Types of Bacteria Infecting Plants
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Questions and Answers

How does Xanthomonas campestris affect plants?

By producing large amounts of polysaccharides that block the xylem vessels.

What is the main group of bacteria that cause plant disease mentioned in the text?

Proteobacteria

Which bacterial species associated with stomach ulcers is mentioned in the text?

Helicobacter pylori

How are Mycoplasma-like species of bacteria introduced into plants?

<p>By insects such as aphids that suck plant sap.</p> Signup and view all the answers

What useful compounds do some species of Proteobacteria in soil form for plants?

<p>Nitrogen compounds</p> Signup and view all the answers

What is the thickener obtained from the polysaccharides produced by Xanthomonas campestris?

<p>Xanthan gum</p> Signup and view all the answers

What are some measures adopted for plant protection against bacterial diseases?

<p>Seed treatment, treatment of vegetative propagation material, foliar sprays, therapy, immunisation, disease forecasting</p> Signup and view all the answers

Give an example of seed treatment for protection against plant diseases.

<p>0.02% streptocycline treatment of seed tubers of potato against brown rot disease</p> Signup and view all the answers

How are resistant varieties of plants evolved for protection against bacterial pathogens?

<p>Selection, breeding, and other methods are used to evolve resistant varieties</p> Signup and view all the answers

What is the role of therapy in plant protection against diseases?

<p>Pencillin and vancomycin are used for disintegration of the crow gall</p> Signup and view all the answers

How does disease forecasting assist in managing bacterial diseases in plants?

<p>It helps in timely and economic management based on observations and prediction models</p> Signup and view all the answers

Explain the process of immunisation for plant protection against bacterial pathogens.

<p>Screening for resistance sources under artificial conditions and evolving resistant varieties</p> Signup and view all the answers

What is the difference between a sign and a symptom of plant disease?

<p>A sign of plant disease is physical evidence of the pathogen, such as a bacterial exudate or fungal growth. A symptom of plant disease is a visible effect of the disease on the plant, such as a change in color, shape, or function.</p> Signup and view all the answers

Describe the symptoms of bacterial canker on tomato, capsicum, and chilli plants.

<p>Symptoms of bacterial canker on tomato, capsicum, and chilli plants include seedlings dying, older plants wilting and dying, leaves turning yellow and wilting on one side, and the development of cankers on the stems and fruit. The tissue inside the stems also becomes discolored.</p> Signup and view all the answers

What are the symptoms of bacterial soft rot on a wide range of vegetable crops?

<p>The symptoms of bacterial soft rot include a wet, slimy, and soft rot that affects any part of the vegetable crop, including heads, curds, edible roots, stems, and leaves. The affected areas may also have a disagreeable odor.</p> Signup and view all the answers

Describe the symptoms of bacterial leaf spot/bacterial spot on lettuce, tomatoes, capsicums, and cucurbits.

<p>On lettuce, the symptoms include large brown to black circular areas that start as small translucent spots, usually on the outer leaves. On tomatoes and capsicums, the symptoms are greasy spots on leaves and stems that go from tan to black, and the fruit may have circular spots with a central scab. On cucurbits, the symptoms begin as small water-soaked/greasy spots on the underside of leaves with corresponding yellowing on the upper side, and the fruit may produce a light-brown ooze from water-soaked markings.</p> Signup and view all the answers

What are the symptoms of bacterial wilt on potato, tomato, capsicum, and eggplant plants?

<p>The symptoms of bacterial wilt include wilting, yellowing, and stunting of the plants, but they may also wilt rapidly and die without any spotting or yellowing. The vascular tissue appears brown and water-soaked, and a white ooze appears when pressure is applied to affected tubers or stems.</p> Signup and view all the answers

Describe the symptoms of bacterial leaf spot/bacterial spot/bacterial blight on beet, spring onions, leeks, rocket, and coriander.

<p>On beet, the symptoms are irregular, round leaf spots with a grey center surrounded by a purple margin. On spring onions/shallots, the symptoms are pale yellow to light-brown lesions with a water-soaked appearance around the margins, and the outer leaves wither and die while the youngest leaf turns lemon to light-green. On leeks, the symptoms are brown streaking on the shank.</p> Signup and view all the answers

What are some general principles of managing bacterial diseases?

<p>Exclusion, eradication, plant sanitation</p> Signup and view all the answers

Give an example of a disease that was successfully managed through eradication.

<p>Citrus canker in Florida, USA during 1914-1927</p> Signup and view all the answers

How can crop rotation with cereals help in managing wilt of tobacco?

<p>Reduces the intensity of the disease</p> Signup and view all the answers

What cultural measure is recommended against the potato wilt?

<p>Sterilization of the cutting knife by flame or by 0.1% KMNO4 solution</p> Signup and view all the answers

What is a recommended seed treatment practice to manage bacterial blight of cotton?

<p>Delinting of cotton seed with concentrated sulphuric acid</p> Signup and view all the answers

How can plant sanitation help prevent the spread of bacterial blight of cotton?

<p>Removing dead plant parts and protecting cut surfaces with bactericides</p> Signup and view all the answers

How do aphids obtain sugars from plants?

<p>Aphids use needle-like mouth parts to puncture plant stems and tap directly into the phloem vessels, which transport sugars.</p> Signup and view all the answers

What role do Mycoplasma bacteria play in plant diseases caused by aphids?

<p>The Mycoplasma bacteria grow inside aphids and are introduced into plants when the aphids feed, acting as an efficient means of transmission.</p> Signup and view all the answers

What are some common symptoms of plant diseases caused by bacteria?

