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

The fungi responsible for the Great Irish Famine is

  1. the Ustilago

  2. the Rhizoctonia

  3. the Pythium

  4. the Phytophthora

  5. the Xanthomonas
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Phytophthora spp. are mostly pathogens of dicotyledons and are relatively host-specific parasites. Many species of Phytophthora are plant pathogens of considerable economic importance. Phytophthora infestans was the infective agent of the potato blight that caused the Great Irish Famine.

Multiple choice

Which of the following systems is used for searching NCBI data?

  1. Entrez

  2. SRS

  3. Google

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

Entrez is NCBI's integrated search and retrieval system that provides access to nucleotide sequences, protein sequences, structures, genomes, literature, and other databases. SRS is a different database system, Google is a general search engine, and BankIt is a sequence submission tool.

Multiple choice

There exists a close association between the alga and the fungus within a lichen. The fungus

  1. provides food for the alga

  2. provides protection, anchorage and absorption for the alga

  3. fixes the atmospheric nitrogen for the alga

  4. releases oxygen for the alga
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 There exists a close association between the alga and the fungus within a lichen. The fungus provides protection, anchorage and absorption for the alga.This association is known as symbiosis.

Multiple choice

The spores are released in the air by

  1. breaking of the wall of sporangium

  2. breaking up of whole of the parent body

  3. vigorous shaking of the sporangium

  4. breaking of the wall of hyphae
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Spores are released into the air when the sporangium wall breaks open. The sporangium is a specialized structure that contains spores. When mature, the sporangium ruptures, releasing numerous spores that can be dispersed by wind to new locations for germination.

Multiple choice

Which fungus is responsible for the disease athlete's foot?

  1. Cryptococcus

  2. Sporothrix schenckii

  3. Trichophyton rubrum

  4. Tinea versicolor

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

Athlete's foot, also known as ringworm of the foot, or tinea pedis, is a fungal infection of the skin that causes scaling, flaking and itch of affected areas. It is caused by fungi in the genus Trichophyton. The fungus genus Trichophyton is characterized by the development of both smooth walled macro and microconidia. Trichophyton rubrum is a fungus that is the most common cause of athlete's foot, jock itch and ringworm.

Multiple choice

Which of the following pairs is incorrectly matched?

  1. Whisker mold - Penicillium ulaiense

  2. Mal secco - Phoma tracheiphila

  3. Blue mold - Penicillium italicum

  4. Green fruit mold - Mucor paronychia

  5. Rootlet rot - Pythium rostratum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Penicillium digitatum causes Green fruit mold in citrus. Mucor fruit rot is caused by Mucor sp. (Mucor paronychia, Mucor racemosus).

Multiple choice

Match the following:

 
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.

Multiple choice

The causative fungal agent for ‘Halo spot’ disease in barley is

  1. Pyrenophora teres f. teres

  2. Rhynchosporium secalis

  3. Blumeria graminis f. sp. hordei

  4. Puccinia hordei

  5. Pseudoseptoria stomaticola
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In Barley, white to tan, small, semi-rectangular spots or blotches with a dark brown edge aligned along the veins of the leaf blade is known as Halo spot disease. The causative fungus of the said disease is Pseudoseptoria stomaticola.

Multiple choice

Which of the following statements is/are false?

P. Leaf streak disease of maize is caused by Stenocarpella macrospora. Q. Stem rot of potato is caused by Sclerotium rolfsii. R. Athelia arachnoidea causes crater rot in carrot. S. Cercospora brachypus causes noble rot disease in grapes.

  1. Only P

  2. P and Q

  3. Q and R

  4. R and S

  5. Only S
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

P. Leaf streak disease is caused by the fungus, Stenocarpella macrospora in maize. Q. The causing fungal pathogen for stem rot of potato is Sclerotium rolfsii. R. Athelia arachnoidea causes crater rot in carrot. S. Grey rot or noble rot disease is caused by Botrytis cinerea in grapes. Mycosphaerella angulata and Cercospora brachypus cause angular leaf spot in grapes. Hence, only statement S is false.