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

Which of the following diseases are caused by fungal pathogens in barley? P. Kernel blight Q. Anthracnose R. Dwarf bunt S. Leaf rust T. Basal glume rot

  1. P and Q

  2. Q and R

  3. R and S

  4. P, R and T

  5. Q, R and S
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In apple, kernel blight disease is caused by bacteria- Pseudomonas syringae pv. syringae and basal glume rot is caused by bacteria-Pseudomonas syringae pv. atrofaciens. Anthracnose, dwarf bunt and leaf rust are caused by fungal pathogens-Collectotrichum cereale, Tilletia controversa and Puccinia hordei respectively, in apple.

Multiple choice

Which of the following statements is/are incorrect? P. Bunchy top disease of banana is caused by Pyricularia grisea. Q. Pseudomonas solanacearum causes Pseudostem heart rot disease in banana. R. Rhizome rot disease of banana is caused by Erwinia carotovora.

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

P. Bunchy top disease of banana is caused by Banana bunchy top virus (BBTV). Pyricularia grisea fungus causes Pitting disease in banana. Q. Pseudostem heart rot disease of banana is caused by Fusarium moniliforme. Pseudomonas solanacearum causes Bugtok disease in banana. R. Rhizome rot disease of banana is caused by Erwinia sp. like- E. carotovora, E. chrysanthemi. Hence, P and Q both the statements are false.

Multiple choice

Bt toxin is produced by B. thuringiensis in inactive form. Which of the following is responsible for the conversion of inactive Bt toxin into its active form?

  1. Acidic pH of the insect gut

  2. Alkaline pH of the insect gut

  3. Action of gut enzymes

  4. The microflora of the gut
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The alkaline digestive tract of the insects denatures the inactive toxin crystals making them soluble and thus, amenable to being cut with proteases found in the insect gut. This liberates the active toxin from the crystal, which then destroys the insect.