Question

In which host-patho system does the Gene-for-Gene hypothesis operate?

• A. Host-Necrotrophic interaction
• B. Host-Saprophytic interaction
• C. Host-Biotrophic interaction
• D. Host-Obligate Saprophytic interaction

Hint:

Gene-for-Gene hypothesis:
- Operates in host-biotrophic interactions.
- For each resistance gene (R gene), there is an avirulence gene (Avr gene).
- Race-specific resistance.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
This question tests knowledge of the Gene-for-Gene hypothesis in plant-pathogen interactions.

Step 2: Detailed Explanation:
The Gene-for-Gene hypothesis operates in host-biotrophic (C) interactions.
It was proposed by Flor (1942) for the flax-rust interaction.
The hypothesis states that for each resistance gene in the host, there is a corresponding avirulence gene in the pathogen.
This interaction is race-specific and operates in biotrophic pathogens (which require living host tissue).
Other interactions:
- Necrotrophic pathogens (A): Cause cell death, do not follow the Gene-for-Gene hypothesis.
- Saprophytic (B): Pathogens that live on dead organic matter, not applicable.
- Obligate Saprophytic (D): Not a standard term.
Thus, the Gene-for-Gene hypothesis operates in host-biotrophic interactions.

Step 3: Final Answer:
Thus, the Gene-for-Gene hypothesis operates in host-biotrophic interaction, which corresponds to option (C).
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