Question

Biotrophs are important groups of plant pathogens.
A. They need live host to complete their life cycle
B. They can be cultured on artificial media
C. They do not harm their host
D. They cause sign instead of symptoms
E. Magnaporthe is a biotroph
Choose the correct answer from the options given below:

• A. A, C, D only
• B. A, B, C only
• C. B, C, D only
• D. B, C, E only

Hint:

Biotrophs require living hosts, do not cause immediate cell death, and produce macroscopic fungal signs.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Obligate biotrophs maintain delicate physiological relationships with living host plant cells.

Step 2: Detailed Explanation:
Evaluating the biological properties of biotrophic pathogens:
- Statement A is TRUE: Biotrophs (e.g., rusts, powdery mildews, downy mildews) strictly require living host protoplasm to complete their parasitic life cycle.
- Statement B is FALSE: Pure biotrophs cannot be cultured on artificial synthetic media.
- Statement C is TRUE (in comparative context): Biotrophs do not immediately kill or destroy host cells, establishing specialized haustoria to feed without inducing rapid tissue necrosis.
- Statement D is TRUE: Biotrophs predominantly produce prominent macroscopic pathogen structures/signs (powdery mildew white mycelium, rust pustules) on intact green host surfaces.
- Statement E is FALSE: Magnaporthe oryzae is a hemibiotroph (initial biotrophic phase followed by destructive necrotrophy).

Step 3: Final Answer:
Hence, statements A, C, and D only represent the characteristic properties.