Plant biotechnology can be defined as the use of tissue culture and genetic engineering techniques to produce genetically modified plants that exhibit new or improved desirable characteristics. PLANT BIOTECHNOLOGY HELPS PLANT PATHOLOGY IN MANY WAYS.

1. BIOTECHNOLOGY IN FUNGAL AND
BACTERIAL DISEASE MANAGEMENT
Submitted by:
K Sarda Devi
Adm no: 2A-15(PhD)
Submitted to:
Dr Bireswar Sinha
Asst. Professor
DEPARTMENT OF PLANT PATHOLOGY, COLLEGE OF AGRICULTURE,
CENTRAL AGRICULTURAL UNIVERSITY, IMPHAL
PLPATH-604

2. INTRODUCTION
o Plant diseases are of paramount importance to humans and so is their
management evident from Important historical evidences of plant disease
epidemics such as Irish Famine due to late blight of potato (Ireland, 1845),
Bengal famine due to brown spot of rice (India, 1942) , Coffee rust (Sri Lanka,
1967) etc., which had left their effect on the economy of the affected
countries.
o Plant Diseases destructs crop production with annual contribution of
14.1%.
o Chemical control for plant disease has its concern on environment at large,
thus as alternative concept of molecular plant pathology & biotechnology sets
diagnostic tools , techniques for disease management.

3. Def: Plant biotechnology can be defined
as the use of tissue culture and genetic
engineering techniques to produce
genetically modified plants that exhibit
new or improved desirable characteristics.

4.  PRO’S
1) Desirable characters :
better yields & quality
greater resistance to adverse
factors, including diseases,
pests, and environmental
conditions such as freezes,
drought, and salinity.
2) Production of GM crop
plants that avoid or resist
certain plant pathogens.
 CON’S
1) Replaces numerous
sustainable
local varieties with few
genetically
engineered ones.
2) Development of pests and
pathogens that can resist OR
overcome the transformed
resistant crops.
3) Unknown numbers of
non target organisms affected
adversely .

5. RECOMBINANT DNA TECHNOLOGY
TISSUE CULTURE TECHNIQUE
RNA-INTERFERENCE TECHNIQUE
MECHANISMS
APPLICATION OF MOLECULAR
MARKERS

6. Plants have been
rendered resistant to
specific pathogens by
genetically
engineering
(transforming) them
with isolated specific
genes that provide
resistance against
these pathogens
known as transgene.
Transformed plants
become resistant
by coding for enzymes
that mobilize other
enzymes that carry
out numerous
defensive functions,
such as breaking
down the structural
compounds of the
pathogen.
MECHANISM
RECOMBINANT DNA TECHNOLOGY

7. Resistance against bacterial and fungal
diseases are sought to be generated by
expression of the following transgenes:
1) Genes encoding insensitive target enzymes.
2) Genes specifying toxin inactivation & expression of
antibacterial peptides, bacterial lysozymes.
3) Genes specifying heterologous phytoalexins &
thionins.
4) Ectopic expression of PRP’s, chitinases.
5) Genes specifying artificially PCD.

8. PROTOPLAST
FUSION:
Introgression of
genes for
resistance
CHEMICALLY
INDUCED FUSION:
Chemicals tends to
increase fusion.
Polyethyleneglycol
(PEG) is commonly
used as fusogen.
 Agrobacterium
tumefaciens or its
modified T-plasmid are
used to introduced
foreign DNA/RNA into
plant cell.
TISSUE CULTURE TECHNIQUES

9. RNA- interference technique
RNA Silencing, phenomena taking place.
Custom knock down of the gene activity.
Gene targeting in fungi, bacteria and virus.
DUE TO POST TRANSCRIPTIONAL
GENE SILENCING

10. MOLECULAR MARKERS IN DISEASE
MANAGEMENT
Molecular markers linked to various resistance
genes are used for marker assisted selection for
resistance breeding, gene pyramiding, map
based cloning of resistance genes.

