2. Role of enzymes in plant disease development
Enzyme:
• Enzymes are large protein molecules (2-100
micrometer in diameter) which act as a
catalyst to bring a specific set of reactants to
specific product)
• A cell contains several million enzymes,
which belongs to different kinds of enzymes.
3. • Enzymes secreted by microorganisms play a major
role in disease development.These break down plant
substances into smaller molecules which pathogen
easily absorb and utilize for its growth and
Development.
• Different kinds of enzymes are reproduced by plant
Pathogen are
4.
5. CUTINASE:
Cutinase which degrade Cutin Is the main components of
cuticle is Known to produce by many fungi and
bacteria.
Eg Puccinia hordei.
6. Degrade pectic substances which is chief component
of middle lamella of plant cells.
Pectic enzymes classified under 2 major groups
Pectic esterases:
Catalyses the hydrolysis of methyl ester group of
Pectinic acid to methyl alcohol and pectinic acids of
Reduced methoxy content eventually to pectic acids.
Polygalacturonose (PG) :
Chain splitting enzymes which break the links
Between adjacent galacturanic acid.
PECTINASES:
7.
8. CELLULASE:
Produced by several plant pathogenic Fungi,bacteria
and Nematodes,which plays a major role in
Softening
Eg- Fusarium.
10. • Breakdown fungi resistant components
enzymaticdegradation, Lignin.
Lignin-It has high molecular weight.
It has basic unit is a phenylpropaniod
which forces a golymer.
Lignin is formed in the middle lamella, the
Cell walls of xylenin vessels and the eclursenchyma
Fibres as a secondary thickening that strengthen
Plants.
LIGNINASE:
11. PROTEASES
Which degrade proteins.
The degradation of host proteins by proteolytic
enzymes secreted by pathogen affects the
organization and function of the host cell.
Eg – Helminthosporium oryzae.
12. AMYLASES
Which breakdown starch into glucose and utilised by
the pathogen.
Fatty acid is directly utilized by the pathogen .
Eg-Many fungi, bacteria,and nematodes.-
