Biological and Clinical Sciences Research Journal
ISSN:
2708-2261
www.bcsrj.com
DOI:
https://doi.org/10.47264/bcsrj0201009
Biol. Clin.
Sci. Res. J., Volume, 2021: e009
Original Research Article
AGROBACTERIUM-MEDIATED TRANSFORMATION OF COTTON (GOSSYPIUM
HIRSUTUM L.) USING DMO GENE
FOR ENHANCED TOLERANCE AGAINST DICAMBA PESTICIDE
JAVIED MA1, 2*, ASHFAQ N1, HAIDER,
MA1, ALI Q1, ALI A2, MALIK A1
1Institute
of Molecular Biology and Biotechnology, University of Lahore, Lahore, Pakistan
2FB.
Genetics Lab, Four Brothers Group, Lahore, Pakistan
*Corresponding Author email: falakawais7@gmail.com
Abstract
The agrobacterium based transformation of herbicide-resistant
crops has modernized weed management in crops by producing cost-effective and
ecosystem friendly transgenic plants. Cotton is one of the major crops which
are grown worldwide due to its great economic value in textile
industries. Dicamba is a commonly used
herbicide in broadleaf plants to kill a wide range of weeds in many
dicotyledonous crop fields since the 20th century. In this study, Eagle 2
cotton variety was transformed with the DMO gene which is responsible for the
synthesis of the Dicamba monooxygenase
enzyme that exhibits tolerance against the Dicamba
herbicide. This entire study was conducted at Four Brothers Genetics Lab,
Lahore. Transformed cultures of Agrobacterium Tumefaciens with the DMO gene were acquired. Cotton embryos
were isolated and co-cultivated with transformed Agrobacterium
cultures under sterile conditions. Transformed embryos were grown on an
artificial growth medium and acclimatized under favorable conditions. Healthy
and stable plants were shifted infield where they were grown into a mature
plant. Leaf samples of these plants were collected and DNA was successfully
isolated by the CTAB method. Transformed plants were confirmed by Polymerase
chain reaction and gel electrophoresis. Variations in different traits among
transformed cotton plants were found which indicated that the transgenic plant
4 showed higher plant height, monopodial and sympodial branches, leaf length, leaf width, number of
bolls, and bolls weight. The better performance of plant 4 indicated that the
yield potential of the transgenic plant was improved as compared with other
transgenic cotton plants.
Keywords: Gossypium hirsutum, Agrobacterium tumefaciens, Dicamba, genetic engineering, herbicide
Introduction
Gossypium is the genus of
flowering plants that belongs to mallow or Malvaceae
family similar to hibiscus and okra that are natural producer of pure cellulose
fiber known as cotton used in the production of fabric products. Fruit of
Cotton is like a capsule which is called “boll” that contains seeds surrounded
by layers of soft and staple fiber. Cotton plant can grow in both tropical and
subtropical regions. Gossypium is the largest genus of Gossypieae
tribe because it contains 50 species and even more that are yet to be
discovered (Jonathan et al.,
2009). These 50 species are distributed on the basis of their ploidy levels like some of them are diploid (2n=26) and tetraploid (3n=52) (Wendel, 1989;
Wendel and Cronn, 2003).
The word Gossypium is derived from an Arabic word “goz” that
literally means soft substances (Gledhill, 2008). Cotton is a cash crop
majorly produces in Africa, Australia, America, Pakistan, Turkey and India due
its great economical, commercial and industrial importance (Liu et al., 2005; Hari,
2007). Seeds of cotton are also used to feed cattle and poultry animals as
cottonseed meal. It is also used in paper manufacturing as 75% of paper money
is made up of cotton in United States. Income of one billion people depend on
the Production of cotton regardless of technology adopted in the field and in
the factories (Heinicke and Grove, 2005; Humphrey,
2006). Insects attack is one of the major causes for yield loss in the whole
world. Intensive use of herbicides and pesticides in pest management to solve
this problem in past but it also dangerously affects the non-target organisms
in numerous ways. Most common pests of cotton are the species of Lepidopteron
such as fall armyworm (Spodoptera frugiperda), cotton bollworm (Helicoverpa
zea), pink bollworm (Pectinophora
gossypiella), cotton leafworm
(Alabama argillacea), tobacco budworm (Heliothis virescens)
and old-world bollworm (Helicoverpa armigera) (Torres et al., 2009). Environmental pollution and pest resistance against
insecticides are the major problems that are caused by intensive use of these
chemicals that leads towards low profit. Many scientists are working on the
modification of plants to reduce the usage of herbicides and pesticides.
Therefore, the economic and environmental needs support the alternative
strategies to develop the pest resistant cotton crop. Many farmers used genetically
modified plants to increase the yield and enhance the quality of crop worldwide
(Pretty, 2001; Uzogara, 2000; Davies, 2007). In
Agriculture, primary interest is to bring major improvements in agronomic
traits of cotton through conventional methods such as mutation, hybridization
and multiline backcrossing (Awan 1991; Opondo and Ombakho, 1997; Carvalho, 1999; Venkateswarlu and
Corta, 2001; Ahloowalia et al., 2004; Basbag
and Gencer, 2007). Multiple cultivar techniques are
used separately or in combination with other methods such as single lock
descendant, selection of pedigree, cultivar reselection, single lock
descendant, forward crossing and back-crossing (Fehr, 1987; Bowman, 2000; Bayles et al.,
2005).
