Question

Based on following statements, choose the correct combination.
(A). Plasmodiophora brassicae causes clubroot of crucifers
(B). Spongospora subterranean causes powdery scab of potato
(C). Polymyxa graminis is a vector for soilborne wheat mosaic virus
(D). Plasmodiophoromycota are biotrophic parasites

• A. (A), (B) and (D) only.
• B. (A), (C) and (D) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

Plasmodiophorids are notable for three things: they are soil-borne protists, they cause root galls/scabs, and they serve as vectors for major plant viruses (like SBWMV and Potato Mop-Top Virus).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The phylum Plasmodiophoromycota comprises a group of soil-borne, zoospore-producing protists.
These organisms are obligate, intracellular biotrophic parasites that infect plants, algae, and oomycetes, and often act as vectors for viruses.

Step 2: Detailed Explanation:
Let us analyze each statement:
Statement (A): Plasmodiophora brassicae is a classic plasmodiophorid that infects cruciferous crops (family Brassicaceae).
It causes abnormal hypertrophy and hyperplasia in root cells, leading to characteristic swelling or galling known as "clubroot."
Thus, Statement (A) is correct.
Statement (B): Spongospora subterranea is another well-known member of this phylum that infects potato tubers.
It produces galls on roots and scab-like lesions on tubers, a condition known as "powdery scab."
Thus, Statement (B) is correct.
Statement (C): Members of the Plasmodiophoromycota can vector viral pathogens during root infection.
Polymyxa graminis is a specialized root parasite of cereals that transmits several plant viruses, including Soil-borne wheat mosaic virus (SBWMV), from plant to plant via its resting spores.
Thus, Statement (C) is correct.
Statement (D): All plasmodiophorids are obligate intracellular biotrophic parasites.
They require living host cytoplasm to survive and complete their complex life cycle, which involves multinucleate plasmodia.
Thus, Statement (D) is correct.
All four statements are scientifically accurate, making (A), (B), (C), and (D) the correct combination.

Step 3: Final Answer:
The correct combination is (A), (B), (C) and (D).