Plant pathogenic bacteria are economically important as both harmful and beneficial agents. While some bacteria cause plant diseases, others are exploited for uses like fermentation, chemical manufacturing, bioremediation, and pest control. Bacterial plant pathogens can be difficult to control without chemicals due to lack of effective alternatives and risk of antibiotic resistance.

2. TOPIC:TOPIC:IMPORTENCE OFIMPORTENCE OF
PLANTPATHOGENICPLANTPATHOGENIC
BACTERIABACTERIA

4. The BacteriaThe Bacteria
Cells are prokaryotic and amongst the
smallest known cells ( length 0.5-20 µm ).
No membrane bound nucleus.
Have ribosomes,but no other organelles.
DNA present as a long circular molecule.
( see handout for bacterial structure)

5. HabitatHabitat
Bacteria are found everywhere.
Air
Water
Soil
On plants and animals.
In plants and animals.

6. Types of BacteriaTypes of Bacteria
There are three major
groups of bacteria based
on their shapes; coccus,
bacillus, and spirillum.

7. 1. Coccus1. Coccus
Plural is cocci.
Spherical bacterium
Single cells -
monococci
Pairs - diplococci
Chains -
streptococci

8. 2.Bacillus2.Bacillus
Plural is bacilli.
A rod - shaped
bacterium.
Exists as single cells,
in pairs (diplobacilli),
and in chains
(streptobacilli).

9. 3. Spirillum3. Spirillum
Plural is spirilli.
A spiral - shaped
bacterium.
Exist only as
single cells.

10. Bacterial StructureBacterial Structure
Cell Wall - outermost
structure of the cell.
Made up of a substance
called peptidoglycan
( a long chain of sugars
linked to amino acids ).
Penicillin destroys
bacteria by interfering
with the peptidoglycan
molecules.

11. Bacterial Structure ContinuedBacterial Structure Continued
Cell Membrane -
Found beneath the cell
wall.
May be folded inward.
ATP production
(energy), takes place
on the folds of the
membrane.

12. Bacterial Structure ContinuedBacterial Structure Continued
Capsule: This is a layer
of slime secreted over
the cell wall of the
bacterium.
The capsule provides
protection for the
bacterium.
Bacteria that have
capsules are said to be
encapsulated.
Most pathogenic bacteria
are encapsulated.

13. Bacterial Structure ContinuedBacterial Structure Continued
Flagella - Some
bacteria in the bacilli
and spirilli categories
can move by way of
flagella ( whip - like
structures that propel
the bacteria).
Note: Cocci do not
have flagella.

14. Bacterial Physiology-Bacterial Physiology-
Nutritional NeedsNutritional Needs
Like all living things bacteria need food.
Bacteria are placed in one of two
categories, depending on how they get
their food.
The two categories are: Heterotrophic
bacteria and Autotrophic bacteria.

15. Heterotrophic BacteriaHeterotrophic Bacteria
Heterotrophs must get
their food from a source
of pre-formed organic
matter:
(A) Saprobes- feed on
the remains of dead
plants and animals.
(B) Parasites - live on
or in the organism and
cause disease. For
example, Mycobacterium
tuberculosis.

16. Autotrophic BacteriaAutotrophic Bacteria
Autotrophs can make
their own food:
Photosynthetic-use a
special type of chlorophyll
called
bacteriochlorophyll.
O2 is not released in
bacterial photosynthesis
Chemosynthetic -obtain
energy by breaking down
inorganic material such
as iron or sulfur.

17. Bacterial Physiology-ReproductionBacterial Physiology-Reproduction
The growth of bacteria is limited by the
following factors:
temperature
pH
moisture content
nutrient availability
competition from other organisms

18. Bacterial Physiology-ReproductionBacterial Physiology-Reproduction
continuedcontinued
Bacteria reproduce
asexually by
binary fission.
Using this process
bacteria reproduce
about every 20
minutes.

19. Bacterial Physiology-Bacterial Physiology-
Reproduction continuedReproduction continued
The rate of
reproduction can be
plotted in a graph
called a Growth
Curve.
Under ideal conditions
one bacterial cell can
produce a mass of 2
million Kg in 24 hours.
In reality this never
happens. Why?

20. IMPORTENCE OFIMPORTENCE OF
PLANTPATHOGENIC BACTERIAPLANTPATHOGENIC BACTERIA
The economic importance of
bacteria derives from the fact that bacteria
are exploited by humans in a number of
beneficial ways.
Despite the fact that some bacteria play
harmful roles, such as causing disease and
spoiling food, the economic importance of
bacteria includes both their useful and
harmful aspects.