Above
conventional plant breeding techniques are laborious, time taking and low
efficient (Fehr, 1987). Various genes in the genome of cotton are responsible
for the insect resistant traits (Fehr 1987). Genetic engineering is a
transformation technique in which foreign genes are introduced in the genome of
host plant through transgenesis or sometimes enhance
the expression of already present genes such as genes responsible for salinity
and drought resistance. Genes responsible for undesirable traits are removed
from the genome of plant through the process of gene silencing for instance,
genes exhibits flavor (Kinney, 2003) in soybeans, toxicity secondary compounds
such as gossypol in the seeds of cotton and also injurious to humans (Sunilkumar et al.,
2006). In order to produce transformed varieties capable to tolerate various
environmental stresses such as soil salinity and inadequacy supply of water,
there is need to completely understand the regulatory mechanism of genes
exhibits plant responses to climate changes (Huang and Liu, 2006; Wang et al., 2007). Since the work of Mendelian inheritance in 1866, genetic transformation is
considered as a major progress in the improvement of plant traits. During 21st
century, additional traits are also introduced in plants to enhance the
nutritional content and yield for medicinal purpose.
Genetic
engineering of cotton has tremendously increased the yield and brings the
desired characteristics such as resistance against pests, temperature, salinity
and disease by altering its genome. Fiber quality and yield is improved by
Genetic engineering that further enhance the quality of seed for feed and
edible oil, it also increase the production rate of cotton and reduce the cost.
In 1987, first transformed cotton was developed in USA termed as Bt cotton (Firoozabady et al.1987; Umbeck et al. 1987). Cotton based products can be produced through
transformed cotton which is highly important for economy. Transgenic cotton was
produced via Agrobacterium tumefaciens
based transgenesis (Adang et al., 1989). Major advancements were
made in plant molecular research when A. tumefaciens
were first demonstrated to
generate transgenic plants (Barton et
al., 1983). Transformation in plants allows introduction of foreign DNA in
plants cell as well as plants can be regenerate from already transformed cells.
Genome of various plant species such as petunia, tobacco, sunflower and carrot
were successfully engineered through A. tumefaciens
based transgenesis.
Through wide-spread research,
various procedures were established for A. tumefaciens
mediated transformation of many plant species such as cotton (Umbeck et al.,
1987), sugarbeet (D’Halluin
et al., 1992), maize (Ishida et al., 1996), wheat (Cheng et al., 1997), papaya (Fitch et al., 1993), soybean (Hinchee et al.,
1988) and rice (Hiei et al., 1994). A. tumefaciens transformation is applied by various agronomist all over the world to bring desirable traits in
various monocot species. Although, it is quite challenging while dealing with
the cereal genotypes and further studies are required to bring more advancement
in it. Plant varieties with certain characteristics have been developed
to resist against various herbicides such as glufosinate
and glyphosate tolerance plants in order to produce
low cost varieties with have improved weed management (Ervin et al., 2010; Duke et al., 2008). In addition
of these herbicide tolerant varieties, plant biotechnologist has developed a
new variety exhibit tolerance against Dicamba
herbicide (Behrens et al., 2007). Dicamba is a commonly used herbicide in broadleaf plants to
kill a wide range of weeds in many dicotyledonous crops since the 20th
century. Gene responsible for the synthesis of dicamba
monooxygenase is first isolated from DI-6 strain of a
bacterium Pseudomonas maltophilia
specialized in the degradation of Dicamba. Dicamba resistant gene is altered through genetic
engineering to express in broadleaf crops and provide tolerance against many
times higher concentration of Dicamba than the
recommended concentration that is used as herbicide in various plants (Behrens et al., 2007). Genetically engineered
cotton and soybean plants having Dicamba resistant
gene are in last phases of development and will be available in market soon.
Dicamba resistant
varieties of cotton plant will offer wide range of significant characteristics
such as broadleaf weeds management as well as ability of fight with weeds
resistant to various herbicides and hence, combat against the various new types
of herbicide resistant weeds (Behrens et
al., 2007; Service et al., 2007).
Dicamba resistant gene is responsible for the
synthesis of a vital enzyme Dicamba monooxygenase also known as DMO (Herman et al., 2005) is isolated from the DI-6
strain of a bacterium Pseudomonas maltophilia (Krueger et al., 1989).The function of this enzyme is the elimination of an
O-methyl group present in the aromatic ring of the Dicamba
herbicide. Its function requires the activity of two other enzymes ferredoxin and reductase along
with a reducing agent NADH (Chakraborty et al., 2005). Earlier studies suggested
that the activity of these other enzymes are not required for the DMO based
degradation of Dicamba when targeting the chloroplast
of transgenic broadleaf plants such as cotton due to the presence of
chloroplast ferredoxin isolated from P. maltophilia.
Material and methods
These
studies were conducted in Four Brothers Genetics Laboratory, Lahore. The DMO
gene cassette was designed by Dr. Arfan Ali from Four
Brothers Genetics Lab and the research work were performed there.
