Biology

Microbes and Plant Diseases

1,118 Questions

Microbes and plant diseases examine the role of fungi, bacteria, and viruses in causing infections in plants and humans. Topics cover symbiotic associations like mycorrhiza, fungal structures, and specific agricultural pathogens. Practice these biology questions to master microbiology concepts for upcoming competitive examinations.

Fungal associationsPlant pathogensMicrobial structuresBacterial infections

Microbes and Plant Diseases Questions

Multiple choice

Identify the false statement(s).

A. Tropical cotton rust of cotton is caused by Phakopsora gossypii. B. Puccinia striiformis causes scald disease in barley. C. The causative agent for cottony snow mold of wheat is Tilletia controversa.

  1. Only A

  2. Only B

  3. Only C

  4. A and B

  5. B and C
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The causative fungal agent for stripe yellow rust of barley is Puccinia striiformis. Scald disease of barley is caused by the fungus Rhynchosporium secalis. Cottony snow mold disease of wheat is caused by the fungus Coprinus psychromorbidus. Dwarf bunt of wheat is caused by Tilletia controversa. Hence, the statements B and C both are false.

Multiple choice

Which of the following pairs is not one of the fungal diseases, caused by pathogens in sugarcane?

  1. Yellow leaf spot - Cercosporidium kopkei

  2. Black stripe - Peronosclerospora sacchari

  3. Stem canker - Cytospora sacchari

  4. Red rot - Cercosporidium falcatum

  5. Brown leaf spot - Cercosporidium longipes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Black stripe disease in sugarcane is caused by Cercospora atrofiliformis. Peronosclerospora sacchari fungus causes downy mildew disease in sugarcane.

Multiple choice

Match the fungal diseases in Group-I with causative pathogens in Group-II.

 
Group-I
Group-II
P. Leaf spot of cherries and palms 1. Claviceps purpurea
Q. Ergot of barley 2. Taphrina deformans
R. Citrus greasy leaf spot 3. Blueriella sp.
S. Leaf curl of peach and apricot 4. Drechslera teres
5. Mycosphaerella citri

  1. P - 3, Q - 1, R - 5, S - 2

  2. P - 5, Q - 1, R - 4, S - 2

  3. P - 3, Q - 4, R - 5, S - 2

  4. P - 2, Q - 3, R - 4, S - 1

  5. P - 1, Q - 4, R - 5, S - 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Leaf spot of cherries and palms is caused by Blueriella sp. The causative agent for ergot disease in barley is Claviceps purpurea. Citrus greasy leaf spot is caused by the fungus Mycosphaerella citri. Banana leaf spot is caused by Mycosphaerella musicosa. Taphrina deformans causes leaf curl of peach and apricot. Hence, the correct sequence of codes is P-3, Q-1, R-5, S-2.

Multiple choice

Match the diseases in List-A with causative fungal pathogens in List-B and select the correct answer using the codes given below.

List-A
List-B
A. Cottony snow mold of wheat 1. Sclerotium rolfsii
B. White leaf spot of crucifer 2. Coprinus psychromorbidus
C. Hull rot of almond 3. Rhizopus sp.
D. Southern blight of cotton 4. Pseudocercosporella capsellae

  1. A - 2, B - 4, C - 3, D - 1

  2. A - 3, B - 1, C - 4, D - 2

  3. A - 2, B - 4, C - 1, D - 3

  4. A - 1, B - 3, C - 2, D - 4

  5. A - 2, B - 1, C - 3, D - 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cottony snow mold of wheat is caused by the fungus, Coprinus psychromorbidus. White leaf spot of crucifer is caused by Pseudocercosporella capsellae. Hull rot disease of almond is mainly caused by Rhizopus sp. Southern blight of cotton is caused by the fungal pathogen, Sclerotium rolfsii. Hence, the sequence of codes A-2, B-4, C-3, D-1 is correct.

Multiple choice

A phage sensitive strain of E. coli is grown in the environment containig DNA from phage resistant bacteria. After incubation, the sensitive strain becomes resistant. Which of the following mechanisms is responsible for this event?

  1. Transduction

  2. Transformation

  3. Conjugation

  4. Replication

  5. Translation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Transformation is genetic alteration of a cell resulting from the direct uptake, incorporation and expression of exogenous genetic material (exogenous DNA) from its surroundings and taken up through the cell membrane(s).

Multiple choice

What must happen to bacteriophage prior to infecting a bacterium?

  1. It should reproduce to make multiple copies of the phage chromosome.

  2. It should integrate its genome into the bacterial chromosome.

  3. It should penetrate the bacterial cell wall completely.

  4. It should attach to a receptor on the bacterial cell membrane.

  5. It should undergo shrinkage in its size.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The first step in the infection of a host is attachment of the phage tail to a specific receptor on the host cell membrane. The capsid on the bacteriophage does not enter the host cell.

Multiple choice

The fungal body is known as _______.

  1. holocarps

  2. eucarps

  3. mycelium

  4. mycorrhiza

  5. fruiting body
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mycelium (plural mycelia) is the vegetative part of a fungus consisting of a mass of branching, thread-like hyphae.