India suffers post-harvest losses of over $2 billion annually due to spoilage of 30% of fruits and vegetables after harvesting. Elicitors are compounds that can activate natural host defense responses in plants. Some examples of elicitors that have been shown to reduce post-harvest diseases include salicylic acid, methyl jasmonate, harpin, and oligandrin. Elicitors work by priming the plant's defenses through mechanisms like reactive oxygen species production, phytoalexin production, and hypersensitive response. The effectiveness of elicitors can depend on factors like cultivar genotype, environmental conditions, and whether they are combined with other treatments like fungicides or biocontrol agents.

1. ACTIVATION OF NATURAL HOST DEFENCE BY
ELICITORS FOR MANAGEMENT OF POST
HARVEST DISEASES
Doctoral Seminar I
VINOD UPADHYAY
ID.NO- 44056
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2. India's post-harvest losses over Rs 2 L cr annually:
Assocham
30% of Fruits and vegetables - unfit for consumption due to
spoilage after harvesting
West Bengal(Rs 13,600 crore anually) >Gujarat (Rs 11,400 crore)>
Rs (10,700 crore) >Uttar Pradesh(Rs 10,300 crore)>Maharashtra (Rs
10,100 crore)
Additional requirement of cold storage - 370 lakh tons for fruits and
vegetables. Presently- total storage capacity for 300 lakh tons.
Total postharvest food loss -10-40% (FAO, 2010)
Highlights !!
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3. Losses would be enough to feed around 70–100 million people, i.e.
approximately a third of India’s poor (ICAR, 2010)
Loss of overall Resources….seed, labor, water..etc.
Food Security and Postharvest Loss
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4. INTRODUCTION
Compounds stimulating any type of plant defense
 Biotic or abiotic origin
 Production of ROS (reactive oxygen species)
 Hypersensitive response
 Production of phytoalexins, i.e. antimicrobial secondary
compounds
ELICITOR
Induction of plant defense
Elicitors may induce local acquired resistance (LAR), systemic acquired
resistance (SAR) or induced systemic resistance (ISR)
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5. CLASSIFICATION OF ELICITORS
PHYSICAL
• Radiation
• Heat
treatment
CHEMICAL
• Acibenzolar
• Chitosan
• Salicylic acid
• Jasmonic acid
• Methyl jasmonate
• Harpin
• Oligandrin
• Benzothiadiazole
BIOLOGICAL
• Penicillium funiculosum
• Glomerella cingulata
• Candida oleophila
• Aureobasidium
pullulans
• Phyllosticta musarum
• Colletotrichum magna
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6. EXAMPLES OF CHEMICAL ELICITORS TO
NATURAL DISEASE RESISTANCE TO POST HARVEST DISEASES
Terry et al.,2003 6

7. Effect of application of different elicitors on polyphenol content
and activity of polyphenol related enzymes
Garsia et al.,2013 7

8. Effect of application of different elicitors on polyphenol content
and activity of polyphenol related enzymes
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9. MECHANISM OF ELICITATION
Bubulya, 20129

10. NDR declines: Results in activation of quiescent infections
Factors affecting decline of NDR in produce after harvest :
(1) Nutritional requirements for the pathogen
(2) Preformed antifungal compounds (phytoanticipins)
(3) Potential for inducible antifungal compounds (phytoalexins)
(4) Activation of fungal pathogenicity factors
Prusky, 1996
NATURAL DISEASE RESISTANCE (NDR) AFTER
HARVEST
After harvest
1
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11.  Modify the plant-pathogen interaction by resembling an
incompatible interaction with defense-related mechanisms
 Mimic the action of the signaling molecules SA and JA and their
derivates
 Luckey (1980) - concept of inducing NDR ‘plant hormesis’
 Stimulation of a beneficial plant response by low or sub-lethal
doses of an elicitor/agent
PLANT HORMESIS
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12.  No risk of creating resistant pathogen strains
 Increase the phenolic content of fruit
 Protecting plants and fruits from biotic and abiotic stresses
 No impact on environment
 Pre harvest spray can also control postharvest losses
WHY TO FOCUS ON ELICITORS ?????
1
2