Preparation of electro-competent Agrobacterium cells
LBA4404 strain of Agrobacterium tumefaciens
bacterium was cultured on
petri plates contains YEP media and isolated complex
colonies were appeared. Single colony was collected with the help of sterilized
tooth pick and inoculated into 5ml of YEP broth and 100µg/ml concentration of rifampicin was used for the selective growth of desire Agrobacterium cells. After that culture were placed on incubation at
28˚C for 2 days. Grown culture was transferred to 100ml of YEP broth.
Culture was reserved on orbital shaker at 28˚C at 300 rpm for 48 hours
incubation. Furthermore, culture was incubated on ice for 15 min and
transferred into 50ml sterilized falcon tube. Cells were collected after 15
minutes centrifugation at 4˚C. Then, supernatant was removed from the
solution. After that washed the pellet for two times with
40ml of HEPES solution. Re-suspend the pellet in 1.0ml glycerol
solution. Make the aliquots of 80µl as a stock solution then stored at -70ºC in
ULT freezer.
Confirmation of
transformed Colonies
Whole
work was conducted in laminar flow cabinet where YEP cultured cells were set in
shaking incubator at 28°C for 60 minutes. Cultures were mixed well by shaking.
Then, 100µl of cultured YEP were taken and spread on YEP plates with kanamycin selection. Sterilized spreader was used to spread
the whole culture on media. These plates were Kept incubated on 28°C for 48
hours. Colonies were confirmed after incubation.
Colony PCR
Colony
PCR was used to confirm the colonies of transformed cells where 3ml of
bacterial culture of YEP were taken in a sterilized falcon tube. After that,
100µl of bacterial culture were taken in an Eppendorf
tubes. Culture was placed on Centrifuge machine for 10 minutes centrifugation.
Supernatant of the centrifuged solution was discarded and pellet was dissolved
by 50ul of TE buffer. When the pellet was completely dissolved, then mixture
was shifted into PCR tubes. Dissolved solutions were placed on PCR at
98◦C for 12 minutes incubation. After incubation, PCR tubes were placed
on short spin for 10 minutes and Template was ready to use in colony PCR. 4ul
of supernatant was picked and transferred to another PCR tubes. The master mix
was prepared for colony PCR in which mgcl2, buffer, dNTPs, forward primer, reverse primer, taq
polymerase and water was added.
Confirmation of DMO gene into Agrobacterium
Construct
of DMO gene transformation into Agrobacterium competent cells was confirmed when
colony PCR was applied as confirmation step of transformation. Primers were
designed related to gene construct. Amplify the product at 501 bp region. PCR product was determined at 1% agarose gel electrophoresis for 30 minutes at 120 volts.
Predict the bands under UV light.
Preparation of
Glycerol stock
Positive
clones of PCR were inoculated into YEP broth of 50 ml falcon tubes. The
cultures were incubated at 28ºC for 24 hours. They were used as a glycerol
stock solution by the addition of 250µl glycerol and 750 µl of bacterial
culture was also added in Eppendorf tubes. Glycerol
stock was prepared and preserved at -70ºC for future use.
Preparation of competent cells
Secondary
culture were prepared from first culture after 48 hours incubation and then,
further incubated for 7-8 hours. When incubation was successfully performed the
culture tubes were kept on ice for further preservation. The cells were
accumulated by centrifugation at 13500 rpm at 4ºC for 10 minutes. Discard the
supernatant solution and dissolved the pellet by using 1ml of 0.1M CaCl2.
Solution was centrifuged again. Pellet was re-suspended by 100µl of CaCl2.
Competent cells ready to use.
Selection of seed variety
Seeds of cotton
variety Eagle-2 were obtained from Four Brothers biotechnology and genetics
Lab. Seeds were delivered to lab and removed the lint by sulphuric
acid (H2SO4).
De
linting of Seeds
De linting is a process used to
completely eliminate fuzz from seed coat in cotton seed. It’s a management
technique for crop specific seed. Efficient variety of seeds was taken with
high germination rate. 100ml/Kg is a concentration of sulphuric
acid (H2SO4). When seeds were poured in a beaker 20ml of
acid was added and (80ml distilled water). Whole solution was mixed by
continuously stirring of spatula for 7-10 times until the lint was removed.
Wash the seeds for 5-7 times with tape water to completely remove the residue
of acid. Some of the seed was floated and some seeds sink. Only sinker seed was
selected for further processing. This process associate the variety Eagle-2 of
cotton was selected for transformation.
Screening
of Seeds
Process involved screening of seeds. This process is
beneficial for decontamination of seed. Damaged seed were removed. Dirt and
other trash must be removed. Healthy and disease free cotton seed was taken.
Soaking
of Seeds
25g of Eagle-2 variety of cotton seed was taken in a
sterilized autoclaved 1L conical flask and autoclaved water was used for
soaking of seeds. The seed were sterilized by adding 1ml of 10% SDS and 2ml of
5% HgCl2. The seeds were steeped by putting 100ml of distilled
autoclaved water. Shake it gently until the SDS is completely removed from
seeds. Desirable amount of water was removed. Aluminium
foil was used to cover the mouth of flask. Overall flask was covered by paper
and incubated at 30˚C for overnight incubation. Next day wash the seed
with 2ml of 5% HgCl2.Shake it gently, until all HgCl2 was
removed from seeds. Again covered the flask by paper and overnight incubated at
30˚C. Next day germinated embryos were observed.
