Chapter 3 Self-test questions

. How many phyla of bacteria contain plant pathogens?

30

3

10

1

. What specific feature characterizes phytoplasmas and spiroplasmas in the Tenericutes phylum of bacteria?

They are gram positive bacteria.

They are gram negative bacteria.

They do not have a cell wall.

They are single-celled rod-shaped bacilli.

. Which of the following plants are not affected by Erwinia amylovora, the bacterium that causes fire blight disease?

Apple and pear.

Pyracantha and Cotoneaster.

Hawthorn and firethorn.

Raspberry and blackberry.

. Which of the following is not considered an important entry point for infection by Erwinia amylovora?

Natural openings in the floral cup.

Natural wounds created by lateral root formation.

Open stomata in leaves.

Wounds created by heavy rain, hail or insect feeding.

. Which of the following methods allows the most accurate classification and identification of plant pathogenic bacteria?

Genome sequencing.

Fatty-acid profiling.

Pathogenicity testing.

Microscopic examination of cell morphology.

. Which conditions tend to favour infection of plants by plant pathogenic bacteria?

Cool dry conditions.

Warm humid conditions.

Warm dry conditions.

Cool humid conditions.

. Which of the following pathogenicity factors allow bacteria to cause rotting symptoms in plant disease?

Toxins.

Growth hormones.

Extracellular enzymes.

Extracellular polysaccharides.

. Which of the following bacteria causes crown gall disease of many host plant species?

Ralstonia solanacearum.

Rhizobium leguminosarum.

Ti plasmid-carrying strains of Rhizobium radiobacter.

Ri plasmid-carrying strains of Rhizobium radiobacter.

. Which of the following pathways of spread is most likely to lead to long distance international dispersal of plant pathogenic bacteria?

Trade of infected seeds.

Rain-splash and wind-blown aerosols.

Insect transmission.

Use of contaminated pruning tools.

.

What is the most effective way to control plant pathogenic bacteria?

Use chemical control.

Grow resistant varieties.

Remove and burn diseased plants.

Prevent their introduction in the first place.

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