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 botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Crown Gall is due to

  1. Agrobacterium

  2. Mycobacterium

  3. Clostridium

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

Crown gall disease is a plant disease that is caused by the bacterium Agrobacterium tumefaciens. It results in the overgrowth appearing as knobbly swellings or galls on stems, roots, trunks, and branches. It affects mostly woody shrubs and herbaceous plants like grapes, raspberries, blackberries, and roses.

Thus, the correct answer is 'Agrobacterium.'

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Agrobacterium tumefaciens causes

  1. Wilt

  2. Damping off

  3. Rust

  4. Crown gall
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Crown gall disease is a plant disease that is caused by the bacterium Agrobacterium tumefaciens. It results in the overgrowth appearing as knobbly swellings or galls on stems, roots, trunks, and branches. It affects mostly woody shrubs and herbaceous plants like grapes, raspberries, blackberries, and roses.

Thus, the correct answer is 'Crown gall.'

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Grown gall disease of plants is caused by

  1. Ti-plasmid

  2. Pi-Plasmid

  3. Virus

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

Crown gall disease is a plant disease that is caused by the bacterium Agrobacterium tumefaciens. Ti plasmid is essential to cause disease. It transfers bacterial DNA into the host cell where it incorporates itself into the host genome. It results in the overgrowth appearing as knobbly swellings or galls on stems, roots, trunks, and branches. It affects mostly woody shrubs and herbaceous plants like grapes, raspberries, blackberries, and roses.

Thus, the correct answer is 'Ti-plasmid.'

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Xanthomonas citri is related to

  1. Disease in Xanthium

  2. Xanthophyceae

  3. A virus

  4. Citrus canker
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Citrus canker is a disease that is caused by the bacterium Xanthomonas axonopodis. It affects the Citrus species of fruits such as lime, oranges, grapefruit. It results in the lesions on the leaves, stems, fruit and other parts of the citrus plants.

Thus, the correct answer is 'Citrus canker.' 

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Which one causes blight disease of rice?

  1. Xanthomonas oryzae

  2. Pseudomonas oryzae

  3. Erwinia oryzae

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

Blight disease of Rice is a deadly disease that affects the cultivated rice. It is caused by bacteria Xanthomonas oryzae. It causes wilting of seedlings and yellowing and drying of leaves.

Thus, the correct answer is 'Xanthomonas oryzae.'

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Little leaf disease and plant yellows are caused by

  1. Halobacterium

  2. Mycoplasma

  3. Bdellovibrios

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

Little leaf disease is a disease that affects brinjal. Symptoms include reduction in leaf size and rosette like appearance. It is transmitted by leafhopper. It is caused by Mycoplasma. Apart from this, Mycoplasma also causes witches' broom disease and plant yellows diseases.

Thus, the correct answer is 'Mycoplasma.'

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Citrus canker is caused by

  1. Bacteria

  2. Virus

  3. Fungus

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

Citrus canker is a disease that is caused by the bacterium Xanthomonas axonopodis. It affects the Citrus species of fruits such as lime, oranges, grapefruit. It results in the lesions on the leaves, stems, fruit and other parts of the citrus plants.

Thus, the correct answer is 'Bacteria.' 

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Which among the following is a bacterial disease?

  1. Rust of Tea

  2. Red rot of Sugarcane

  3. Citrus canker

  4. Late blight of Potato
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rust of Tea is also called as red rust disease. It is caused by algae Cephaleuros parasiticus Karst. It affects the tea plant. Red rot is a disease that affects the sugarcane plant. It is caused by fungus Glomerella tucumanensis. Citrus canker is a bacterial disease affecting Citrus species caused by the Xanthomonas axonopodis. It affects Citrus species like lime, orange. Late blight is an infection caused by fungus Phytophthora infestans. It affects potato and tomato.

Thus, the correct answer is 'Citrus canker.'

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

A plant disease which is not caused by a fungus is

  1. Red rot of Sugarcane

  2. Late blight of Potato

  3. Black rot of crucifers

  4. Brown rust of wheat
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Red rot disease is caused by the fungus Glomerella tucumanensis. It produces a structure called as acervuli. This results in profuse sporulation. Late blight of Potato is caused by fungus Phytophthora infestans. It infects and destroys the leaves, stems, fruits, tubers of potato and tomato plants. Black rot of crucifers is caused by bacterium Xanthomonas campestris. It results in dark brown discoloration of the leaves of fruit and vegetables. Wheat leaf rust is a disease caused by fungus Puccinia triticina. It affects wheat, barley and rye stems, leaves and grains. 

Thus, the correct answer is 'Black rot of crucifers.'

Multiple choice zoology diversity in living world hemichordata phylum hemichordata chordates and hemichordates

Many acorn worms are known to produce

  1. Proteins

  2. Casein

  3. Phenol

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

Acorn worms is a hemichordate. They are closely related to echinoderms. They are solitary worm-shaped organisms. They can be traced in burrows and are deposit feeders, but some species are pharyngeal filter feeders. Many are well known for their production and accumulation of various halogenated phenols and pyrroles. 

So, the correct answer is option C.