Isolation of Seed Embryo
After
48 hours incubation, germinated seeds were grown in flask. With the help of
scalpel and forceps the seat coat was removed.
Deal the embryo slightly with the help of forceps and pressed the testa of seed with the support of scalpel. Gently embryo
was isolated from seed coat. Surgical blade was used for light cut of embryo.
Mature embryo of germinating seeds was taken. All healthy embryos were kept in
bacterial culture while damaged embryos were discarded.
Co-Cultivation of Agrobacterium Inoculum
After
embryo isolation, the culture of DMO
was taken and centrifuged the culture for 5 min at 4˚C at 5000 rpm.
Supernatant solution was discarded. Then, dissolve the pellet in 10ml of broth.
Further the isolated embryos were transferred to the Agrobacterium explants after
placing a cut on them. Embryos were kept on orbital shaker at 28ºC for half an
hour.
Preparation of MS medium
MS
media was prepared and autoclaved. Cool the media at 50ºC. Cefotaxime
(250µg/ml) was added into media. 15ml tubes were taken and 10ml of YEP broth
was added that possess 50µg/ml kanamycin for
selection. Further addition of glycerol
stock of 10µl for Agrobacterium retained the DMO gene construct. Tubes were kept in culture room.
Shifting of
embryos in plates
After
co-cultivation, embryos were dried on sterilized filter paper and transferred
on MS media plates with the help of forceps. Kept the plate at room temperature
for suitable growth conditions where embryos were incubated and grew well.
Plantlets shifting in tubes
Plantlets
were produced after 3 days (72h) of co-cultivation. The plantlets that present
in plate of MS were taken. The plantlets were shifted in tubes by the selection
of kanamycin (500µl) and ceftriaxone
(250µl) drug. Standard plantlets were preserved on MS medium. After that, the
tubes were covered with pre-sterilized cotton plugs and kept the tubes on plant
growth room at suitable conditions.
Time
period of 2 months were required for its growth in tubes.
Shifting of plants into pots and
acclimatized
Plantlets
were mature after 8-10 weeks in tubes, and were shifted into pots containing
sterilized autoclaved soil. Fungicide was added in soil to prevent the growth
of fungus. MS media was removed from roots by washing with water and dried with
tissue paper. The Growth hormone such as
indole-3-butyric acid (IBA) was added in roots for better growth of transgenic
cotton plants. Plants were covered by plastic bags. To maintain the photoperiod
time 16h light and 8h dark, kept the plants at room temperature at 25±2°C. Plants were acclimatized at this stage.
Plants shifting into field
Transgenic
cotton plants that were shifted into pots from tubes were acclimated. Plastic
bag is removed for 15min interval of light and then time period increases15min
onward on daily basis for one month.
Plants were daily watered and opened at 10:00 AM onward for 4 weeks. During
1st week plants showed minimal droop due to dehydration, this was
retrieved by passing of time. However, the loss of 5% transgenic cotton plants
was detected for DMO gene after 10-15
days. The healthy plants were acclimated and stabilized were shifted to field (Behria farm) of four bothers.
DNA Extraction
Transgenic
cotton plant
with DMO gene was examined through
molecular analysis. DNA extraction from plants
sample can be done by young germinated leaves of the plants that were sited
into liquid nitrogen and grinded into a fine
powder. The powder was transferred into Eppendorf tubes
and 500µl of extraction buffer was added. 400µl of CTAB was added. 10µl of β mercaptoethanol was added. Vortex the Eppendorf tubes thoroughly. Incubated Eppendorf
tubes in a water bath at 65°C for 90
minutes. After that, 500µl of equal volume of chloroforlm:isoamylalcohol (24:1) were added. Centrifuged the
solution at 13500 rpm for 15 min. 500µl supernatant solution was taken, and the
pellet was discarded. Repeated the above step until solution is not clear.
Again 500µl of supernatant was taken and transferred to a new Eppendorf. 60% of chilled isopropanol
was added. Kept the Eppendorf tubes
at -20°C for overnight incubation until DNA was clustered. Next day,
centrifuged the sample and harvested pellet. Discarded the supernatant
solution, pellet was remained in Eppendorf tube. 1ml
of washing solution with (70% ethanol) was added to wash the DNA pellet. Again Centrifuged the DNA pellet for 10 min at 13500 rpm.
The supernatant solution was discarded, air dried the
pellet for 1hour at room temperature. Eluted the DNA pellet
with 15µl of nuclease free water. 7µl of Rnase
was added. Kept the genomic DNA Eppendorf tubes on
water bath at 37°C for 30 minutes to
determine the genomic DNA extraction of transgenic cotton plant used agarose gel electrophoresis.
Gel Electrophoresis
Gel
electrophoresis is used for analysis of the DNA molecules. It separated the
fragments of genomic DNA according to their size and charge, consisted of one
glass caster plate and comb which form wells in the gel used to load DNA
samples. DNA is a negatively charge, and the movement of charge occurs towards
the positive electrode due to electric current.
1%
concentrated gel was prepared by adding 200ml of 1x buffer into 1.6g of agarose in a gar. Heat the solution mixture at oven for 2-3
minutes. After that, kept the solution mixture at room
temperature for 5 minutes. 5µl of Ethidium
bromide was added. Gel was cast into a caster plate.
