Plant virus

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Anton Claez: Tulip (watercolor around 1630)

Plant viruses are pathogens in higher plants which, like animal (animal) viruses and bacteriophages, are only able to multiply after penetrating a cell. Plant virus diseases were described as early as the 16th century, but the discovery of a transmissibility and a specific pathogen was only possible at the end of the 19th century by examining the mosaic disease of the tobacco plant. Around a quarter of the 3600 viruses described are plant viruses which, due to their morphological properties, belong to particular virus families or also form families together with animal viruses. The peculiarity of the plant cell wall, the defense mechanisms and transport systems of a plant also require specific adaptations of the plant viruses to their host .

In agricultural science , plant viruses are of great importance because of the economic damage they cause. This not only applies to the cultivation of ornamental plants , but also to important crops such as potatoes , tomatoes and carrots . A transmission of plant viruses to chordates (such as humans) cannot be observed due to the special adaptation of the plant viruses. In addition to the plant viruses, there are also other subcellular pathogens that cause similar diseases, but are assigned to the viroids or virusoids . Research into plant viruses as well as plant pathogenic viroids is called “plant virology” and is a separate discipline of virology.

history

Abraham Bosschaert (1612 - after 1635) Bouquet of flowers with tulips

A poem by the Japanese Empress Kōken from the year 752 is considered to be the first description of a possible plant virus . In the collection of poems Man'yōshū , the empress describes the autumnal image of yellow grass in the middle of summer. What is meant is a yellowish discoloration of the leaves of the water dost ( Eupatorium lindleyanum ) due to an infection with a geminivirus .

When the first tulips from Constantinople were imported into the Netherlands in 1551 , the changing color patterns of the flowers, the so-called variegation , caused a sensation. It was also observed that these color patterns passed to previously single-colored plants, although until then the only way to cultivate multi-colored flowers was through elaborate crossing . Some of the spectacularly colored varieties of tulips dried up and quickly died, while others retained the patterns and could be propagated. In particular, this extraordinary property of tulips - although it is based on a disease process - led to an upswing in tulip exports from the Netherlands in the 17th century, which sought to secure their monopoly position by prohibiting the export of tulip bulbs and a barely comprehensible price. It is striking that Dutch painting in this century uses plant virus-infested tulips as the motif of the still lifes .

Research into these pathological changes in plant coloration and their death began with evidence of transferability. The agricultural chemist Adolf Mayer investigated the cause of the economically important mosaic disease of the tobacco plant and, in 1886, proved an infectious cause of the phenomenon by being able to transfer the sap of a diseased plant to a healthy one by scratching it. By diluting it, Mayer also proved that it could not have been poisoning. However, the nature of the pathogen remained unclear. It was only when Dimitri Iwanowski had previously ultrafiltered the sap in 1892 that it became clear that the cause, due to its filterable size , had to be a completely new type of pathogen rather than a bacterium . These experiments are considered the beginnings of modern virology . In 1898, Martinus Beijerinck was able to confirm Ivanovsky's experiments, which he had not known before.

economic aspects

Plant viruses cause great economic damage in many crops. Often there is a reduction in the biomass generated due to insufficient supply of the plant and reduced useful parts (tubers, fruits, leaves), but also large plantations die. The visual impairment of fruits and leaves by a virus also reduces their marketability, even if the mass and quality of a fruit should not be impaired.

In contrast to other pest infestations such as fungi, bacteria or parasites, there are no ways to rid a plant infected by plant viruses from the infection. In the case of a pronounced infestation of a cultivated area, the only thing left is usually the burned plants. Hence, the containment of plant viruses focuses on preventive measures. This essentially extends to the interruption of the chain of infection by controlling the insects that transmit it, using virus-free seed material, vegetative propagation through healthy cuttings and regular monitoring of the areas under cultivation. Virus-resistant crops were grown with the help of green genetic engineering . In Hawaii , the papaya industry is protected from infestation with the papaya ringspot virus by a virus-resistant variety.

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Current literature

Historical literature

  • Kenneth M. Smith: Recent advances in the study of plant viruses , Philadelphia 1933 [2]
  • John Grainger: Virus diseases of plants , London 1934 [3]
  • Kenneth M. Smith: A Textbook of Plant Virus Diseases , Philadelphia 1937 [4] , 3rd edition Edinburgh 1972
  • Francis Oliver Holmes: Handbook of Phytopathogenic Viruses , Minneapolis 1939 [5]
  • LO Kunkel: General Pathology of Virus Infections in Plants . In: R. Doerr and C. Hallauer (eds.): Handbuch der Virusforschung , 1st supplementary volume, Vienna 1944
  • Kenneth M. Smith: Virus diseases of farm & garden , 1946 [6]
  • Wilhelm Troll: The virus problem from an ontological point of view (treatises from the entire field of scientific botany including the border areas, Academy of Sciences and Literature Mainz, Ed. Frey-Wyssling, Seybold, Troll), Wiesbaden 1951

Individual evidence

  1. ↑ K. Saunders et al .: Aetiology: The earliest recorded plant virus disease . Nature (2003) 422 (6934): p. 831 PMID 12712190 (facsimile of the Japanese Rui-shu-ko-shu edition: [1] )
  2. ^ M. Dash: Tulipomania: The story of the world's most caveted flower and the extraordinary passions it aroused . New York, 1999
  3. ↑ Adolf Mayer: About the mosaic disease of tobacco . The Agricultural Research Stations (1886) 32: pp. 451–467
  4. ↑ Dmitri I. Ivanovskij: O dvuch boleznjach tabaka. Tabacnaja peplitsa. Mozatcnaja bolezn´ tabaka . Sel`skoje chozaistvo i lesovodstvo St. Petersburg (1892) 169: pp. 104–121
  5. ^ MW Beijerinck: About a contagium vivum fluidum as the cause of the blotchy disease of tobacco leaves . Negotiations K. Adad. Wet. Amsterdam (1898) 65: pp. 3-21
  6. ^ OW Barnett and CE Main: Plant Virus Disease - Economic Aspects . In: Allan Granoff, Robert G. Webster (1999) Vol. 2, pp. 1318-1326

See also

Web links

Wiktionary: Plant virus  - explanations of meanings, word origins, synonyms, translations