MCAER PG CET 2026 PLANT PATHOLOGY

 

MCAER PG CET 2026
Plant Pathology Specialist Quiz

Time Remaining: 100s

1. The "Gene-for-Gene" hypothesis, which posits that for every resistance gene in the host there is a corresponding avirulence gene in the pathogen, was first demonstrated in:

A. Puccinia graminis tritici / Wheat B. Melampsora lini / Flax C. Phytophthora infestans / Potato D. Ustilago maydis / Maize

Explanation: H.H. Flor (1942) proposed this while working with Flax Rust (Melampsora lini).

2. [PYQ 2021] Which of the following chemical groups does 'Metalaxyl' belong to, and what is its specific mode of action?

A. Benzimidazoles - Tubulin polymerization B. Phenylamides - RNA Polymerase I inhibition C. Triazoles - Ergosterol biosynthesis D. Strobilurins - Mitochondrial respiration

Explanation: Metalaxyl is a systemic Phenylamide fungicide specifically effective against Oomycetes by inhibiting ribosomal RNA synthesis.

3. The term 'Quiescent infection' is most commonly associated with which post-harvest pathogen?

A. Colletotrichum gloeosporioides B. Rhizopus stolonifer C. Penicillium digitatum D. Aspergillus niger

Explanation: Quiescence is a dormant period in infection, typical of Anthracnose (Colletotrichum) in mango and papaya fruits.

4. In the context of bacterial cell walls, the 'Type III Secretion System' (T3SS) is crucial for:

A. Nutrient uptake from the soil B. Injecting effector proteins into host cells C. Binary fission regulation D. Flagellar movement only

Explanation: T3SS (the "injectisome") is used by Gram-negative bacteria like Pseudomonas and Xanthomonas to bypass plant defenses.

5. [PYQ 2023] Which viral genome is uniquely known to undergo 'Reverse Transcription' during replication despite being a DNA virus?

A. Geminiviridae B. Caulimoviridae C. Potyviridae D. Bromoviridae

Explanation: Caulimoviruses (like Cauliflower Mosaic Virus) are pararetroviruses; they have dsDNA but replicate via an RNA intermediate.

6. A 'Holomorph' in mycology refers to:

A. Only the asexual stage B. Only the sexual stage C. The whole fungus (Anamorph + Teleomorph) D. The fossilized remains of a fungus

Explanation: Holomorph = Teleomorph (sexual) + Anamorph (asexual).

7. The 'Robinson's Concept' of vertical and horizontal resistance defines vertical resistance as:

A. Polygenic and race-non-specific B. Oligogenic and race-specific C. Environmentally stable resistance D. Tolerance rather than immunity

Explanation: Vertical resistance (Van der Plank) is usually controlled by one or few genes and is effective against specific races.

8. Which of the following is an example of a 'Phanerogamic Total Stem Parasite'?

A. Loranthus B. Striga C. Cuscuta D. Orobanche

Explanation: Cuscuta (Dodder) is a total stem parasite. (Orobanche is total root, Striga is partial root).

9. 'Kranz Anatomy' is disrupted in sugarcane by which pathogen leading to leaf thinning?

A. Ustilago scitaminea B. Grassy Shoot Phytoplasma C. Colletotrichum falcatum D. Xanthomonas albilineans

Explanation: Grassy Shoot Disease (GSD) caused by Phytoplasma leads to severe chlorosis and stunting, affecting photosynthetic structures.

10. The first bacterial disease discovered was:

A. Citrus Canker B. Fire blight of Pear C. Crown Gall D. Black rot of Crucifers

Explanation: T.J. Burrill in 1882 proved that Fire Blight of Pear/Apple was caused by Erwinia amylovora.

Review the explanations above for better understanding.