Gel Documentation
After
electrophoresis, samples are absorb in gel medium and photographed in
ultraviolet light (254nm) with a red filter on the camera. Its ultraviolet
light shows the fragments (bands) of genomic DNA.
Polymerase Chain Reaction (PCR) of
transgenic cotton plant
PCR
(polymerase chain reaction) was used to determine the DMO gene in cotton plants. Assembled the mixture with 2µl of DNA, 10x PCR buffer(2ml), 2.5mM Mgcl2 (2.5)
1mM dNtps (2ml) one picomole
each primer (2ml) and 2.5µl taq DNA polymerase for a total volume of 20 ml was prepared
with gene specific primer. The process were performed thermocycler
PCR machine depends on following conditions, initial denaturation
at 95oC for 3 min, then further denaturation
at 95oC for 30 sec of 35 cycles, annealing at 60oC for 45
sec for DMO gene, followed by extension at 72oC for 10 min.
amplification were completed then products was determined by 1% agarose gel and visualized under UV light.
Figure 1: Temperature conditions of PCR for DMO gene
Results
4.1
Transformation and confirmation of DMO gene construct
DMO-gene construct
was positively transformed into Agrobacterium tumefaciens and colonies were used to determine of gene
through colony PCR. PCR amplification of 501 bp
was done by using primers. PCR resolute the existence of DMO gene construct in Agrobacterium. PCR products were resolved on 1% agarose gel.
DNA ladder of 1 kb plus was used to determine the size of amplified fragments.
Positive colonies were formed after 48 hours grown culture as a glycerol
stock. Glycerol stocks were preserved at -70°C. Positive clones are used for
embryonic transformation.
Figure 1:
Transformed Isolated colonies
Fuzzy seeds
Fuzzy
seeds were covered with lint and it was removed through sulphuric
acid concentration. Continuously stirring with spatula was used to completely
remove lint from seeds.
Fuzzy seeds De lint
seeds
Figure 2: De linting of Seeds
Germinated
soaked seeds
After
48 hours incubation, the flask having germinated sterilized soaked seeds as
embryos germinated. The white embryonic roots were appeared from seed coat.
Figure 3:
Germinated soaked seeds
Co-cultivation
Isolated embryos
After
germination, embryos were isolated and co-cultivated in a culture medium. Then, kept the culture at orbital shaker at 28°C for half an hour.
Embryos were washed with MS media until solution was not clear. Embryos were
dried on filter paper to transform on MS plates.
Figure 4:
Embryos isolation
Figure 5:
Co-cultivation of Embryos
Transformation
of embryos on MS medium plates
After the
co-cultivation of embryos. They were transferred to MS medium
plates for the growth of plantlets at specific growth conditions for 3 days.
Three days stages are following:
Figure 6.1: 1st
Stage of embryo transformation on MS plates
Figure 6.2:
2nd stage of embryo transformation
Figure 6.3: 3rd stage of embryo transformation
Transformation
of cotton along with Eagle-2 variety and shifted to MS tubes
Transformation
of Gossypium hirsutum var.
Eagle-2 was completed through trials. Full grown embryos were taken as a source
of xplants and were shifted into MS medium of tubes. Total
10,000 embryos were deal with the DMO construct. Out of 10,000 embryos only 85
plants were persist of following 2 months of time period with the selection of
drug as kanamycin hold within MS media tubes. Only 1%
transformation efficiency was conducted by the selection of kanamycin.
Embryo isolation and incubation was performed according to materials and
methods. Different stages were performed and Agrobacterium treated show one by
one stage of incubation in plates and tubes already mentioned in material and
methods. The results indicated that 85 embryos were treated well with selection
on MS medium tubes.
Figure 7: Transformed plantlets shifting
in test tube of MS media
Figure 7.1: 1st
Stage of Plants growth in tubes
Figure 7.2: 2nd
Stage of Plants growth in tubes
Figure 7.3: 3rd
Stage of Plants growth in tubes
Shifting of plants to soil pots
After 7-8 weeks plantlets were mostly
grown on MS medium tubes. The result show that these plantlets were further
transferred to soil pots.
Figure
8: plants shifting in soil pots
Plants shifted
to field
Plants
were developed in pots than at this stage were shifted to field. Herbicides
spray was applicable to resist the plants. Some plants were remained after
field conditions and gave high amount of productivity. Some were dying at this
stage and showing the negative effects for DMO
gene.
Molecular
analysis of Transgenic cotton Plant
DMO
confirmed through PCR
DNA extraction of 50 plants were done stated to procedure. PCR
was performed regards to DMO. PCR
product size (501 bp) were amplified by 1 kb plus DNA
ladder and resolved on 1% agarose gel. Results
indicated that 9 plants
out of 21 were
shown the positive effect for DMO.
