Plant virus

Plant viruses are pathogens of higher plants, such as the animal ( animale ) viruses and bacteriophages are also capable only after penetration into a cell to multiply. Diseases caused by plant viruses have been described in the 16th century, but the discovery of a portability and a specific pathogen was not until the late 19th century by examining the mosaic disease of the tobacco plant. About a quarter of the viruses described around 3600 are plant viruses that belong to or form families together with the animal viruses according to morphology particular virus families. The peculiarity of the plant cell wall, the defense mechanisms and transport systems of a plant also require specific adaptations of plant viruses to their hosts.

In agronomy plant viruses are of great importance due to the economic damage caused by them. This concerns not only the cultivation of ornamental plants, but also important crops such as the potato, tomato or carrot. Transmission of plant viruses to chordates (such as humans) can not be observed due to the special adaptation of the plant virus. In addition to plant viruses, there are also other subcellular pathogens causing similar diseases, but are assigned to viroids or virusoids. The study of plant viruses as well as the plant-pathogenic viroid is known as " Plant Virology " a discipline of virology.

History

The first description of a possible Pflanzenvirose a poem of Japanese Empress Koken from the year 752 is considered. In the poetry collection Man'yōshū the Empress describes the autumnal image yellow grass in the middle of summer. This refers to a yellowing of the leaves of the agrimony ( Eupatorium lindleyanum ) due to an infection with a geminivirus.

As 1551, the first tulips from Constantinople Opel introduced in the Netherlands, attracted the changing color patterns of flowers, the so-called variegation, high sensation. We also observed that these color patterns were transferred to previously monochrome plants, although the breeding multicolored flowers they reached until then only by consuming intersection. Some of the most spectacularly colored varieties of tulips withered and died rapidly, whereas others could be the pattern retained and propagated. In particular, this - although based on a disease process - exceptional property of tulips led to an upsurge of the tulip export from the Netherlands in the 17th century who sought to protect their monopolistic position by prohibiting the export of tulip bulbs and a barely comprehensible price. The Dutch painting in this century remarkably often those affected by plant viruses tulips as theme of still life.

The exploration of these pathological changes of plant dyes and her death began with the evidence of transferability. The agricultural chemist Adolf Mayer investigated the cause of economically important mosaic disease of the tobacco plant, and had in 1886 an infectious cause of the phenomenon after by he could transfer sap from a diseased plant by scoring on a healthy. By dilutions Mayer also demonstrated that it could not be a poisoning. The nature of the pathogen, however, remained unclear. Only when Dimitri Ivanovski 1892 sap ultrafiltered before, it became clear that the cause had to be a bacterium, but a whole new kind of pathogens due to its filterable size. These experiments are considered beginnings of modern virology. Martinus Beijerinck in 1898 could not confirm the hitherto known to him Iwanowskis experiments.

Economic Aspects

In many crop plant viruses cause great economic damage. Often there is a reduction of the biomass produced due to a reduced supply of the plant and reduced Uses parts ( tubers, fruits, leaves ), but also to the death of large plantations. Also, the visual impact of fruit and leaves by a virosis reduces their marketability, even if the mass and quality of fruit should not be affected.

Unlike other pests, such as by fungi, bacteria or parasites, there are no ways to rid an infested plant viruses plant of the infection. In severe infestation acreage usually remains only the burning of the affected plants. Therefore, the containment of Pflanzenvirosen focused on preventive measures. This extends considerably to the interruption of the chain of infection by controlling the carrying insects, use of virus -free seed material, vegetative propagation by cuttings healthy and regular inspection of the plots. Use of green genetic engineering virus-resistant crops were grown. In Hawaii, the papaya industry is protected by a virus- resistant variety against attack by the papaya ringspot virus.

Swell

Current literature

  • Gerhart Drews, Günter Adam, Cornelia Heinze: Molecular Plant Virology, Berlin 2004, ISBN 3-540-00661-3
  • Sondra Lazarowitz D.: Plant Viruses. In: David M. Knipe, Peter M. Howley ( ed. -in- chief): Fields' Virology. 5th edition, 2 volumes Philadelphia 2007, pp. 641-705, ISBN 0-7817-6060-7
  • Sylke Meyer- Kahsnitz: Applied Plant Virology, 1993, ISBN 3-87815-045-8
  • Allan Granoff, Robert G. Webster (eds. ): Encyclopedia of Virology, San Diego (Academic Press), 1999, ISBN 0-12-227030-4

Historical Literature

  • Kenneth M. Smith: Recent advances in the study of plant viruses, Philadelphia 1933
  • John Grainger: Virus diseases of plants, London 1934
  • Kenneth M. Smith: A Textbook of Plant Virus Diseases, Philadelphia 1937, 3rd edition Edinburgh 1972
  • Francis Oliver Holmes: A Handbook of Phytopathogenic Viruses, Minneapolis 1939
  • LO Kunkel: General Pathology of Virus Infections in Plants. In: R. Doerr and C. Hallauer (ed. ): Handbook of Virus Research, Supplement 1, Vienna 1944
  • Kenneth M. Smith: Virus diseases of farm & garden, 1946
  • Wilhelm Troll: The virus problem in ontological point of view ( papers from the entire field of scientific botany with the inclusion of the border areas, Academy of Sciences and Literature in Mainz, ed Frey Wyssling, Seybold, Troll), Wiesbaden 1951
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