mycorrhizae as biocontrol agent

1. Mycorrhizae as biocontrol
agent
GUIDED BY:-
(Prof. H K kehri)
MADE BY:-
Deepak Yadav
(M.sc. Iv –sem.)

2. What is Mycorrhizae?
2
ares

3. Evolution
• Life first emerged on land = pre-cambrian
period
• Zygomycete hyphae = Cambrian
• Endomycorrhizas = Devonian period,
discovered by Kidstone & Lang
• Fossil mycorrhizas were first discovered
by Weiss(1904) in lower carboniferous.
3

4. Discovery
• Symbiosis was studied by Franciszek
Kamieński in 1879–1882.
• Albert Bernhard Frank, who
introduced the term mycorrhiza in
1885.
4

5. 5

6. Kinds of Mycorrhizae
• Marks (1991) classified on the basis of types of
relationships with the hosts .
• Ectomycorrhiza =Harting nets……ascomycetes and
Basidiomycetes
• Endomycorrhizae =The fungus grows within the cortical
cells.
• Ectendomycorrhiza
• Vesicular Arbuscular Mycorrhiza
• Arbutoid Mycorrhiza
• Monotropoid Mycorrhiza
• Ericoid Mycorrhiza
• Orchid Mycorrhiza
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7. 7

8. Distribution of Mycorrhizal Fungi
HOST
• 83% Dicots
• 79% Monocots
• 100% Gymnosperms
• Cherry, Coconut , Hibiscus,
Banana ,Garlic = ENDO
• Eucalyptus , Pine, Cypress,
Poplar = ECTO
• Cedar ,willow=ENDO &
ECTO
NON HOST
• Amaranthaceae,
Brasicaceae,
Caryophyllaceae,
Chenopodiaceae,
Commelinaceae,
Lecythidaceae,
Portolaceae, Proteaceae,
Restionaceae,
Sapotaceae,
Zygophyllaceae
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9. VAM as biocontrol agent
The prodigious research made during last four decades
clearly established its widespread occurrence in
various plants species and under different agroclimatic
conditions covering broad ecological range including
deserts,forests and mangroves.
It established that this symbiotic association benefits
the plants through enhanced nutrient uptake,
biological control of root pathogen and synergistic
interaction with nitrogen fixing
microorganisms,hormones production and drought
resistance.
9

10. This biotool has now attracted the attention of
microbiologist, agronomists, horticulturists and
foresters at the global level.
Extensive studies have explored the possibility
of using mycorrhizal model system in inducing
suppressions of potential soil-borne pathogens.
Its relevence becomes all the more important
since most of the soil-borne diseases, by and
large, are not easily controlled by conventional
method.
10

11. Interaction of vam fungi and fungal pathogen
results in decrease in severity of disease,thus the
vam fungi determine the severity of the disease
they may be used as biocontrol agents.
Morphological, anatomical, biochemical or
physiological changes in the host due to
mycorrhization may suppress the pathogen and
its activity and imparts resistance against it.
It curtails the damage caused by the pathogen
resulting in a curtailment of disease expression.
11

12. Mycorrhizal roots are functionally longer than
non- Mycorrhizal ones,and are less susceptible
to certain types of pathogen attack.
The major relevance is in the control of soil
borne diseases,
12

13. Success of VAM fungi as biocontrol agent has
been established beyond doubt as they proved
their potential to check a number of soil-borne
diseases including root rot of tomato due to
Fusarium oxysporium f. sp. radices lucopersici
(Caron et al. 1986) and root rot of green gram,
black gram and chick pea due to
Macrophomina phaseolina, (Kehri and
Chandra,1990,Chandra et. al.,1995)
13

14. Physiological alterations
Qualitative and quantitave differences in chemical
constituents in roots of mycorrhizal and non
mycorrhizal plants,
Higer level of amino acids specially arginine have
been reported in the mycorrhizal plant species,
High level of chitinolytic activity has been reported
in mycorrhizal roots and it is suggested that the
chitinolytic enzymes are produced by the host for
the digestion of arbuscules
14

15. Mycorrhizal roots have been reported to exhibit a
low level of starch but higher level of soluble
carbohydrate and reducing sugar.
mycorrhizal roots have been shown to contain more
phenols than non mycorrhizal roots.
accumulation of phenols in root tissue of mycorrhizal
plants has been reported to be the cause of
inhibition of growth of pathogen like Sclerotium and
Fusarium in tomato.
15

