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

Which of the following features is similar in both monerans and fungi?

  1. Structure of fruiting body

  2. Absorptive heterotrophy

  3. Cellular structure

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

Both monerans (bacteria) and fungi are absorptive heterotrophs - they absorb nutrients from their environment rather than ingesting food. This nutritional mode is the key similarity between these two groups, despite their many other differences.

Multiple choice

The cell wall of fungi is made up of

  1. chitin

  2. cellulose

  3. peptin

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

Fungal cell walls are composed of chitin, a tough polysaccharide also found in insect exoskeletons. This distinguishes fungi from plants (cellulose cell walls) and bacteria (peptidoglycan cell walls). Option C's 'peptin' appears to be a typo for pectin.

Multiple choice

Mushroom is a/an

  1. saprophyte

  2. facultative parasite

  3. autotroph

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

Mushroom is a saprophyte.

Multiple choice

What is the mode of nutrition of Rhizopus, Yeast and Pencillium?

  1. Parasitic

  2. Saprophytic

  3. Symbiotic

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

Rhizopus, yeast, and Penicillium are fungi that obtain nutrition by secreting enzymes onto dead organic matter and absorbing the broken-down products - this is saprophytic nutrition. Parasites feed on living hosts, symbionts have mutual relationships, and autotrophs produce their own food.

Multiple choice

Which of the following is saprophytic in nutrition?

  1. Fungi

  2. Virus

  3. Algae

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

Fungi obtain nutrition by absorbing dissolved organic matter from dead substrates - the saprophytic mode. Viruses are non-living, algae are photosynthetic autotrophs, and cyanobacteria are also photosynthetic - none share the fungal absorptive heterotrophic nutrition.

Multiple choice

In carrot, Sclerotinia minor causes the disease

  1. crator rot

  2. crown rot

  3. leaf blight

  4. violet root rot

  5. cottony rot
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Correct answer. In carrot, Cottony rot disease is caused by the fungal species- Sclerotinia sp. (S. minor, S. Sclerotiarum).

Multiple choice

Which of the following diseases are caused by fungal pathogens only 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

This option is correct because 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

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

 
List - A List - B
A. Perennial canker 1. Grovesinia pyramidalis
B. Fruit decay 2. Neofabraea perennans
C. Pink mold rot 3. Trichothecius roseum
D. Zonate leaf spot 4. Valsa ceratosperma
5. Phomopsis mali

  1. A - 2, B - 4, C - 3, D - 5

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

  3. A - 2, B - 5, C - 3, D - 1

  4. A - 4, B - 5, C - 1, D - 2

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

This option is correct because in apple, Perennia canker disease is caused by Neofabraea perennans, Fruit decay is caused by Phomopsis mali, Pink mold rot disease is caused by Trichothecius roseum and Zonate leaf spot disease is caused by Grovesinia pyramidalis.

Multiple choice

Which of the following statements is/are false?

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, both P and Q statements are false.

Multiple choice

Which of the following statements is/are true?

P. Spot anthracnose disease of rose is caused by Sphaceloma rosarum. Q. Bordeaux mixture was introduced by Pierre-Marie-Alexis Millardet in 1885. R. Plant pathogenic disorders can be controlled by crop rotation.

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

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

Correct answer. In rose, Spot anthracnose disease is caused by the fungus- Sphaceloma rosarum. In the 19th century, several outbreaks of vine diseases occurred among the Vitis vinifera vines of the classicial European wine regions. After the downy mildew had struck, botany professor Pierre-Marie-Alexis Millardet of the University of Bordeaux studied the disease in vineyards of the Bordeaux region. In 1885, Millardet published your findings on mildew of grapes and introduced Bordeaux mixture to control downy mildew of grapes. Crop rotation may be an effective means to prevent a parasitic population from becoming well-established, as an organism affecting leaves would be starved when the leafy crop is replaced by a tuberous type, etc. Other means to undermine parasites without attacking them directly may exist.