A novel double-stranded RNA virus detected in Primula malacoides is a plant-isolated partitivirus closely related to partitivirus infecting fungal species

Abstract

A novel virus was detected in ornamental plants of Primula malacoides Franch exhibiting typical yellow-edge symptoms. Two double-stranded RNA (dsRNA) segments, of 2390 bp and 2344 bp, respectively, were extracted from plant tissues, and these same dsRNAs were detected from purified virions of about 35 nm in diameter. The two dsRNAs, putatively encoding partitivirus-related RNA-dependent RNA polymerase and capsid protein, were sequenced. Analysis of phylogenetic relationships and genomic structures indicated that these two dsRNAs together make up the genome of a novel partitivirus. This virus was found to be more closely related to the fungus-infecting partitiviruses than to the ones that infect plants and was designated as Primula malacoides virus 1 (PmV1). It is strongly suggested that this novel virus be classified as a member of the genus Partitivirus.