16. COMPETITION FOR PHOTOSYNTHATE
In plants, a pathogen shares the photosynthate
produced by the host
In mycorrhizal plants loss in carbon is compensated by
increase in photosynthesis, which may inturn nullify
the growth depression
Carbon drain is eliminated due to additional
photosynthate produced by the host as a result of
mycorrhizal association.
16

17. 17
Competition for photosynthate

18. ROOT EXUDATES
The root exudates affect the pathogenesis of root pathogen.
Exert a favorable effect or unfavorable effect on germination or
penetration of pethogen
Exert the same effect on the pathogen directly through the non
pathogenic root microflora which have a important role in
pathogen activity
Alternation in pattern of root exudation due to VAMassociation
proposed to be causal of soil borne disease reduction
VAM symbiosis reported to be regulated by amount of nutrients
that is amino acids and reducing sugars. 18

19. 19
For collection of exudates

20. 20Root exudates

21. Higher root exudation in the zone root elongation, the zone
most susceptible to VAM colonization.
Mycorrhization induce qualitative and quantitative changes
in the root exudatin resulting in a modification of microbial
population in rhizosphere and rhizoplane modification
encourages or suppresses the activity of pathogen and
pathogenesis
Resistance against the pathogens due to additional
metabolities in root exudates change in quantity of a
specific metabolite related to the activity of pathogen.
21

22. COMPETITION FOR SPACE
VAM fungi and pathogen share the space in the
tissue of roots , competiton for space between the
two share holders
VAM symbiont provides additional root tissue
increasing growth of roots resultant of improved
nutrition, competition hypothesis for resistance
has been doubted.
Pathogen fungus reduce the apex diameter and
the number of mitoticaly active and viable apices
inducing plasmolysis,cell and nucleus degeneration
and necrosis. 22

23. 23
Competition for space

24. The AM fungus produced an increase in apex size and
reduced the percentage of necrosis both uninfected and
infected roots
AM fungus protected the apices from the pathogenic
infection,allowing normal root growth.
Thus produced thicker roots, might indirectly contribute to
plant protection.
Increased volumes of colonizable tissues favour the spreading
the symbionts.
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25. 25
Competition for space

26. Primary goal of mycorrhizal inoculation
• Improve the uniformity of tree growth
• It produce fruiting bodies
• Increase resistance
• Increase the diversity of soil fungi
• Inoculate any size of plant by spraying or
dusting the roots, drenching containerized
plants or incorporating the mycorrhizal spores
into growing media.
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27. 27
Mycorrhizal spores

28. How does the AM fungus benefit?
AM fungi are “obligate symbionts”
• They must live in symbiosis with plants to
complete their life cycles
• Why?
– Metabolic division of labor among the structures
of the fungus
– Only the fungus within the root can absorb sugars
for energy and make lipids necessary for storage
and growth
– Germinating spores can only grow as long as their
stored lipids hold out

29. Tips to Choose a Quality Mycorrhizal
Inoculant
Some researchers lucky enough to find an
excellent manufacturer.
• Spore count
• The quality of the manufacturing process
• The health of the spores
• Cost price
• Ectomycorrhizal inoculant are more plentiful.
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30. Collection of plant sample-
• The plant samples both healthy and diseased
(arhar plants) were collected from-
• phaphamau, Allahabad and;
• pratapgarh

31. MATERIAL AND METHODS
31
MYCORRHIZAE

32. Slide preparation of Mycorrhizal roots-
Root washing with water
Cut roots into small 1 cm pieces
Washed with 10% KOH for 24 hrs at room temp.
Washed with water
Kept solution in 3% Sodium hypochlorite
Washed with water

33. Kept in HCl for 3-4 mints.
Kept in tryphanblue for 24 hrs at room temp .
Kept in destain
Stained roots were kept on slide and were covered with cover slip
Observed under microscope

34. MYCORRHIZAL SPORE ISOLATION
34
Take rhizospheric soil with roots
↓↓
Take a beaker full of sterilized water(50ml)
↓↓
Dissolve the soil of rhizosphere with roots in beaker
↓↓
Dissolve the soil with magnetic stirrer or glass rod
↓↓
Sieve the water in beaker by placing whatman filter paper
↓↓
Wach the filter paper under microscope
↓↓
Pick the spores with needle
↓↓
Place it on slides,by putting glycerine and cover slip

35. 35Root-bits of mycorrhizal infection

36. Root–bits on slide
Root–bits on slide

37. % Root bits infected
Locality Healthy plant Diseased plant
pratapgarh
Field-1 70% 20%
Field-2 70% 10%
Field-3 80% 30%
phaphamau
Field-1 80% 40%
Field-2 80% 25%
Field-3 70% 20%
Table-1 Mycorrhizal intensity in the roots of healthy and wilted plants of arhar growing
in the fields of pratapgarh and phaphamau
RESULT