Figure 9 Lane 1:
1Kb ladder, lane 2: negative control, lane 3: positive control, lane 4, 5, 6,
7and 8: positive transformation of DMO gene (PCR product size is 501 bp) and lane 9, 10: negative transformation
Table
1. Analysis of
transgenic cotton plants
Plant no. |
Height (cm) |
Leaf length (cm) |
Leaf width (cm) |
No. of bolls |
Bolls weight (g) |
Monopodial branches |
Sympodial branches |
Control
|
69 |
9.5 |
6.4 |
31 |
5.6 |
8 |
23 |
Plant
1 |
56 |
9.6 |
6.2 |
12 |
5.8 |
7 |
15 |
Plant
2 |
54 |
9 |
5.1 |
13 |
4.4 |
8 |
8 |
Plant
3 |
63 |
9.1 |
5.3 |
22 |
5.6 |
6 |
20 |
Plant
4 |
68 |
10.4 |
6.9 |
39 |
6.2 |
13 |
34 |
Plant
5 |
63 |
8.7 |
5 |
32 |
6 |
5 |
20 |
Plant
6 |
54 |
9.2 |
4.9 |
34 |
5.4 |
9 |
34 |
Plant
7 |
39 |
7.8 |
5.8 |
18 |
4.8
|
10 |
29 |
Plant
8 |
46 |
8.1 |
5.3 |
31 |
5.1 |
13 |
27 |
Plant
9 |
64 |
10.3 |
5.7 |
18 |
4
|
8 |
20 |
The plant height was found higher for
plant 4 (68cm) while lowest of plant 7 (39cm), leaf length was found higher for
plant 4 (10.4cm) while lowest for plant 7 (7.8cm), leaf width was higher for
(6.9cm) while lower for plant 2 (5.1cm). The higher number of bolls was found
for plant 4 (39) while lower for plant 1 (12), the higher boll weight was for
plant 4 (6.2g) while lower for plant 9 (4g), the higher number of monopodial and sympodial branches
were for plant 4 (13) and (34) respectively while lower monopodial
branches were for plant 5 (5) while lower sympodial
branches were found for plant 2 (8).
Discussion
Pakistan’s
major cash-cow crop is maize, sugarcane, wheat and cotton. Farmers earn their
living by selling these crops. Cotton is responsible for providing 80% of raw
material to the industries. This crop plant offers maximum yield. The main hindrance
in cotton production is viruses, insects, weeds and pests. Weed is responsible
for 25% loss of the cotton crop whereas insects are responsible for 20% loss
(Liu et al., (2005). In our recent
research, an attempt on Agrobacterium
mediated transformation method was
done to alter DMO gene in cotton. The
main goal was not only to transform cotton but also to increase the
transformation efficiency and to provide maximum yield. Cotton cultivators
found effectiveness in transformation at optimized conditions reliant upon
genotype. In order to withstand severe environmental conditions; healthy seed
embryo was taken. Related transformation efficiency was observed by Puspito et al.,
(2015) Strengthening of 501 bp product through colony
PCR for DMO was clarified the productive transformation in cotton plant. Hence,
the results proved that the cotton production can be improved by inserting DMO
in cotton.
In our current research, by Agrobacterium tumefaciens
Eagle-2 variety was used for transformation in cotton. Eagle-2 variety of
cotton was screened because it is capable to germinate and form mature embryos.
The germinated embryos of Eagle-2 variety of cotton were placed in culture
medium for co-cultivation for half an hour at shaking incubation at 28◦C.
it is compulsory to cut the embryo with the help of scalpel then these embryos
are transferred on plates of MS medium. This is done before placing it in
culture medium (Davies, 2007; Hari, 2007). After 48
hour plantlets produced on MS medium plates, these plantlets were further
transferred to MS medium tubes already having selection of drugs. The results
obtained from this showed that some plants survived of MS medium tubes and some
died at this stage after 3-4 weeks. Hence, those plants that died could not
produce roots on tubes medium. While some of the other plants that survived
developed roots and grew well on MS medium after 3-4 weeks. The plants that
grew from Eagle-2 variety of cotton were then shifted to soil pots and adapted
at growth room at optimum conditions. Some plants that survived were then ready
to shift in the field. For the genetic transformation of cotton, we were able
to obtain 20 plants from 1000 embryos. After that DNA extraction was performed.
After this transformation 9 plants were positive for DMO gene and the other remaining 9 showed the negative control for
amplification of product 501 bp through colony PCR.
After all these processes, the Eagle-2 variety of cotton showed best results (Ahloowalia et al.,
2004; Jonathan et al., 2009).
Therefore, Eagle-2 variety was selected for transformation in cotton via Agrobacterium tumefaciens. In
field condition plants showed variation in different traits among transformed
cotton plants were found which indicated that the transgenic plant 4 showed
higher plant height, monopodial and sympodial branches, leaf length, leaf width, number of bolls
and bolls weight. The better performance of plant 4 indicated that the yield
potential of transgenic plant was improved as compared with other transgenic
cotton plants.
Conclusion
Genetic Engineering is breading strategy
that allows the number of foreign genes (from any source) at a time to be
introduced into a plant. Cotton is grown in all parts of the world. The main
reason is that it is a good source of economy. It has a good economic ratio and
it is also widely used at industrial scale for the manufacturing of household
materials and clothing apparel. Due to selective breeding, commercially available
cotton have white colour. White cotton is further
dyed into different colors with the help of fabric dyes for the manufacturing
of clothes. The conducted study was evaluated to examine the positive influence
of DMO gene on transgenic cotton
plant. The samples were collected at Four Brothers Genetics Lab. The DMO gene has good potential to come over
the problems which are being caused by insects and weeds. The embryos isolation
and co-cultivation was conducted in lab under sterile conditions. And hence the
plants obtained from following transformation method were then transferred in
acclimatized room and adapted on growth room at optimum conditions, and after
that shifted to field growth conditions. DNA extraction was carried out using
CTAB method on fresh leaves of 21 plants of transgenic cotton which were
obtained from the field. PCR was conducted on these plants to confirm the
positive influence and successful integration of DMO gene in cotton. After PCR
confirmation, some variations were observed in parameters like some plants have
high height rate than others. Therefore, leaf height, leaf width, leaf length,
Number of bolls per plants, weight of each bolls, bolls of each plant, sympodial branches and Monopodial
branches were took into consideration and compared to other plants.
