BRL I Stage
Rice Mahyco NUE BRL I Stage

57. Insect Resistance Against Bt
Unfortunately, the field population of pests evolved resistance to different Bt toxins and
the number of resistant species is going to increase, which is threatening to the
continuous success of Bt crops.
The number of resistant species has been increased worldwide, 13 cases of field-
developed resistance to 5 Bt toxins in transgenic corn and cotton have been reported.
Table: Present status of resistance to Bt plants
Sheikh et al., 2016
Pest Country Gene Crop Year (i) Year (r) Period
Helicoverpa zea USA Cry1Ac Cotton 1996 2002 6 years
Spodoptera frugiperda Puerto Rico Cry1F Maize 2003 2007 4 years
Busseola fusca South Africa Cry1Ab Maize 1998 2004 6 years
Pectinophora gossypiella India Cry1Ac Cotton 2002 2009 7 years
Dibarotica virgifera USA Cry3Bb1 Maize 2010 2013 3 years

58. Resistance mechanisms for Bt
Resist
Resist
Resist
(b) Change
solubilisation
of the toxin
(c) prevent
passage through
the peritrophic
membrane
(e) Prevent
membrane
insertion and
pore formation

59. Trends of resistace developement
Fig: Planting of Bt Crops Globally and Field Evolved Resistance
Tabashnik et al., 2013

60. Tabashnik et al., 2013
Table: Evaluation of Field Evolved Resistance

61. Boll rind, square bracts, ovary & pollen,
have the lowest expression @ 0-1.5 ppm
Pink bollworm feeds more on these parts
Doesn’t Bt-cotton kill pink bollworm ?
Pink boll worm has developed resistance to BG I ( Dhurua and Gujar 2010)
In 2015 pinkboll worm infestation occurred in some pockets of Gujarat,
Maharashtra, Andhra pradesh, Telangana, Karnataka
Low late-season expression reduces the efficacy of Bt-cotton on pink bollworm
slightly.
Reasons for PBW Resistance Against Bt cotton

62. 0
2
4
6
8
10
12
14
16
18
27 40 60 68 75 80 87 96 104 110 116 124 133 138 152 159
Days after sowing
ug/gfreshweight
Top leaf Middle leaf Bottom leaf Square bract Square bud
Cry1Ac expression in Bt-cotton
CICR
• Expression @ 0.002 to 18 ppm
• Boll rind, square bracts, ovary & pollen, have the lowest expression
@ 0-1.5 ppm
• Leaves, square buds & raw cotton seed express @ 0.1 to 18 ppm
•

63. Field-Evolved Resistance of Spodoptera frugiperda to Bt Corn Expressing Cry1F
Table: Toxicity of different Cry toxins to S. frugiperda colonies of SfLab and SfBt.
Monnerat et al., 2015

64. Risks of transgenic crops

65. • Effects of transgenic crops on non target organisms are likely to be
much less severe than broad spectrum insecticides
(Shelton and Bellinder, 2007)
• Shifts in the arthropod community observed in transgenic crops
because of lack of the target pest
(Romies et al., 2006)
• Monarch butterfly caterpillars fed on milkweed plants sprinkled with
Bt maize pollen had reduced growth with higher death rates
(Losey et al., 1999)
1. Effects of transgenics on non target organisms

66. Mean longevity of first instar C. carnea fed with different concentrations of the Cry1Ab toxin dissolved in sucrose
solution
Effect of Bt-consumption on prey utilisation in C. carnea larvae
(Romeis et al., 2014)
Bacillus thuringiensis toxin (Cry1Ab) has no direct effect on larvae of the green lacewing
Chrysoperla carnea (Neuroptera: Chrysopidae)
Food
solution
L1 development
(days±SE)
L1 survival (%) L2
development
(days±SE)
L2 survival (%) L3 dry weight
(µg±SE)
Sucrose 5:1±0:08 84.7 3:4±0:09 96.0 1139±77:8
Bt-sucrose 5:1±0:06 87.9 3:4±0:08 96.1 1252±68:6

67. 2. Gene flow
• Escape of a transgene to its related species or weeds could create
‘super weeds’
• Could be of concern in case of herbicide or insect resistance
• There is no possibility of the native India Desi cotton species
Gossypium arboreum and Gossypium herbaceum species getting
genetically contaminated with GM Bt-cotton
• Desi cottons are diploid in their genetic constitution whereas the
American cotton (G. hirsutum) is allo-tetraploid are incompatible for
cross-fertilization

68. 3. Safety to human health
 Marker genes such as kan-r gene (encodes enzymes providing
resistant to antibiotic kanamycin) used in transformation of plants
 There is a concern that it may be transferred to gut microbes and may
impart bacterial resistance to antibiotics.
(Kaur and Gujar, 2004)
 Cry1Ab and Cry1Ac become inactive in processed corn and
cottonseed meal, but Cry9C is stable when exposed to simulated
gastric digestion and temp. of 900C
 So Bt corn containing Cry9C (Starlink) was not permitted for human
consumption

69. • There are no specific receptors of Bt protein in the gastrointestinal
tract of mammals including humans
• The Bt proteins rapidly degraded by stomach juices in vertebrates
(Sharma et al., 2004)
• The concentrations of Cry proteins in transgenic plants are usually
below 0.1 per cent of total plant protein
• None of the Cry toxins have been demonstrated to be toxic in humans
nor implicated to be allergens
(Shelton et al., 2009)
In contrast……

70. Conclusion
 Global area under transgenic plants has increased 100-fold from 1.7
million hectares in 1996 to over 175 million hectares in 2013 with
majority of Bt transgenics
 In India, Bt cotton is rapidly adopted by farmers as it gives higher
returns and reduces pesticide use
 Transgenic plants have great potential in IPM
 Insect resistance to transgenic crops can be delayed by using strategies
such as refuge crops, high toxin expression etc
 In future, use of gene pyramiding technique for multiple traits

71. Future Thrust
 The huge potential of transgenic technology to enhance crop
production and protection cannot be ignored
 Public sector should release more true breeding varieties so as to
reduce the initial seed cost
 Monitoring and management of insect resistance towards transgenic
crops
 Transgenic crops having tolerance to sucking pests should be
developed

72. THANK YOU