role of phenolic compounds in plant disease resistance prepared and presented by sachin verma

1. Course Instructor
Dr. S.R.MISHRA
Professer & HOD
Department of Agril.Meteorology
Submitted by-
Akhilesh Gupta
ID.NO. A-13174/22
Master’s Seminar
Department of Agricultural Meteorology
Topic –
ACHARYA NARENDRA DEVA UNIVERSITY OF
AGRICULTURE AND TECHNOLOGY AYODHYA

2. Phenolic compounds
Phenolic are aromatic benzene ring compounds
which is attached with one or more hydroxyl
groups.
 It is produced by plants mainly in stress conditions.
 Play important role in lignin and pigment biosynthesis.
 Phenolic compounds are toxic to pathogens .
 Usually they kill the microorganism or pathogen.
 They accumulate faster after infection.
 In resistant variety the phenolic compounds secreted are
accumulated fastly.
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White bars
•Represents
normal plants
Dark Bars
•Represents
transgenic plants
FIGURE
A,C,E
• IT REPRESENTS
NORMAL WOUNDED
PLANTS
FIGURE
B,D,F
• IT REPRESENTS
SPRAYED ELICITATION
COMPOUND ON
PLANTS

7. ROLE OF PHENOL OXIDIZING ENZYMES IN
DISEASE RESISTANCE
POLYPHENOL OXIDASES
Basically they oxidise phenolic compounds
to Quinone which is more toxic rather than
phenolic
PEROXIDASES-
Rate of Polymerization is increased
Deposited in cell wall and papillae and
interfere with growth of pathogen.
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8.  Resistant genotypes of castor and potato against fusarium
oxysporium and pactobacterium respectively showed
increased PAL activity in both pathogen inoculated and
non inoculated pathogens.
 Foliar application of salicylic acid reduces root knot
nematode population and no. of gall formation in tomato
plants.
Role in plant disease management
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9. IMPORTANCE OF PHENOLIC COMPOUNDS:
1. Phenolic compounds, such as strigol, which stimulate
activation and germination of propagules of some
pathogens; and isoflavones and other phenolic, amino
acids, and sugars released from plant wounds that
activate a series of genes in certain pathogens leading
to infection.
2. Phenolic play important roles in plant development, of
lignin and pigment biosynthesis.
3. They provide structural integrity and scaffolding support
to plants.
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10. ADVANTAGES
 They are stable to
heating and drying.
 They are unaffected by
organic compounds.
 Highly toxic to fungi
 Role in induce defense
against abiotic stress and
insect attack too
DISADVANTAGES
 When used in pure form
harmful for tissues.
 It has not a longer time
sustainability.
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11. CONCLUSION
Phenolic compounds play significant role in
plant disease resistance,
In stress condition plant induced phenolics
compounds by PR-proteins,
Preformed phenolics compound show
defense mechanism by inducing resistance
in plants before arrival of pathogen.
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