References
Adang, M., DeBoer, D., Endres, J., Firoozabady, E., Klein, J., Merlo, D.,
... & Stock, C. (1989). In Biotechnology, Biological Pesticides and
Novel Plant-Pest Resistance for Insect Test Management; Roberts, DW; Granados,
RR, Eds. Insect Pathology Resource Center, Boyce Thompson Institute for
Plant Research at Cornell University, Ithaca, NY, 31-37.
Ahloowalia B.S., Maluszynski M., Nichterlein K.
(2004) Global impact of mutation-derived varieties. Euphytica 135, 187–204
Awan
M.A. (1991) Use of induced mutations for crop improvement in Pakistan, p.
67–72.
In International Atomic Energy Agency (Ed.), Plant Mutation
Breeding for crop improvement, Viena, IAEA, 554p.
ISBN 92-0-010091-0.
Barton,
K.A., Binns, A.N., Matzke,
A.J., Chilton, M.D. (1983) Regeneration of intact tobacco plants containing
full length copies of genetically engineered T-DNA, and transmission of T-DNA
to R1 progeny. Cell 32: 1033-1043
Basbag S., Gencer O. (2007) Investigation of some yield and fibre quality characteristics of interspecific
hybrid (Gossypium hirsutum
L.×G. barbadense L.)
cotton varieties. Hereditas 144, 33–42.
Bayles, M.B., Verhalen, L.M., McCall, L.L., Johnson, W.M., Barnes, B.R.
(2005) Recovery of recurrent parent traits when backcrossing in cotton. Crop Science 45, 2087–2095.
Behrens,
M.R., Mutlu, N., Chakraborty,
S., Dumitru, R., Jiang, W.Z., Lavallee,
B.J., Herman, P.L., Clemente, T.E., Weeks, D.P. (2007)Dicamba tolerance: enlarging and preserving
biotechnology-based weed management strategies. Science 316, 1185–1188.
Bowman,
D.T. (2000) Attributes of public and private cotton
breeding programs. Journal of Cotton Science 4, 130–136.
Carvalho, L.P. (1999) Contribuic¸ ˜ao do melhoramento ao cultivo do algod˜ao no Brasil, p. 253–269. In Beltr˜ao
N.E.M. (Ed.), Agroneg´ocio do algod˜ao
no Brasil. v.1. Embrapa Comunicac¸ ˜ao para Transferˆencia
de Tecnologia, Bras´ılia.
ISBN 85-7383-060-3.
Cheng, M., Fry, J.E., Pang, S., Zhou, H., Hironaka, C.M., Duncan, D.R., Conner, T.W., Wan, Y. (1997)
Genetic transformation of wheat mediated by Agrobacterium
tumefaciens. Plant Physiology 115:
971-980
D’Halluin,
K., Bossut, M., Bonne, E., Mazur, B., Leemans, J., Botterman, J. (1992)
Trans-formation of sugarbeet (Beta vulgaris L.) and evaluation of herbicide resistance in
transgenic plants.
Bio/Technology 10: 309 – 314
Davies
K.M (2007). Genetic modification of plant metabolism for
human health benefits. Mutat Res-Fund Mol M
622: 122-137.
Duke,
S.O., Powles, S.B. (2008). Glyphosate:
a once in a century herbicide. Pest
Management Science 64, 319–325.
Ervin, D.E., Carriere, Y.,
Cox, W.J., Fernandez-Cornejo, J., Jussaume,
R.A.A., Jr., Marra, M.C., Owen, M.D.K., Raven, P.H., Wolfenbarger, L.L., Zilberman, D.
(2010).
Impact of Genetically Engineered Crops on Farm Sustainability in the United
States; The National Academies Press: Washington, DC.
Fehr,
W.R. (1987) Principles of cultivar development: theory and technique, vol. 1.
McGraw-Hill, New York. ISBN 0070203458.
Firoozabady,
E., Deboer, D.L., Merlo, D.J., Halk,
E.L., Amerson, L.N., Rashka,
K.E., Murrae, E.E. (1987) Transformation of cotton (Gossypium hirsutum L.)
by Agrobacterium tumefaciens
and regeneration of transgenic plants. Plant Molecular Biology 10,
105–116.
Fitch,
M.M.M., Manshardt, R.M., Gonsalves,
D., Slightom, J.L. (1993) Transgenic
papaya plants from Agrobacterium-mediated
transformation of somatic embryos. Plant
Cell Reproduction 12: 245-249
Gledhill,
D. (2008). The
Names of Plants (4
ed.). Cambridge University Press.
p. 182. ISBN 978-0-521-86645-3.
Hari, G. (2007). Multiple references to non-wood fibers for paper. Paper on Web, Pulp & Paper Resources & Information Site.
Heinicke, C., Grove W.A.