<p>Common symptoms include leaf discoloration, absence or abnormal coloration of flowers, and general weakening of the plant.</p> Signup and view all the answers

How can bacteria that cause plant diseases survive in nature?

<p>Bacteria can survive in plant debris, seeds, soil, water, on inanimate objects, inside insects, and in association with perennial host plants.</p> Signup and view all the answers

What role does temperature play in the dissemination of certain bacterial plant diseases?

<p>Some bacterial diseases require specific temperature conditions to progress, e.g. Pseudomonas syringae below 22°C and Xanthomonas campestris above 22°C on dry bean plants.</p> Signup and view all the answers

How can bacteria gain entry into plants to cause infection?

<p>Bacteria can enter through natural plant openings like stomata, wounds or abrasions, by being sucked in, or by being introduced by insect vectors during feeding.</p> Signup and view all the answers

Which of the following bacteria is mentioned as causing cholera in humans?

<p>Vibrio cholerae (A)</p> Signup and view all the answers

What compound produced by Xanthomonas campestris is used as a thickener in the food industry?

<p>Xanthan gum (C)</p> Signup and view all the answers

How does Xanthomonas campestris affect plants from the Brassica and Arabidopsis groups?

<p>It causes black rot by blocking xylem vessels (A)</p> Signup and view all the answers

How are Mycoplasma-like species of bacteria introduced into plants?

<p>By insects that suck plant sap, such as aphids (B)</p> Signup and view all the answers

What group of bacteria is mentioned as having species that fix nitrogen from the air, forming useful compounds for plants?

<p>Proteobacteria (B)</p> Signup and view all the answers

Which of the following is NOT a symptom of black rot caused by Xanthomonas campestris, as described in the text?

<p>Stunted growth and leaf curling (B)</p> Signup and view all the answers

What is the purpose of foliar sprays with Bordeaux mixture and copperoxy – chloride?

<p>To protect against leaf spots and blights (C)</p> Signup and view all the answers

What is the main focus of immunisation in plant protection against bacterial pathogens?

<p>Developing resistance sources for pathogens (C)</p> Signup and view all the answers

What is a crucial aspect of disease forecasting according to the text?

<p>Using bacteriophage population as an index (D)</p> Signup and view all the answers

Which method is suggested for evolving resistant varieties against bacterial blight disease?

<p>Breeding for desirable traits (D)</p> Signup and view all the answers

How do antibacterial chemicals in seed treatment contribute to plant protection?

<p>Protecting against bacterial diseases (C)</p> Signup and view all the answers

Which substance is mentioned for the treatment of seed tubers of potato against brown rot disease?

<p>Streptomycin sulphate (A)</p> Signup and view all the answers

What is one of the general principles mentioned in the text for managing bacterial diseases?

<p>Practicing crop rotation with cereals (C)</p> Signup and view all the answers

Which method is recommended to manage bacterial blight of cotton according to the text?

<p>Delinting cotton seed with concentrated sulphuric acid (B)</p> Signup and view all the answers

What is an effective measure to avoid bacterial disease entry mentioned in the text?

<p>Exclusion of disease entry from diseased to healthy tracts (B)</p> Signup and view all the answers

How can plant sanitation help prevent bacterial diseases, as per the text?

<p>Protecting injured plant parts during cultural operations (C)</p> Signup and view all the answers

Which practice is suggested for eliminating seed-borne pathogens according to the text?

<p>Soaking rice seeds in 0.025% streptocyclic solution (A)</p> Signup and view all the answers

What agricultural practice may help reduce the incidence of Pseudomonas solanacearum on tobacco plants according to the text?

<p>Immediately growing tobacco after maize (C)</p> Signup and view all the answers

What is the main function of phloem vessels in plants?

<p>To transport sugars from the leaves to other parts of the plant (B)</p> Signup and view all the answers

How do aphids obtain sugars from plants?

<p>Aphids use needle-like mouth parts to puncture the plant stems and tap directly into the sugar-rich phloem. (B)</p> Signup and view all the answers

What is the main way that bacterial plant pathogens can be disseminated?

<p>By wind-blown soil and sand particles that cause plant wounding (B)</p> Signup and view all the answers

What is a common symptom of plant diseases caused by bacteria?

<p>All of the above (D)</p> Signup and view all the answers

How can bacteria gain entry into plants to cause infection?

<p>Both (b) and (c) (A)</p> Signup and view all the answers

What is the main way that Mycoplasma bacteria are introduced into plants?

<p>Mycoplasma bacteria grow inside aphids and other sap-sucking insects and are then introduced into plants. (A)</p> Signup and view all the answers

What is the primary difference between a sign and a symptom of plant disease?

<p>A sign is physical evidence of the pathogen, while a symptom is a visible effect on the plant caused by the pathogen. (A)</p> Signup and view all the answers

Which of the following is NOT a symptom of bacterial canker on tomato, capsicum, and chilli plants?

<p>Seedlings may die, and older plants may wilt and die eventually. (C)</p> Signup and view all the answers

Which bacterial species is the causative agent of bacterial soft rot in a wide range of vegetable crops?

<p>Pseudomonas spp., Erwinia spp. (D)</p> Signup and view all the answers

What are the typical symptoms of bacterial leaf spot/bacterial spot on cucurbits?

<p>Begin as small water-soaked/greasy spots on underside of leaves with corresponding yellowing on upper side; fruit may produce light-brown ooze from water-soaked markings. (B)</p> Signup and view all the answers

Which of the following is NOT a symptom of bacterial blight on peas?

<p>Wilting and rapid death of plants without any spotting or yellowing. (C)</p> Signup and view all the answers

What are the symptoms of bacterial brown spot on beans?

<p>Small dark spots on leaves. (C)</p> Signup and view all the answers

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