Pathogens - Research Article from Macmillan Science Library: Plant Sciences

This encyclopedia article consists of approximately 11 pages of information about Pathogens.
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Types of Pathogens

Bacteria.

The plant pathogenic bacteria are rod-shaped eubacteria. They are prokaryotes, having a chromosome but no nucleus. The cytoplasm has ribosomes but no endoplasmic reticulum and no organelles. The cells have a cell wall and may or may not have flagella.

The first bacterium shown to cause a plant disease, fire blight of pome fruits, was reported by Thomas Burrill in Illinois in 1878. However, it was the research by Erwin F. Smith from 1890 to 1915 that demonstrated the importance of these agents as plant pathogens.

Viruses.

Viruses are nucleoprotein macromolecules. They contain genetic information, either ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), which is covered by protein subunits. Plant pathogenic viruses usually contain RNA rather than DNA. Since viruses are not cellular organisms, they express lifelike characteristics only when within a susceptible host cell. Additionally, since they are not cellular, they do not obtain organic nutrients directly...

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This section contains 3,032 words
(approx. 11 pages at 300 words per page)
Buy the Pathogens Encyclopedia Article
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Macmillan Science Library: Plant Sciences
Pathogens from Macmillan Science Library: Plant Sciences. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.
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