21. Pathogenic bacteria:
Known as germs or pathogens
Cause disease
Can produce poisonous toxins
E. coli produce endotoxins
Exotoxins are made
of protein by Gram + bacteria
Clostridium
tetani produce exotoxins

22. BACTERIA

23. Antibiotics interfere with cellular
functions (Penicillin interferes with
synthesis of the cell wall; tetracycline
interferes with protein synthesis)
Some antibiotics are made by
bacteria or fungi
Broad-spectrum antibiotics affect
a wide variety of organisms
Bacteria can mutate and become
antibiotic resistant (often results
from overuse of antibiotics)

24. Biotechnology and bacteria
BIOTECHNOLOGY (or) INDUSTRIAL
MICROBIOLOGY is defined as the use of
micro organism such as bacteria, fungi and
algae for the manufacturing and services
industries.
Useful Bacteria

25. Fermentation processes, such as
brewing, baking, cheese and butter manufacturing,
Bacteria, often Lactobacillus in combination
with yeasts and fungi, have been used for
thousands of years in the preparation
of fermented foods such as cheese, pickles, soy,
sauce, sauerkraut, vinegar, wine, and yogurt.

26. •Chemical manufacturing such as
ethanol, acetone, organic acid,
enzymes, perfumes etc. In the
chemical industry, bacteria are most
important in the production of
enantiomerically pure chemicals for
use as pharmaceuticals or
agrochemicals.[1]

27. Genetic engineering and bacteriaGenetic engineering and bacteria
Using biotechnology techniques, or bio
medical technology bacteria can also
be bioengineered for the production of
therapeutic proteins, such as insulin
growthfactors or antibodies.

28. Bacteria are used to separate fibres of
jute, hemp, flax, etc., the plants are
immersed in water and when they swell,
inoculated with bacteria which hydrolyze
pectic substance of the cell walls and
separate the fibres.
These separated fibres are used to make
ropes and sacks.
Fibre retting

29. Digestion The bacteria present in the
stomach of cattle will help in the digestion
of cellulose.
Vitamin synthesis
Escherichia coli that lives in the human
large intestine synthesize vitamin B and
releases it for human use. Similarly,
Clostridium butyclicum is used for
commercial preparation of riboflavin, and
vitamin B.

30. DIGETION OF
CELLULOSE
FIBER
RETTING

31. Pest control
Bacteria can also be used in the place
of pesticides in the biological pest control.
This commonly uses Bacillus thuringiensis (also
called BT), a Gram-positive, soil dwelling
bacterium.
 This bacteria is used as a Lepidopteran-
specific insecticide under trade names such as
Dipel and Thuricide.
Because of their specificity, these pesticides are
regarded as Environmentally friendly, with little
or no effect on humans, wildlife, pollinators, and
most other beneficial insects.

32. Bacillus thuringiensisBacillus thuringiensis

33. Harmful bacteria
Some bacteria are harmful and act
either as disease-causing agents (
pathogens) both in plants and
animals, or may play a role in food
spoilage.

34. In addition, bacterial plant pathogens are
particularly difficult to control because of the
shortage of chemical control agents for
bacteria, apart from antibiotics.
However, the use of antibiotics is restricted
in many countries due to the potential for
evolution of antibiotic resistance and the
transmission of antibiotic resistance to
bacteria that can cause human disease.

35. Plant pathogenic bacteria
Bacterial plant pathogens is a major
problem worldwide for agriculture.
Besides bacterial pathogens that are
already established in many areas, there
are many instances of pathogens moving to
new geographic areas or even the
emergence of new pathogen variants.

36. AGENTS OF DISEASEAGENTS OF DISEASE
Bacteria are pathogenic and cause
diseases both in animals and plants.
However, pathogenic bacteria more
commonly affect animals than plants.
Certain bacteria that exist in the normal
flora on skin and in the mouth and human
intestine are also known to cause disease

37. Saprotrophic bacteria attack and
decompose organic matter such as stored
grains, meat, fish, vegetable and fruits
are attacked by saprotrophic bacteria

38. Biodetergents:
Microbial products like glycolipids from
Pseudomonas aeruginosa, Rhodococcus
erythropolis and Bacillus subtilis have
been found to possess characteristics
similar to detergents and are, therefore,
used for preparation of environment-
friendly biodetergents and biosurfactants.
They are used for emulsification, wetting,
dispersion solubilization, etc.

39. Biofuel:
The depletion of fossil fuel supplies with in
the few years had led to the search for
alternative energy sources.
Apart from geothermal, nuclear, wind, water
and solar energy, butanol fermentation
involves species of Clostridium.
Although yeast is exclusively used for ethanol
production, commercial potential of bacteria
like Zymomonas mobilis, Clostridium
thermocellum, Thermoanaerobacter, etc.

40. Bioremediation:
Metal-resistant bacteria like
Pseudomonas, Bacillus, Alcaligenes,
etc. helps in cleaning up of soil and
water contaminated by heavy
metals.