(2005) Labor markets, regional diversity, and cotton harvest mechanization in
the post-World War II United States. Social Sci. Hist. 29, 269–297.
Herman, P.L., Behrens, M., Chakraborty,
S., Chrastil, B. M., Barycki,
J., Weeks, D.P. (2005). A three-component Dicamba O-demethylase from
Pseudomonas maltophilia, strain DI-6: gene isolation,
characterization and heterologous expression. Journal of Biological Chemistry 280, 24759–24767.
Hiei, Y., Ohta, S., Komari, T., Kumashiro, T. (1994) Efficient transformation of rice (Oryza sativa L.) mediated by Agrobacterium and sequence analysis of the
boundaries of the T-DNA. Plant Journal 6:
271-282
Hinchee, M.A.W.,
Connor-Ward, D.V., Newell, C.A., McDonnell, R.E., Sato, S.J., Gasser, C.S., Fischhoff, D.A., Re, D.B., Fraley, R.T., Horsch, R.B. (1988) Production of transgenic soybean plants
using Agrobacterium-mediated DNA transfer. Bio/Technology
6: 915-922
Huang,
B., Liu, J.Y. (2006) A cotton dehydration responsive
element binding protein function as a transcriptional repressor of DRE-mediated
gene expression. Biochemical and
Biophysical Research Communications 343,
1023–1031.
Humphrey, J. (2006) Commodities, diversification and
poverty reduction, p. 380–401. In Sarris A., Hallam
D. (Eds.), Agricultural commodity markets and trade: new approaches to
analyzing market structure and instability. FAO-ONU, Roma,
Italy. ISBN 1-84542-441.
Ishida,
Y., Saito, H., Ohta, S., Hiei,
Y., Komari, T., Kumashiro,
T. (1996) High efficiency transformation of maize (Zea
mays L.) mediated by Agrobacterium
tumefaciens. Nat
Biotechnology 14: 745-750
Jonathan,
F., Wendel, Curt, Brubaker, Ines.,
Alvarez, Richard C. and James McD. Stewart. 2009.
Evolution and Natural History of the Cotton Genus. In Andrew
H. Paterson (Ed.). Genetics and Genomics of Cotton.
Plant Genetics and Genomics: Crops and
Models 3, 3–22.
Kinney,
A.J. (2003). Engineering soybeans for food and health.
AgBioForum 6, 18–22.
Krueger,
J.P., Butz, R.G., Atallah,
Y.H., Cork, D.J. (1989). Isolation and identification of microrganisms for the degradation of dicamba.
Journal of Agricultural Food Chemistry
37, 534–538.
Liu,
J., Yang, H., Hsieh, Y.L. (2005). Distribution of Single
Fiber Tensile Properties of Four Cotton Genotypes. Text Research Journal 75: 117-122.
Opondo, R.M., Ombakho, G.A. (1997) Yield evaluation and stability
analysis in newly selected “KSA” cotton cultivars in western Kenya. African Crop Science Journal 5, 119–125.
Puspito, A.N., Rao, A.Q., Hafeez, M.N., Iqbal, M.S., Bajwa, K.S., Ali,
Q., Rashid, B., Abbas, M.A., Latif,
A., Shahid, A.A. and Nasir,
I.A., 2015. Transformation and evaluation of Cry1Ac+ Cry2A
and GTGene in Gossypium hirsutum L. Frontiers
in Plant Science, 6, p.943.
Pretty, J. (2001). The rapid
emergence of genetic modification in world agriculture: contested risks and
benefits. Environmental Conserv 28: 248-262.
Service,
R.F. (2007). A growing treat down on the farm. Science 316, 1115–1117.
Sunilkumar G., Campbell
L.M., Puckhaber L., Stipanovic
R.D., Rathore K.S. (2006) Engineering cottonseed for
use in human nutrition by tissue-specific reduction of toxic gossypol. Proceeding of National Academy
of Science USA 103, 18054–18059.
Torres, J. B., Ruberson,
J. R., & Whitehouse, M. (2009). Transgenic cotton for sustainable pest
management: a review. In Organic Farming, Pest
Control and Remediation of Soil Pollutants (pp. 15-53). Springer, Dordrecht.
Umbeck, P., Johnson, G.,
Barton, K.., Swain, W. (1987) Genetically transformed
cotton (Gossypium Hirsutum
L.) plants. Bio/Technology 5:
263-266
Uzogara SG (2000).The
impact of genetic modification of human foods in the 21st century: A review. Biotechnological Advances 18: 179-206.
Venkateswarlu, D., Corta, L. (2001). Transformations in age
and gender of unfree workers on hybrid cottonseed
farms in Andhra Pradesh. Journal
of Peasant Studies 28, 1–36.
Wang,
M.M., Zhang, Y., Wang, J., Wu, X.L., Guo, X.O. (2007)
A novel MAP kinase gene in cotton (Gossypium hirsutum L.), GhMAPK, is involved in response to diverse environmental
stresses. Journal of Biochemical and Molecular Biology
40, 325–332.
Wendel, J.F., Cronn, R.C. (2003). Polyploidy and the
evolutionary history of cotton. Advanced Agronomy 78: 139-186.
Wendel, J. F. (1989).
New World tetraploid cottons contain Old World cytoplasm. Proceedings
of the National Academy of Sciences, 86(11), 4132-4136.