Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Oomycetes pathogens need high moisture for their dissemination.
Reason (R) : Oomycetes pathogens do produce motile spores during their life cycle.
In light of the above statements, choose the correct answer from the options given below.

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

Hint:

To identify whether the Reason explains the Assertion, connect them using the word "because":
"Oomycete pathogens require high moisture for dispersal BECAUSE they produce motile zoospores that must swim through water to reach and infect host plants."
This reads as a logical, scientifically correct explanation.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
This question focuses on the biological and environmental requirements for the dispersal of oomycete plant pathogens.
Oomycetes (such as *Phytophthora* and *Pythium*) are fungi-like protists whose life cycles are closely linked to wet environments.

Step 2: Detailed Explanation:
Let us analyze the assertion and reason:
Assertion (A): "Oomycetes pathogens need high moisture for their dissemination."
This statement is correct.
Oomycete pathogens (such as those causing downy mildews, late blight, and damping-off) require highly humid conditions, free water, or waterlogged soils to disperse and infect new host plants.
Dry conditions inhibit their spread, while wet seasons often trigger explosive epidemics.
Reason (R): "Oomycetes pathogens do produce motile spores during their life cycle."
This statement is correct.
During their asexual reproduction phase, oomycetes produce specialized structures called sporangia.
In the presence of free water or high moisture, these sporangia germinate to release motile, biflagellated asexual spores called zoospores.
These zoospores have a tinsel flagellum and a whiplash flagellum, allowing them to swim through water films on leaves or waterlogged soil pores to locate and infect host tissues.
Because these spores require water to swim and disperse, the pathogen depends completely on high moisture or free water for its dissemination.
Therefore, (R) is the direct biological explanation for (A).

Step 3: Final Answer:
Both (A) and (R) are true, and (R) is the correct explanation of (A).
This corresponds to Option (1).