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In this article we will discuss about the history of plant virology.
In 1879, Adolf Mayer (Director of the Agricultural Experiment Station at Wageningen, The Netherlands) was the first to study this disease of tobacco. He is credited as the first person to transmit tobacco mosaic virus by using the extracts from the diseased plant as the inoculum to the other healthy plants. In 1886, he published a paper in which he described in detail the disease and its symptoms.
1892, Dmitri Ivanowski did a number of filtration experiments by using porcelain Chamberland filter. This filter was considered to be the ultimate test for bacteria, as they would be retained on the filter. He determined that the cause of tobacco mosaic was either an un-culturable bacterium (smaller than any other known bacterium) or the result of a toxin produced by the bacteria.
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1898, Martinus Beijerinck repeated the filtration experiments and did not find any microbe associated with the disease. He concluded that the filtrate was infectious that passed through porcelain filters. He opined that it was a contagium vivum fluidum (i.e. a contagious living fluid).
He conducted other experiments and found the agent causing the disease was indeed soluble, the agent reproduced in the diseased plant, the infectious extract was stable during a 3 months test, virulence did not increase or decrease in the extract, the agent remained viable even when tissue was dried, and that heating the extract to 90°C inactivated it. He put further existence that it was not bacterial disease. He correctly deduced that it moved through the phloem.
In 1935, W.M. Stanley (an American scientist) added ammonium sulfate to tobacco juice extracted form infected tobacco leaves and obtained a crystalline protein sediment, which could be rubbed on tobacco to cause disease.
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He concluded that the virus was an autocatalytic protein that could multiply within the living cells. Later on it was proved to be wrong. In 1946, he received the Nobel Prize in Chemistry for this work.
In 1936, F.C. Bawden and colleagues demonstrated that the crystalline preparations of virus actually consisted of not only protein but also a small amount of ribonucleic acid (RNA). In 1939, Von G. A. Kausche and colleagues viewed particles of tobacco mosaic virus with an electron microscope. Later on through, crystallography, ELISA test and the other modern techniques much information’s were gathered.
