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Updated: Dec 22, 2025

Combining Analysis of DNA in a Crude Virion Extraction with the Analysis of RNA from Infected Leaves to Discover New Virus Genomes
Published on: July 27, 2018
Complete genome sequence of a novel toti-like virus from the plant-pathogenic oomycete Phytophthora cactorum
1Natural Resources Institute Finland (Luke), Natural Resources Unit, Forest Health and Biodiversity, Latokartanonkaari 9, 00790, Helsinki, Finland. anna.poimala@luke.fi.
Abstract:
This report describes the complete genome sequence of a double-stranded RNA (dsRNA) virus infecting the oomycetous plant pathogen Phytophthora cactorum. The virus genome consists of a single dsRNA segment of 5699 bp with two open reading frames predicted to overlap with each other and encoding a putative capsid protein of 705 aa and an RNA-dependent RNA polymerase of 779 aa. Sequence comparisons indicated that this virus, designated as "Phytophthora cactorum RNA virus 1" (PcRV1), shares the highest sequence similarity with the unclassified Pythium splendens RNA virus 1 (58% RdRp aa sequence identity). Phylogenetic analysis revealed that these two oomycete viruses group together with Giardia lamblia virus (GVL; family Totiviridae) and several unclassified toti-like viruses from arthropods, fish and fungi. This is the first report of a toti-like virus in a member of the genus Phytophthora and the first virus characterized in P. cactorum.
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