13. SIGNAL TRANSDUCTION PATHWAY FOR
CHEMICAL ELICITORS
Chan, 2013
1
3

14. APPROACHES TO CONTROL POST HARVEST DECAY
AND MECHANISM INVOLVED BASED ON PROTEOMIC STUDY
Chan, 2013
1
4

15. ELICITORS OF BIOLOGICAL ORIGIN
1
5

16. 1
6

17. HARPIN INDUCED RESISTANCE TO BLUE MOLD OF
APPLES
Control
Treated Capdeville et al.,Flocculent material
1
7

18. Control
Treated
WALL APPOSITION AND CONDENSED TANNIN
VACUOLES IN HARPIN TREATED APPLES
Capdeville et al., 18

19. HARPIN TREATED BEFORE HARVEST HARPIN TREATED AFTER HARVEST
120 days at 0.5°C plus 7 days at
20°C
120 days at 0.5°C
Diseasefruit
%
104spores/ml
103spores/ml
Capdeville et al.,
Diseasefruit
%
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20. 2
0

21. EFFECTS OF OLIGANDRIN ON DISEASE CAUSED BY
B. cinerea IN TOMATO FRUIT
Wang et al.,2011
At 25ºC
2
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22. CHANGES IN DEFENCE RELATED ENZYMATIC
ACTIVITIES IN TOMATO FRUIT
Incubated at 25°C
85 to 95% RH
Wang et al.,20112
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23. DEFENSE GENE EXPRESSION IN TOMATO FRUITS
INDUCED BY OLIGANDRIN
Wang et al.,2011
2
3

24. SYNTHETIC CHEMICAL ELICITORS
ASM
2
4

25. 2
5

26. EFFECTS OF BENZOTHIADIAZOLE AND METHYL JASMONATE ON
BANANAS INOCULATED WITH Colletotrichum musae
Cheng Ma et
BTH- 5 mmol/L
MeJA - 0.1 mmol /L
At 22ºC 2
6

27. EFFECTS OF BENZOTHIADIAZOLE AND
METHYL JASMONATE ON CHITINASE (MaChit) GENE
EXPRESSION
Cheng Ma et
al.,2009
2
7

28. 2
8

29. Effect of BTH on lesion area and disease incidence
in peach fruit inoculated with P. expansum
Liu et al.,2004
2
9

30. Effect of the BTH on activities of different
enzymes in peach fruit
Liu et al.,2004
3
0

31. PREHARVEST SPRAY AND POSTHARVEST
MANAGEMENT
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32. 3
2

33. Effects of pre-harvest ASM spray in Yali pear fruit
inoculated with P. expansum or A. alternata after harvest
P. expansum
A.
alternata
Cao et al.,2006
3
3

34. Effects of pre-harvest ASM spray on the activities of
defence related enzymes in Yali pear fruit after harvest
Cao et al.,2006
3
4

35. Cao et al.,2006
Effect of pre-harvest spray of ASM on activities of
different enzymes in young harvested pear fruit
3
5

36. 3
6

37. Effects of the Salicylic acid sprays in pear fruit
inoculated with P. expansum after harvest
Cao et al.,2006
3
7

38. EFFECTS OF THE SALICYLIC ACID SPRAY ON ACTIVITIES OF
DEFENSE RELATED ENZYMES IN THE YOUNG PEAR FRUIT.
Cao et al.,2006
3
8

39. Effect of the SA spray on activities of different
enzymes in the young pear fruit
Cao et al.,2006
3
9

40. COMPATIBILITY WITH BIOCONTROL AGENTS
4
0

41. 4
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42. Compatibility of methyl jasmonates with antagonistic
yeast Cryptococcus laurentii
Yao et25ºC 0ºC
Me Ja conc.
0µmol/l
50µmol/l
100µmol/l
200µmol/l
400µmol/l
4
2