41. Biomining:
The environment-friendly method of
extracting minerals utilizing bacteria that
leach or solubilize metals from its ore is
referred to as biomining. Acidophilic
sulphur oxidizing bacterium, Thiobacillus
ferroxidans plays a major role

42. Antibiotic Bacteria
Bacitracin Bacillus licheniformis
Polymyxin B Paenibacillus polymyxa
Streptomycin Streptomycin
Neomycin S. fradiae
Chloramphenicol S. venezuelae
Tetracyclin S. rimosus
Erythromycin S. erythreus
Nystatin S. noursei
Amphotericin B S. nodosus
Some common antibiotics and their producer organisms

43. Antifungal drugs:
Several antifungal antibiotics are currently
available for treating infectious disease. One
example is griseofulvin, which is used against
the fungi of ringworm and athlete's foot. Other
examples are nystatin, clotrimazole,
ketoconazole, and miconazole, all of which are
used against vaginal infections due toCandida
albicans. For systemic fungal infections, the
antibiotic amphotericin B is available, although
it has serious side effects.

44. Antiviral drugs. Antiviral drugs are not
widely available because viruses have few functions
or structures with which drugs can interfere.
Nevertheless, certain drugs are available to
interfere with viral replication.
One example is azidothymidine (AZT), which is
used to interrupt the replication of human
immunodeficiency virus. Other examples
are acyclovir, which is used against herpes viruses
and chickenpox viruses ; ganciclovir, which is
used against cytomega-lovirus ; amantadine,
which is prescribed against influenza viruses;
and interferon, which has been used against
rabies viruses and certain cancer viruses.

45. Antiprotozoal drugs: Many antibiotics
used against bacteria, for example,
tetracycline, are also useful against protozoa.
Among the drugs used widely as antiprotozoal
agents are metronidazole (Flagyl), which is
used against Trichomonas
vaginalis; quinine, which is used against
malaria; and pentamidine isethionate, which is
valuable against Pneumocystis carinii.

46. Drug resistance:
Over the past decades, drug-resistant strains
have developed in bacteria. These strains
probably existed in the microbial population, but
their resistance mechanisms were not needed
because the organisms were not confronted with
the antibiotic. With widespread antibiotic use, the
susceptible bacteria died off, and the resistant
bacteria emerged. They multiplied to form
populations of drug-resistant microorganisms.

47. Proteins: R DNA technology has allowed
production of many therapeutic protein
and peptide like insulin, human growth
hormone, etc. Therapeutic proteins have
also been developed for treatment of
cancer and viral diseases, cardiovascular
diseases, neurological disorders, etc.
Apart from escherichia coli, Bacillus
subtilis and Pseudomonas aeruginosa
have been used for preparation of these
coat effective recombinant drugs.

48. Amino acids: Microbial production of
important amino acids is preferred because
they are biologically active. They can be used
as a supplement for animal as well as
vegetable proteins as food additives for
improve taste and for pharmaceutical
preparations.
Several bacteria like Corynebacterium,
Arthrobacter, Brevibacterium, etc. produce
large amount of aminoacids in the cultural
medium from where it is isolated and later
purified. Commercially produced aminoacids
include lycine, glutamic acid and methionine
etc.

49.  Organic acids: Acetic acid, citric acid,
lactic acid, glucanoic acid etc are produced from
microbial fermentation and used in the food
industry as an acidulant and flavoring agent.
They are also used in electroplating detergen
,industry and pharmaceutical processes.
Vinegar is a condiment containing 4% acetic
acid. It is produces from maple syrup,
molasses, honey, cereals, root starch, etc. or
alcoholic beverages like wine, cider, spirit
alcohol, etc. Acetic acid fermentation occurs
under aerobic condition using strains of
Acetobacter and Gluconobacter

50. VACCINE DISEASE
Live attenuated vaccine
Bacillus anthracis Anthrax
Salmonella typhi Typhoid
Inactivated vaccine
Neisseria meningitides Meningites
Vibrio cholerae Cholera
Toxoids
Clostridium tetani Tetanus
Corynebacterium diphtheria Diphtheria
Examples of some bacterial vaccines applied for medical use:

51. Enzyme Source Source
Amylase B. subtilis
B. licheniformis
Starch proceesing
glucose isomerase
Pullulanase Klebsiella aerogenes Starch processing
Isomerase B. coagulan
Streptomyces galbus
Production of syrup
protease B. subtilis Biological
detergents , meat
tenderization and
cheese manufacture
Alkaline protease B. licheniformis Landuary
detergents
Examples of some bacterial enzymes and their industrial application

52. Products Raw ingredients Fermenting
microorganisms
Fermenting
microorganisms
Milk Lactobacillus
acidophilus
Soft Cheese (unripened)
Cottage Milk curd lactococcus lactis,
Leuconostoc citrovorum
Soft cheese ( Ripened, 1-
5 months0
Camembert Milk curd lactococcus lactis,
Lactococcus cremoris
Examples of fermented dairy products and microorganisms
involved in their production

53. Semi-soft Cheese
(Ripened, 1-12 months)
Roquefort Milkcurd Lactococcus lactis ,
Lactococcus cremoris,
Hard cheese (Ripened ,
3-12 months)
Cheddar Milk curd Lactococcus lactis, Lactobacillus casei,
Lactococcus cremoris, Strptococcus
durans
Yogurt Milk, Streptococcus thermophilus,
Lactobacillus
milk
solids
delbrueckii ssp. bulgaricus