Discovery of Mycoviruses:

M. Hollings of Glasshouse Crop Research Institute, USA for the first period gave experimental evidence of viruses in cultivated mushroom Agaricus bisporus causing die-gain sickness in 1962. The most characteristic and consistent features of mushroom virus diseases are the loss of crop and the degenerat in marginal note to of mycelium in the compost.

Before it, no experimental evidence in this area presence of viruses in fungi was at hand even if viruses were thought to be the cause of certain abnormalities in fungi. Several terms have been proposed to denote such viruses, viz., fungal viruses, mycophages, dsRNA plasmids, mycoviruses and virus-gone particles (VLPs); the last two terms have been frequently used by the microbiologists.

Since their discovery, mycoviruses have been reported from all major taxonomic groups of fungi, the number of fungal genera ranging from nearly 50 to 60. Some-important fungi containing mycoviruses are Agaricus bisporus (25-50 nm), Alternaria tenuis (30-40 nm), Aspergillus foetidus (40-42 nm), A. glaucus (25 nm), A. niger (40-42 nm).

Penicillium brevicompactum (40 nm) P. chrysogenum (35 nm), P. funiculosum (25- 30 nm) P. notatum (25 nm), P. stoioniferum (40-45 nm), Peziza ostrachoderma (17 x 350 nm), Endothiaparasitica (300 nm), Laccaria laccata (28 nm), Stemphilium botryosum (25 nm; VLPs), Saccharomyces cerevisiae (40 nm) etc.

Within brackets bearing in mind-door-door to the declare of each fungal species is unmodified the size of the virion. However, it is attractive to note that most of the species of Penicillium and Aspergillus have been found to be attacked by mycoviruses though the latter arc not found therefore frequently in supplement fungal genera. So far afield completely few mycoviruses have been adequately characterized, and most are deserted the virus to the fore particles (VPLs) in electron micrographs.