43. Effect of Monilinia fructicola and Penicillium expansum
in peach fruit treated with MeJA and Cryptococcus
laurentii
Yao et
al.,2004
CK-Wounding +
pathogen
A- MeJA + pathogen
B- C. laurentii +
pathogen(less cfu)
C- MeJA
+C.laurentii
+ pathogen
D- C. laurentii +
pathogen(high cfu)
M. fructicola P. expansum
4
3

44. Effect of MeJA and Cryptococcus laurentii on
defense related enzymes in peach fruit
Yao et
25ºC 0ºC
4
4

45. Effect of MeJA and Cryptococcus laurentii on PAL
AND POD activity in peach fruit
Yao et
25ºC 0ºC
4
5

46. COMPARATIVE EFFECTIVENESS OF DIFFERENT
ELICITORS
46

47. 4
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48. Comparative effects of different elicitors on
management of Alternaria rot in pear
Tian et al., 2006
A - Salicylic acid
B - oxalic acid
C- calcium chloride
D - antagonistic yeast
E- untreated control
4
8

49. Comparative effects of different elicitors on
defense related enzymes in pear
Tian et al., 2006
4
9

50. FACTORS INFLUENCING THE EXPRESSION
OF INDUCED RESISTANCE
GENOTYPE
ENVIRONMENT
OTHER FACTORS
5
0
Walters et al.,2005

51. GENOTYPE:
Hijwegen and Verhaar (1994) - Resistance in cucumber to the powdery
mildew fungus induced by treatment with INA was cultivar dependent
Highest levels of induced resistance expressed in a partially resistant
cultivar
much lower levels of resistance in susceptible cultivars
Dann et al.(1998) - Resistance to Sclerotinia sclerotiorum induced by
treatment with INA or ASM in soybean was greatest in susceptible
cultivars
Oostendorp et al. (2001)- Resistance activated by ASM in monocots
are very long lasting compare to dicots
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52. Heil et al.(2000) - ASM applied to wheat in the absence of pathogen
 Reduced biomass
 Reduced numbers of ears and grains
 When nitrogen supply was limited effects was pronounced
Reductions in the expression of genes related to primary metabolism
following elicitation of resistance.
Dietrich et al. (2005)- Treated Arabidopsis plants with ASM -initial growth
reductions was compensated subsequently by increasing growth rates
ENVIRONMENT
COST OF INDUCED RESISTANCE
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53.  Effect of resistance induction on seed production was determined by
environmental conditions such as nitrogen supply, water stress, and
competition with other plants.
 Result - costs, no costs, or even higher seed production by ASM-induced
compared with uninduced controls under different combinations of
environmental factors.
Induced plants were most likely to incur fitness costs if grown in a
competitive environment.
Dietrich et al.(2005)
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54. Should a resistance elicitor be applied before or after a fungicide
application????
Depend upon the particular pathogen or pathogens being targeted and the stage
of crop growth
OTHER FACTORS
 Eg. Strobilurin fungicide + ASM - effective in controlling Albugo occidentalis
and increasing leaf quality in spinach
ASM + mancozeb- provide protection against Claviceps africana on
sorghum in case where fungal isolates resistant to the usual fungicide treatment
-triadimenol
 Timing of application and frequency of application
 Conjunction with appropriate-dose fungicides
COMBINATIONS
54

55. QUESTION NEED TO BE ANSWERED
Will incorporation of induced resistance into disease control programs
be more expensive than current approaches?
Will induced resistance represent a sustainable approach to disease
control???
Farmers and growers need to be convinced….
Whether it can replace the existing management practices????
Will it be feasible with other practice in integrated disease
management?????
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57. 5
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