Biotechnology, as you would have learnt from the
previous chapter, essentially deals with industrial scale
production of biopharmaceuticals and biologicals using
genetically modified microbes, fungi, plants and animals.
The applications of biotechnology include therapeutics,
diagnostics, genetically modified crops for agriculture,
processed food, bioremediation, waste treatment, and
energy production. Three critical research areas of
biotechnology are:
(i) Providing the best catalyst in the form of improved
organism usually a microbe or pure enzyme.
(ii) Creating optimal conditions through engineering for
a catalyst to act, and
(iii) Downstream processing technologies to purify the
protein/organic compound.
Let us now learn how human beings have used
biotechnology to improve the quality of human life,
especially in the field of food production and health.
12.1 BIOTECHNOLOGICAL APPLICATIONS IN
AGRICULTURE
Let us take a look at the three options that can be thought
for increasing food production
(i) agro-chemical based agriculture;
CHAPTER 12
BIOTECHNOLOGY AND ITS
APPLICATIONS
12.1 Biotechnological
Applications in
Agriculture
12.2 Biotechnological
Applications in
Medicine
12.3 Transgenic Animals
12.4 Ethical Issues
2022-23
op gh
for increasing food production
(i)
agro-chemical based agriculture;
202
2-2
3
Biotechnology, as you would have learnt from the
pr
evious chapter
, essentially deals with industrial scale
production of biopharmaceuticals and biologicals using
genetically modified microbes, fungi, plants and animals.
The applications of biotechnology include therapeutics,
diagnostics, genetically modified crops for agriculture,
pr
ocessed food, bioremediation, waste treatment, and
energy production. Three critical research areas of
biotechnology are:
(i)
Providing the best catalyst in the form of improved
organism usually a microbe or pure enzyme.
(ii)
Creating optimal conditions through engineering for
a catalyst to act, and
(iii)
Downstream processing technologies to purify the
protein/organic compound.
Let us now learn how human beings have used
biotechnology to improve the quality of human life,
especially in the field of food production and health.
1
2
.
1
B
IO
TE
CH
NO
LO
GI
CA
L
A
PP
LI
CA
TI
ON
S
IN
A
GRICULTURE
A
A
Let us take a look at the three options that can be thought
12.1
Biotechnological
Applications in
Agricultur
e
ur
ur
12.2
Biotechnological
Ap
pl
ications i
n
Medici
ne
12
.3
Transgenic Anima
ls
12.4
Ethical Issues
208
BIOLOGY
(ii) organic agriculture; and
(iii) genetically engineered crop-based agriculture.
The Green Revolution succeeded in tripling the food supply but yet
it was not enough to feed the growing human population. Increased yields
have partly been due to the use of improved crop varieties, but mainly
due to the use of better management practices and use of agrochemicals
(fertilisers and pesticides). However, for farmers in the developing world,
agrochemicals are often too expensive, and further increases in yield with
existing varieties are not possible using conventional breeding. Is there
any alternative path that our understanding of genetics can show so that
farmers may obtain maximum yield from their fields? Is there a way to
minimise the use of fertilisers and chemicals so that their harmful effects
on the environment are reduced? Use of genetically modified crops is a
possible solution.
Plants, bacteria, fungi and animals whose genes have been altered by
manipulation are called Genetically Modified Organisms (GMO). GM
plants have been useful in many ways. Genetic modification has:
(i) made crops more tolerant to abiotic stresses (cold, drought, salt, heat).
(ii) reduced reliance on chemical pesticides (pest-resistant crops).
(iii) helped to reduce post harvest losses.
(iv) increased efficiency of mineral usage by plants (this prevents early
exhaustion of fertility of soil).
(v) enhanced nutritional value of food, e.g., golden rice, i.e., Vitamin ‘A’
enriched rice.
In addition to these uses, GM has been used to create tailor-made
plants to supply alternative resources to industries, in the form of starches,
fuels and pharmaceuticals.
Some of the applications of biotechnology in agriculture that you will
study in detail are the production of pest resistant plants, which could
decrease the amount of pesticide used. Bt toxin is produced by a
bacterium called Bacillus thuringiensis (Bt for short). Bt toxin gene has
been cloned from the bacteria and been expressed in plants to provide
resistance to insects without the need for insecticides; in effect created a
bio-pesticide. Examples are Bt cotton, Bt corn, rice, tomato, potato and
soyabean etc.
Bt Cotton: Some strains of Bacillus thuringiensis produce proteins that
kill certain insects such as lepidopterans (tobacco budworm, armyworm),
coleopterans (beetles) and dipterans (flies, mosquitoes). B. thuringiensis
forms protein crystals during a particular phase of their growth. These
crystals contain a toxic insecticidal protein. Why does this toxin not kill
the Bacillus? Actually, the Bt toxin protein exist as inactive protoxins but
once an insect ingest the inactive toxin, it is converted into an active form
of toxin due to the alkaline pH of the gut which solubilise the crystals.
The activated toxin binds to the surface of midgut epithelial cells and
2022-23
BIOLOG
Y
(ii)
organic agriculture; and
(iii)
genetically engineered crop-based agriculture.
The
Green Revolution
succeeded in tripling the food supply but yet
it was not enough to feed the growing human population. Increased yields
have partly been due to the use of improved crop varieties, but mainly
due to the use of better management practices and use of agrochemicals
(f
er
ti
li
se
rs
a
nd
p
es
ti
ci
de
s)
Ho
we
ve
r
fo
r
fa
r
mers in the developing world,
th
e
at
o
s
a
by
M
.
ly
A’
e
s,
ll
ld
a
s
e
a
nd
at
,
is
e
ll
ut
m
of toxin due to the alkaline pH of the gut which solubilise the crystals.
