Viruses plant pathogenic

The tobacco mosaic virus (center right), a plant pathogen, has a structure similar to that of MB, but contains ssRNA instead of DNA. The poliovirus, which causes poliomyelitis, is also an RNA virus. In the influenza virus, the pathogen that causes viral flu, the nucleocapsid is additionally surrounded by a coat derived from the plasma membrane of the host cell (C). The coat carries viral proteins that are involved in the infection process. 

Public health aspects. A limited number and a relatively small quantity of medical antibiotics have been introduced in agricultural use as shown in Table I. Most agricultural antibiotics have been used only for plant protection purposes and not used in medical treatment. Therefore, the public s concern for the environmental problem of antibiotics must be different in the two areas where antibiotics are used. Agricultural antibiotics do not involve primarily the health of the individual, but their use has macroenvironmental consequences. Most human infectious diseases are caused by bacteria and viruses, while plant pathogens... 

A more scientific term for disease-causing organisms is the word pathogen. In addition to fungi and bacteria, viruses, nematodes, and parasitic plants are plant pathogens. These organisms run the spectrum in food preferences. Some are nourished mostly from dead organic... 

A general term for compounds whose biosynthesis is elicited or induced in plants as the result of attack by a pest is "phytoalexin". These higher plant metabolites are antibiotic to certain potential plant pathogens and also on occasion to insects (Chapter 13 of this volume). The phytoalexins typically are biosynthesized in greater concentrations when the plant is subjected to stress. Therefore, the attacking agent (fungi, bacteria, or viruses in most work to date) elicits the initiation or increased synthesis of phytoalexins (antibiotic compounds). 

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