bacteria

Question 1

What are the two major bacteria that cause bacterial spot or blight, and how are they transmitted?

Answer 1

The two major bacteria are Pseudomonas syringae and Xanthomonas campestris. They are transmitted by rainsplash, aerosols, contaminated seeds, and insects.

Question 2

What are three genera of bacteria responsible for vascular wilt?

Answer 2

Three genera are Clavibacter, Erwinia, and Ralstonia. Other genera include Curtobacterium and Pantoea.

Question 3

Which bacteria are the primary culprits for bacterial soft rots, and how do these diseases manifest?

Answer 3

Bacterial soft rots are caused by genera like Erwinia, Pseudomonas, Bacillus, and Clostridium. These diseases cause the plant tissue to become soft, watery, and slimy due to the breakdown of cell walls.

Question 4

What is the specific bacterium that causes bacterial galls, and what is its unique mode of infection?

Answer 4

Agrobacterium causes bacterial galls. It has a unique mode of infection where it transfers a segment of its own DNA (the Ti plasmid) into the plant’s chromosomes, inducing tumor-like growth.

Question 5

What are the two main bacteria that cause bacterial canker?

Answer 5

The two main bacteria are Pseudomonas syringae and Xanthomonas axononpodis.

Question 6

What is the primary pathogen responsible for bacterial scab?

Answer 6

The primary pathogen is Streptomyces, a unique type of filamentous bacterium.

Question 7

How is Xylella fastidiosa, a xylem-inhabiting bacterium, transmitted?

Answer 7

Xylella fastidiosa is transmitted by insects that feed on the xylem sap of plants, such as sharpshooters and spittlebugs.

Question 8

What is the bacterium associated with citrus greening disease, and which part of the plant does it inhabit?

Answer 8

Candidatus Liberibacter asiaticum is associated with citrus greening (Huanglongbing). It is a phloem-inhabiting fastidious bacterium.

Question 9

How are Phytoplasmas transmitted, and what are two diseases they cause?

Answer 9

Phytoplasmas are transmitted by phloem-feeding insects like leafhoppers and planthoppers. They cause diseases such as Aster yellows and Lethal yellowing in palms.

Question 10

What is the host range and transmission method for Erwinia amylovora, which causes fire blight?

Answer 10

Erwinia amylovora has a wide host range, primarily affecting Rosaceae family plants like apple, pear, and loquat. It is transmitted by rain, wind, and insects that feed on the sugary bacterial exudate.

Question 11

How is Ralstonia solanacearum transmitted, and what are some of its key hosts?

Answer 11

Ralstonia solanacearum is a soil-borne bacterium that enters through root wounds. It has a very wide host range, infecting over 310 plant species, including economically important crops like tomato, potato, eggplant, and banana.

Question 12

What is the primary host for Clavibacter michiganensis and how is it often transmitted?

Answer 12

The primary host for Clavibacter michiganensis is the tomato. It is transmitted through contaminated seeds, wounds, and natural openings.

Question 13

What are the primary hosts of Xanthomonas campestris pv. campestris?

Answer 13

This bacterium primarily infects cruciferous plants, such as cabbage, cauliflower, and broccoli, causing a disease called black rot

Question 14

What is the main mode of transmission for Agrobacterium tumefaciens?

Answer 14

Agrobacterium tumefaciens is a soil-borne bacterium that enters the plant through a wound

Question 15

What is the relationship between Erwinia and water in soft rot transmission?

Answer 15

Erwinia species, along with other soft rot bacteria, can be transmitted by water, as well as insects and infected plant material.

Question 16

What are phytoplasmas, and what do they lack compared to other bacteria?

Answer 16

Phytoplasmas are a type of Mollicutes, which are bacteria that lack a cell wall and cannot be cultured in a laboratory.

Question 17

Which bacteria cause a canker on citrus trees, and what is its transmission factor?

Answer 17

Xanthomonas axononpodis pv. citri causes citrus canker. It is transmitted locally by the Asian citrus leaf miner, wind, and rainfall.

Question 18

What is a unique characteristic of Streptomyces that distinguishes it from other plant pathogenic bacteria?

Answer 18

Streptomyces species are filamentous prokaryotes that produce spores for dispersal, a characteristic more commonly associated with fungi. They cause diseases of underground plant parts.

Question 19

What is the name of the disease caused by Xylella fastidiosa in grapes, and which part of the plant does it inhabit?

Answer 19

In grapes, Xylella fastidiosa causes Pierce’s disease. It inhabits the xylem vessels, disrupting water transport.

Question 20

What is the main insect vector for the Candidatus Liberibacter asiaticum bacterium that causes citrus greening?

Answer 20

The main insect vector is the Asian citrus psyllid.