The activated toxin binds to the surface of midgut epithelial cells and
202
2-2
3
220088
(fertilisers and pesticides). However
, for far
mers in the developing world
,
agrochemicals are often too expensive, and further increases in yield wi
th
existing varieties are not possible using conventional breeding. Is ther
e
any alternative path that our understanding of genetics can show so th
at
farmers may obtain maximum yield from their fields? Is there a way t
o
minimise the use of fertilisers and chemicals so that their harmful effect
s
on the environment are reduced? Use of genetically modified crops is
a
possible solutio
n.
Plants, bacteria, fungi and animals whose genes have been altered
by
mani
pu
lation are called
Genetically Modified Organisms
(
GMO
). G
M
plants have been useful in many ways. Genetic modification has
:
(i)
made crops more tolerant to abiotic stresses (cold, drou
gh
t, salt, heat)
.
(ii)
reduced reliance on chemical pesticides
(p
est-resistant crops).
(iii)
he
lp
ed to reduce post harvest losses.
(iv)
increased efficiency of mineral usage
by
plants (this prevents ear
ly
exhaustion of fertility of soil).
(v)
enhanced nutritional value of food, e.g., golden rice, i.e., Vitamin ‘
A’
enriched rice.
In addition to these use
s,
GM has been used to cr
eate tailo
r
-mad
e
plants to supply alternative resources to industries, in the form of starche
s,
fuels and pharmaceuticals.
Some of the applications of biotechnology in agriculture that you wi
ll
study in detail are the production of pest resistant plants, which cou
ld
decrease the amount of pesticide used. Bt toxin is produced by
a
bacterium called
B
acillus
t
huri
ng
iens
is
(
is
Bt
for short). Bt toxin gene ha
s
been cloned from the bacteria and been expressed in plants to provid
e
resistance to insects without the need for insecticides; in effect created
a
bio-
pe
sticide. Exa
mp
les are Bt cotton, Bt corn, rice, tomato,
po
tato a
nd
soyabean etc.
Bt
C
ot
to
n:
S
om
e
st
ra
in
s
of
Bacillus thuringiensis
produce proteins th
at
is
kill certain insects such as lepidopterans (tobacco budworm, armyworm)
,
coleopterans (beetles) and dipterans (flies, mosquitoes).
B. thuringiens
is
forms protein crystals during a particular phase of their growth. Thes
e
crystals contain a toxic
insecticidal protein
. Why does this toxin not ki
ll
th
e
Ba
ci
ll
us
? Actually, the Bt toxin protein exist as inactive
protoxins
b
ut
s
once an insect ingest the inactive toxin, it is converted into an active for
m
209
BIOTECHNOLOGY AND ITS APPLICATIONS
create pores that cause cell swelling and lysis and eventually cause death
of the insect.
Specific Bt toxin genes were isolated from Bacillus thuringiensis and
incorporated into the several crop plants such as cotton (Figure 12.1).
The choice of genes depends upon the crop and the targeted pest, as
most Bt toxins are insect-group specific. The toxin is coded by a gene
cryIAc named cry. There are a number of them, for example, the proteins
encoded by the genes cryIAc and cryIIAb control the cotton bollworms,
that of cryIAb controls corn borer.
Figure 12.1 Cotton boll: (a) destroyed by bollworms; (b) a fully mature
cotton boll
(b)
(a)
Pest Resistant Plants: Several nematodes parasitise a wide variety of
plants and animals including human beings. A nematode Meloidegyne
incognitia infects the roots of tobacco plants and causes a great reduction
in yield. A novel strategy was adopted to prevent this infestation which
was based on the process of RNA interference (RNAi). RNAi takes place
in all eukaryotic organisms as a method of cellular defense. This method
involves silencing of a specific mRNA due to a complementary dsRNA
molecule that binds to and prevents translation of the mRNA (silencing).
The source of this complementary RNA could be from an infection by
viruses having RNA genomes or mobile genetic elements (transposons)
that replicate via an RNA intermediate.
Using Agrobacterium vectors, nematode-specific genes were
introduced into the host plant (Figure 12.2). The introduction of DNA
was such that it produced both sense and anti-sense RNA in the host
cells. These two RNA’s being complementary to each other formed a double
stranded (dsRNA) that initiated RNAi and thus, silenced the specific mRNA
2022-23
BIO
TEC
HNO
LOG
Y A
ND
ITS
AP
PLI
CAT
ION
S
create pores that cause cell swelling and lysis and eventually cause death
of the insec
t.
Specific Bt toxin genes were isolated fr
om
Bacillus thuri
ng
iensis
and
is
incorporated into the several crop plants such as cotton (Figure 12.1).
The choice of genes depends upon the crop and the targeted pest, as
most Bt toxins are insect-group specific. The toxin is coded by a gene
cells. These two RNA’s being complementary to each other formed a double
stranded
(
dsRN
A)
that initiated RNAi a
nd thus, silenced the specific mRNA
a a
202
2-2
3
220099
gr p sp y ge
cryIAc
named
cry
. There are a number of them, for example, the proteins
encoded by the genes
cryIAc
and
cryIIA
b
control the cotton bollworms,
that of
cryIAb
contr
ols cor
n bor
er
.
Figure 12.1
Cotton boll: (a) destroy
ed
eded
by boll
wo
wo
wo
rm
rm
rm
s;
s;
s;
(
(
(
b)
b)b)
a
a
a
f
ul
ul
ul
ly mature
co
tt
on
b
ol
l
(b
(b
(b
(b
))
(a(a))
Pest
Resistant Plants
:
Several nematodes parasitise a wide variety
of
plants and animals including human beings. A nematode
Meloidegyne
incognitia
infects the roots of tobacco