#plant_virus__plantviru  a plant pathogen that is a virus consisting of a single strand of RNA
  supertype:  virus__viru  ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic
  subtype:  tobacco_mosaic_virus__TMV  the widely studied plant virus that causes tobacco mosaic; it was the first virus discovered (1892)
  subtype:  viroid__virusoid  a plant virus with its RNA arranged in a circular chromosome without a protein coat
  subtype:  onion_yellow-dwarf_virus  the virus that produces stunting and yellowing of the leaves of onion plants
  subtype:  potato_yellow-dwarf_virus  the virus that produces stunting and yellowing of the leaves of potato plants

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