ROLE OF SECONDARY METABOLITES IN PLANT DEFENSE MECHANISM

Submitted ToThe Principal

Mahatma Gandhi missionCollege of Agricultural Biotechnology,

AurangabadAffiliated to Vasantrao Naik Marathwada

Krishi Vidyapeeth, Parbhani( ISO 9001:2008 Certified)

Submitted byShinde Devidas Raghu

Registration no-MGM/CABT/2011/65

Semester-VII (new) CS-4713Seminar guideAsst. professor -

V.D.DESHMUKHDepartment of Plant

Biotechnology

Sr.No Content Slide No.

1 Introducttion 32 Types of metabolites 33 Classification of

sec.metaboolites5

4 Resistance 65 Types of Resistance 66 Defense mechanism 97 Role of Sec.Metabolism 168 Applications 17

Index

ROLE OF SECONDARY METABOLITES IN PLANT DEFENSE MECHANISM

INTRODUCTIONPlants synthesize a vast range of organic compounds that are traditionally classified as primary and secondary metabolites.Primary metabolites compounds that have essential roles associated with photosynthesis, respiration, and growth and developmentExamples :- Phytosterols, acyl lipids, nucleotides, amino acids

Secondary metabolites organic molecules that are not involved in

the normal growth and development of an plant.

Absence of it does not result in immediate death, but in long-term impairment of the organism’s survivability, often playing an important role in plant defense.

Most of secondary metabolites, such as terpenes, phenolic compounds and alkaloids are classified based on their biosynthetic origin.

Do not have generally recognised roles in the photosynthesis, respiration, solute transport, translocation, nutrient assimilation and differentiation.

major role in the adaptation of plants to the changing environment and in overcoming stress constraints.

Examples;-solasodine,alkaloid,glycoalkoloide, Anthocynin, Flavonoids, Solanin, Alanine,Tomatidine,etc

Classification of secondary metabolites

1. Terpens

2. Phenollic compound

3. Nitrogen containing compound

Resistance

Ability or capability of plant to prevent itself from foreign invading pathogen .

Types of ResistanceTwo types of resistance.1. Horizontal resistance2. Vertical resistance

Horizontal resistanceAll plants have certain but not always the

same level of possibly unspecific resistance that is effective each of their pathogen such resistance is called as Horizontal resistance or it also called partial/polygenic/Quntitative

Probably controlled by several genes therefore the name

limited number of genes, usually less than 4 to 5 are most effective to resistance.

Several genes involved in partial resistance seems to exit their influence by controlling the numerous steps of physiological process in the plant that provide material and structure that makes up the defense mechanism.

Many cases one of these genes alone may be ineffective against the pathogen and play minor role in total horizontal resistance(minor gene resistance)

Vertical resistance

Race specific resistance is always controlled by one or few genes.so called as Monogenic. Oligogenic resistance

Race specific resistance inhibits the initial establishment of pathogen.

Complete resistance may be provided by single gene and it provide a resistance.

Ex- Wheat has 20 to 40 genes for resistance against leaf rust fungus puccnia recondite.

Also referred as Monogenic/R-gene resistance/race specific resistance.

Host and pathogen appears incompatible.Host responds with hypersensitive

reaction may appear immune or inhibit pathogen reproduction.

DefenseThe ability or capability to fight against the invading pathogens

Mechanism of Defense two kinds of defense mechanism viz.1. Active mechanism of defense.2. Passive mechanism of defense .

1.Chemical defenseDefense response in plants can be induced

by physical presence of fungal spore, pathogen, penetration, nonspecific elicitors.

Qualitative metabolites are a toxins that interfere the Geranium produces chemical compound in its petals to defend itself from Japanese beetles.

It produces the chemicals within 30 minutes of ingestion the paralyzes the herbivore plants have evolved many secondary metabolites involved in plant.

1.Local signalIt is first response activated before induction of expression and protein synthesis.Example:-Ion fluxes, reactive oxygen species(ROS) production photophosphorylation on cascade.

2. CytoskeletonDefense the attack of potential pathogen prior to penetration.plant defense protein as osmotin and chitinase are associated with cytoskeleton.

2.Mechanical defenses

The Thorns on the stem of raspberry plant, serves as a mechanical defense against the herbivory.

plant structural defenses on stems and leaves can deter, injure, or kill the grazer.

Some defensive compounds are produced internally but are released onto the plants surface.

Ex- resins, lignins, silica, and wax cover the epidermis of terrestrial plants

Very smooth and slippery structure making feeding difficult.

Some plants produces gummosis or sap that traps insects.

1.Thigmonastymovement of plant that occur in response

to touch, are used as a defense in some plant.The leaves of sensitive plant close up

rapidly in response to direct touch, vibration, or even electrical and thermal stimuli.

Ex-Mimosa pudica2. Leaf shedding and colour

Leaf shedding may be a response that provides protection against disease and pest such as leaf miners and gall forming insects.

change of leaf color prior to fall of pathogen.

plants leaves stem may be covered with sharp prickles, spines, thorns, or trichomes hairs on the leaf often with barbs, sometimes containing irritants or poisons.

. plant structural features like spines and

thorns reduce feeding Branching and leaf arrangement may also

to reduce herbivore impact. In coconut and other palms, may protect

their fruit by layers of amours special skills to climb the tall and relatively smooth trunk.

Plant disease resistancePlant protects by two ways viz. by

preformed mechanisms and by infection-induced responses of the immune system

Disease resistance is the reduction of pathogen growth on or in the plant

disease resistance describes plants that exhibit little disease damage despite substantial pathogen levels.

Plant disease resistance is crucial to the reliable production of food,

provides significant reductions in agricultural use of land, water, fuel and other inputs.

Plants in both natural and cultivated populations carry inherent disease resistance, but this has not always protected them.

Non-protein amino acids Many plants also contain unusual

amino acid called non-protein amino. They exert their toxicity. block the synthesis of or uptake of

protein amino acid while other can be mistakenly incorporated into protein.

After ingestion, canavanine is recognized by herbivore enzyme plants that synthesize non-protein amino acids are not susceptible to the toxicity of these compounds but gains defense to herbivorous animals, insects and pathogenic microbes.

Role of Secondary Metabolites in Defense

For protect the plant from invading pathogens

Helps to improve the shelf life of plant. Helps to keep the the plant healthy. Decreases the infection by some diseases

and pests also. Useful in preparation of perfumes, or

aromatic substances. It has virtually imp in attracting the

animals for pollination. Sometimes for else were for seed

dispersal. Decreases the use of

insecticides,pesticides,and fungicides also.

It improves the immunity of plant. Such chemical compounds useful in

preparation in coloring substances.

.

Applications

It has wide application in pharmaceutical.

In production of insecticides. In preparation of pesticides. In drug development. In preparation of antibiotics. Useful for the defense purpose. In plant it regulate the metabolism

process. It acts as coloring agents itself

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