Biology

Microbes and Plant Diseases

1,145 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

Bacterial fruit blotch (BFB) affects cucurbit plants around the world. Which of the following bacteria is implicated in this disease?

  1. Acidovorax cattleyae

  2. Acidovorax citrulli

  3. Acidovorax konjaci

  4. Acidovorax avenae ssp. avenae
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Acidovorax citrulli infection can result in bacterial fruit blotch (BFB). Lesions are necrotic and may be located near veins. The fruit eventually decays and cracks when the pathogen causes necrosis.

Multiple choice

Dickeya dadantii causes necrosis, blight and soft rot of several different ornamental and horticultural host plants. Which of the following enzymes does it contain to macerate and break down the plant material?

  1. Pectinase

  2. Cellulase

  3. Hyaluronidase

  4. Oxidase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Dickeya dadantii contains many pectinases that are able to macerate and break down the plant cell wall material. This exposed part of the plant releases nutrients that can facilitate bacterial growth.

Multiple choice

Which of the following bacteria causes stunting and wilting of alfalfa?

  1. Clavibacter michiganensis subsp. insidiosus

  2. Clavibacter michiganensis subsp. tesselarius

  3. Clavibacter michiganensis subsp. nebraskensis

  4. Clavibacter michiganensis subsp. michiganensis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Clavibacter michiganensis subsp. insidiosus causes wilting and stunting in alfalfa.

Multiple choice

Ratoon stunting disease is associated with which of the following pairs of pathogen and plant?

  1. Leifsonia xyli xyli - bermuda grass

  2. Leifsonia xyli cynodontis - bermuda grass

  3. Leifsonia xyli cynodontis - sugarcane plant

  4. Leifsonia xyli xyli - sugarcane plant
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Leifsonia xyli subsp. xyli is a small, fastidious, Gram-positive and coryneform bacterium that is associated with the ratoon stunting disease, a major worldwide disease of sugarcane. Infected plants show reduced cane diameter and shortening of the inter-nodes.

Multiple choice

Blackleg of potato is the typical blackening and decay of the lower stem portion of plant. Which of the following bacteria causes blackleg of potato?

  1. Pectobacterium carotovorum

  2. Pectobacterium betavasculorum

  3. Pectobacterium atrosepticum

  4. Pectobacterium chrysanthemi
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Blackleg in potatoes is caused by Pectobacterium atrosepticum. It results in stunting, wilting, chlorosis of leaves, necrosis of several tissues, a decline in yield and the death of the potato plant.

Multiple choice

Which of the following plant pathogens can be commercially exploited to obtain 6-Amino penicillanic acid (6-APA)?

  1. Pseudomonas citronellolis

  2. Pseudomonas cichorii

  3. Pseudomonas asplenii

  4. Pseudomonas marginalis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pseudomonas cichorii is a Gram-negative soil bacterium that is pathogenic to lettuce, celery and chrysanthemum crops. It produces 6-aminopenicillanic acid that forms the core of penicillin. It shows the possibility of being commercially exploited for obtaining 6-Amino penicillanic acid.