11. Potato plants engineered with a chimeric gene encoding
two insect proteins exhibiting antimicrobial activities
showed significant resistance to the late blight oomycete
and their tubers were protected in storage from infection
by the soft rot-causing bacteria.
Raspberry plants engineered with the gene coding for the
common plant polygalacturonase-inhibiting protein (PGIP)
became resistant to the gray mold fungus Botrytis cinerea,
although the transgene in raspberry, but not in other
plants, is expressed only in immature green fruit.
APPLICATIONS
(A) TRANSGENIC PLANT DISEASE MANAGEMENT:

12. Indica rice varieties IR64, IR72, were co-transformed by
microbombardment of embryogenic suspensions with
plasmids that contain the Xa21 gene which confers
resistance to Xanthomonas oryzae pv. Oryzae.

13. Candidate Genes against Bacterial Pathogen: A Toxin
inactivating gene, “ttr” isolated from Pseudomonas
tabaci cloned into Tobacco cultivars showed wildfire
disease resistance.
Candidate Genes against Fungal Pathogen: PR- protein
like genes encoding chitinases and B-1,3 Glucanases
increases expression of individual and multiple PR –
proteins in various crops demonstrating enhanced
disease resistance against particular pathogens like e.g.,
in rice Rhizoctonia solani, the sheath blight pathogen.

14. ARTIFICIAL PCD(SINGLE COMPONENT SYSTEM)
:
In transgenic potato with barnase gene
under the control of infection specific
Promoter prp 1 – 1, ensures the control of
Phytophthora infestans by the action of
barnase protein, an RNAse leading to host cell
death along with the pathogen.

15. Nontoxic chemical substances
when applied to plants
externally, stimulate the
plants and elicit the activation
of their natural defense
mechanisms, i.e., activation of
the localized defense
mechanism (hypersensitive
response) and systemic-
acquired resistance (SAR). Two
such chemical substances used
commercially are Actigard &
Messenger
Actigard in one application
increases the plants’ resistance
against some bacterial and some
fungal diseases for several weeks,
and
Messenger, derived from the fire
blight bacterium gene coding for the
protein harpin, which elicits a
hypersensitive response and SAR in
plants
(B) DEVELOPMENT & USE OF NON TOXIC CHEMICAL SUBSTANCES

16. C) TISSUE CULTURE IN DISEASE MANAGEMENT
Disease Resistant Plants Produced from PROTOPLAST FUSION
SPECIES used for disease resistance
1. Latuca sativa against Downy mildew(Bremia lactucae)
2. Brassica oleracea and Raphanus sativus against club
root(Plasmodiophora brassicae)
3. Brassica napus & Brassica nigra against Black leg(Phoma
lingum) & club root
4. Solanum brevidens and Solanum tuberosum against Bacterial
soft rot(Erwinia spp)

17. RNAi IN DISEASE MANAGEMENT
RNAi Technology
has emerged as one of the most
potential and promising strategies
to combat diseases against fungi,
bacteria, virus & nematode.
 Amongst fungi, disease
resistance can be created against
includes Cladosporium fulvum,
Magnaporthae grisea, Venturia
inaequalis & Neurospora crassa.

18. CONCLUSION
PLANT BIOTECHNOLOGY HELPS PLANT PATHOLOGY IN MANY
WAYS SUCH AS
1) TO OBTAIN PATHOGEN FREE MOTHER PLANTS THROUGH
CLONAL PROPAGATION.
2) NEW PLANTS TO WHICH GENES OF DESIRE HAS BEEN
INCORPORATED THROUGH GENETIC ENGENEERING.
3) STUDY OF PLANT AND PATHOGEN GENES FOR
RESISTANCE AND VIRULENCE RESPECTIVELY HAS
CONSIDERABLY BEEN ADDED BY GENETIC ENGENEERING.
4) ALTHOUGH HAVING MANY BENEFICIAL SIDES TO PLANT
BIOTECHNOLOGY AND ITS APPLICATION, THEIR STILL
SEEMS TO OCCUR A LARGE LOOPHOLE TO BE MENDED.

19. REFERENCES:
1) Neelam Geat & Devendra Singh, IARI New Delhi, Role of
Biotechnology in plant disease management ,Biotech Articles ,
2015-10-31
2) Agrios G.N. (1969) Plant Pathology, Academic Press, 5th
edition, pg.56-58