Horizontal And Vertical Resistance In Plants

Horizontal and Vertical resistance in plants are the opposing force or blocking force that protects the plants from the attack of different pathogens.



Different plants has thier own ability to fight against pathogenic attack. Some plants are highly resistant and some are easily attacked by pathogens.



The resistance in plants is done by some kind of genes say:- R-gene. These genes code for specific material in response to certain pathogenic attack.



Based on the presence of type of resistance gene-There are 2 types of resistance in plant pathology. They are discussed below.So- Read the Post till end.



Types Of Resistance In Plants


The two type of resistance in plant are:-

1.Horizontal Resistance
2.Vertical Resistance


Before we directly jump into detailed overview of these type of plant resistance.Lets have a look on the difference between these two types of resistance in plant:-

Features.          Horizontal resistance           vertical resistance            
1.Other Names
2.Nature Of Gene ActionPolygenicMonogenic/oligogenic
3.Pathotype SpecificityNon-Specific Specific
4.EfficiencyAgainst all races Against specific races
5.EffectivityNectrophs Biotrophs
6.Stage Of ExpressionIncreases with maturitySame from seedling to maturity
7.Chance Of EpidemicLess/MinimalPresent


Let's Discuss these points in detail:-

1.Nature Of Gene Action


➡️Horizontal resistance in plant is polygenic that means-It has many genes that can resistant against different virulent genes.It is specific.



➡️Vertical resistance is monogenic and sometimes oligogenic that means-It shows action against certain specific gene only.Its like gene for gene.


2.Pathotype Specificity


Pathotype is group of individuals that attacks some specific host. Some group attack one host while other group attack another host.


➡️Horizontal resistance is non-specific that means- It works against all kinds of pathogen. The resistance mechanism  activates in every group of pathogen that attacks the plant.


➡️Vertical resistance is specific that means-It works against specific pathotype. This resistance mechanism works for specific group but don't work for another group of pathogen.


3.Efficiency


➡️Horizontal resistance in plant shows efficiency  among all the races of pathogen. It works against all pathogens but cannot fully defend them. They slows down the damage caused by pathogens.



➡️Vertical resistance in plants shows action against specific race of pathogen. The effectiveness they show is very strong. They completely destroy the pathogens and saves the plants.


4.Effectivity


➡️Horizontal resistance is very effective against necrotrophs. This is because necrotrophs are the pathogens that kills the host tissue in advance of penetration. Thus-Horizontal resistance shows its mechanism when the pathogens are trying to kill the host tissue.



➡️Vertical resistance is very effective against biotrophs. This is because biotrophs are the pathogens that cannot live outside of living cells. In vertical resistance-There is a thing called Hypersensitivity. Due to this Hypersensitivity-When pathogen attacks plant vertical resistance cause the necrosis of its own plant cell. As the area attacked by pathogens undergo necrosis. That part becomes dead and biotrophs can't live outside living cell. That's why vertical resistance is effective against biotrophs.


5.Stage Of Expression


➡️Horizontal resistance in plants increases as the plant goes on maturing. This is durable form of resistance.


➡️Vertical resistance in plants is expressed from seedling to maturity in same power. It is less durable.



6.Chance Of Epidemic


➡️Horizontal resistance acts against all the races. That is why any changes or mutation in the race of plant doesn't affect the plants. There is minimal risk of inflection.There is no chance of epidemic.



➡️Vertical resistance acts only on certain group of specific race of pathogen. Any changes within the pathogen or any attack by new pathogen completely destroy the plant. There is a chance of epidemic.


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Let's take look a example to clear the concept of horizontal and vertical resistance:-

Horizontal And Vertical Resistance In Plants



Let us consider the 5 types of pathogen races.


The first bar diagram explains:- Vertical resistance is shown against the races 2,5 and 6. The resistance shown is complete that means the plants do not loss any production. They are completely healthy. Remaining races become completely susceptible.



The second bar diagram explains:- Horizontal Resistance acts against all the races. But-They can't completely oppose the races. They are mimizing the damage caused by pathogens. That's why the bar diagram is light green and height is half.



This is whole information on Horizontal And Vertical Resistance In Plants.

Also Read:-

➡️3g Cutting In Plants

➡️Glycolysis Steps With Enzymes And Energetics

➡️Mendal laws of inheritance

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