Question

Assertion (A): Trichoderma species are free living fungi that are very common in the root ecosystems.
Reason (R): They are effective bio-control agents of several plant pathogens.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Both statements are facts directly out of standard biology textbooks. Since the second fact does not provide the underlying cause for the first fact, select Option (B).

Answer 1

The Correct Option is B

Concept: Understanding the ecology and applications of biocontrol fungi:
• Species of the genus Trichoderma are free-living filamentous fungi commonly found in soil and root ecosystems (the rhizosphere).
• They act as efficient biocontrol agents through mechanisms like mycoparasitism, antibiotic production, and competing for nutrients against root pathogens.

Step 1: Analyze the Assertion statement.
Trichoderma species are free-living fungi that typically colonize the rhizosphere (root zone) of plants. This statement is entirely true.

Step 2: Analyze the Reason statement.
Trichoderma species are used as biocontrol agents to suppress various soil-borne plant pathogens. This statement is also entirely true.

Step 3: Evaluate the explanation link.
The fact that Trichoderma is a biocontrol agent does not explain why it is free-living or common in root ecosystems. Instead, its presence in the root zone is what allows it to function effectively as a biocontrol agent. Therefore, Reason (R) is not the correct explanation for Assertion (A). This aligns with Option (B).