38. 0
10
20
30
40
50
60
70
80
90
Field 1 Field 2 Field 3
%Rootbitsinfectedinhealthyanddiseasedplantsofarhar
Healthy plants Diseased plants
Wilted plant at pratapgarh

39. 0
10
20
30
40
50
60
70
80
90
Field 1 Field 2 Field 3
%rootbitsinfectedinhealthyanddiseasedplantsof
arhar
Healthy plants Diseased plants
Wilted plant at phaphamau

40. % Root bits infected
Locality Healthy plant Diseased plant
pratapgarh
Field-1 80% 10%
Field-2 70% 20%
Field-3 70% 10%
phaphamau
Field-1 80% 40%
Field-2 80% 30%
Field-3 70% 20%
Table-2 Mycorrhizal intensity in the roots of healthy and fusarium infected plants of
arhar growing in the fields of pratapgarh and phaphamau

41. 0
10
20
30
40
50
60
70
80
90
Field 1 Field 2 Field 3
%rootbitsinfectedinhealthyanddiseasedplantsofarhar
Healthy plants Diseased plants
infected plant at pratapgarh

42. 0
10
20
30
40
50
60
70
80
90
Field 1 Field 2 Field 3
%rootbitsinfectedinhealthyanddiseasedplantsofarhar
Healthy plants Diseased plants
infected plant at phaphamau

43. % Root bits infected
Locality Healthy plant Diseased plant
pratapgarh
Field-1 80% 10%
Field-2 70% 20%
Field-3 70% 20%
phaphamau
Field-1 70% 20%
Field-2 70% 10%
Field-3 80% 10%
Table-3 Mycorrhizal intensity in the roots of healthy and Fusarium infected plants
of arhar growing in the fields of pratapgarh and phaphamau

44. 0
10
20
30
40
50
60
70
80
90
Field 1 Field 2 Field 3
%rootbitsinfectedhealthyanddiseasedplantsofarhar
Healthy plants Diseased plants
Fusarium infected plant at pratapgarh

45. 0
10
20
30
40
50
60
70
80
90
Field 1 Field 2 Field 3
%rootbitsinfectedinhealthyanddiseasedplantsofarhar
Healthy plants Diseased plants
Fusarium infected plant in phaphamau

46. Result
Healthy and wilted plant from pratapgarh and phaphamau-
the mycorrizal intensity is greater in phaphamau fields than
pratapgarh .
Healthy and infected plants-
The mycorrizal intensity is greater in phaphamau than
pratapgarh.
Healthy and Fusarium infected plant –
Mycorrizal intensity is same in pratapgarh and phaphamau
fields . Their same intensity in both places healthy plants
and Fusarium infected plants.

47. 64%
66%
68%
70%
72%
74%
76%
78%
80%
82%
Field 1 Field 2 Field 3
%rootbitsinfectedinhealthyplantofarhar
Healthy Plant
phaphamau
pratapgarh

48. 0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
Field 1 Field 2 Field 3
%rootbitsinfectedinwiltedplantofarhar
Wilted Plant
phaphamau
pratapgarh

49. 0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
Field 1 Field 2 Field 3
%rootbitsinfectedinplantofarhar
infected Plant
phaphamau
pratapgarh

50. 0%
5%
10%
15%
20%
25%
Field 1 Field 2 Field 3
%rootbitsinfusariuminfectedplantofarhar
Fusarium infected Plant
phaphamau
pratapgarh

51. References
• Bagyaraj, D.J. (1984). Biological interactions with VA mycorrhizal
fungi. In: VA mycorrhizae (eds.). C.L. Bailey and J.W. Mansfield.
CRC Press, Boca Raton, Florida,USA, pp.131-154.
• Brundrett, M., Bougher, N., Dell, B., Grove, T and Malajczuk, N.
(eds.) Working with mycorrhizas in forestry and agriculture,
02/01/1995, Publication Code: MN032
• Crush, J.R. (1974). Plant growth response to vesicular-arbuscular
mycorrhizal. VII. Growth and nodulation of some herbage
legumes. New Phytologists, 73: 743-749.
• http://www.sciencedirect.com/science/article/pii/S0166248108702
009
• HTTP://WWW.JSTOR.ORG/DISCOVER/10.2307/2442619?UID=2&UI
D=4&SID=21105407197063
• HTTP://WWW.DAVIDMOORE.ORG.UK/ASSETS/MOSTLY_MY
COLOGY/DIANE_HOWARTH/ERICOID.HTML
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