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Oral: Contributions of Plant Viruses to Phytobiome Research


Viruses in nature: Persistent plant viruses.
R. VALVERDE (1) (1) Louisiana State University Agricultural Center, U.S.A.

In nature, viruses are ubiquitous and play an important role in ecosystems. It has been shown that they are the most common biological entity of fresh and sea water. Plant viruses can be divided into two categories: acute and persistent. Acute viruses cause symptoms in their plant hosts. Most acute viruses cause diseases in economically important crops, and infected plants can be found everywhere crops are grown. In most cases, the effect of acute viruses on the plant phenotype consists of foliar discolorations and tissue malformations. In contrast, persistent viruses do not cause detectable symptoms and have been reported in specific cultivars of many economically important crop species. Most persistent viruses in plants have been detected by electrophoretic analyses of viral dsRNAs or by detection methods based on nucleotide sequencing. Preliminary studies suggest that persistent viruses do not appear to be common in nature. In a survey for persistent viruses in non-cultivated plant species conducted in Louisiana, only 9 of 132 plant species belonging to 60 families were found to contain persistent viruses. Of those viruses detected, six were in the family Endornaviridae. The role that persistent viruses play in the plant host is not known.