RESUMO
Viruses are most frequently discovered because they cause disease in organisms of importance to humans. To expand knowledge of plant-associated viruses beyond these narrow constraints, non-cultivated plants of the Tallgrass Prairie Preserve, Osage County, Oklahoma, USA were systematically surveyed for evidence of the presence of viruses. This report discusses viruses of the family Tombusviridae putatively identified by the survey. Evidence of two carmoviruses, a tombusvirus, a panicovirus and an unclassifiable tombusvirid was found. The complete genome sequence was obtained for putative TGP carmovirus 1 from the legume Lespedeza procumbens, and the virus was detected in several other plant species including the fern Pellaea atropurpurea. Phylogenetic analysis of the sequence and partial sequence of a related virus supported strongly the placement of these viruses in the genus Carmovirus. Polymorphisms in the sequences suggested existence of two populations of TGP carmovirus 1 in the study area and year-to-year variations in infection by TGP carmovirus 3.