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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #317254

Research Project: NEW AND EMERGING VIRAL AND BACTERIAL DISEASES OF ORNAMENTAL PLANTS: DETECTION, IDENTIFICATION, AND CHARACTERIZATION

Location: Floral and Nursery Plants Research

Title: Pelarspovirus, a proposed new genus in the family Tombusviridae

Author
item Scheets, Kay - Oklahoma State University
item Jordan, Ramon
item White, Andy - York University
item Hernandez, Carmen - Polytechnic University Of Valencia (UPV)

Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2015
Publication Date: 7/7/2015
Citation: Scheets, K., Jordan, R.L., White, A., Hernandez, C. 2015. Pelarspovirus, a proposed new genus in the family Tombusviridae. Archives of Virology. 160:2385-2393.

Interpretive Summary: A significant factor in the continued growth of the ornamentals industry is the introduction of new plant species and varieties to the trade. However, the introduction of new plant materials also brings the risk of new viral diseases as new crops are introduced or grown in new areas. Viral diseases cause significant losses to production and/or quality, and are impossible to control directly with agrochemicals. Methods to reliably and rapidly detect and identify viruses are necessary for the production of pathogen-free or pathogen-indexed plants, and for general virological investigations. Improved knowledge on genomes and genetic relationships are also essential for epidemiological studies and disease diagnosis and control. Understanding viral genome structures and functions, and the mechanisms of viral pathogenicity, will lead to a better understanding of host-pathogen interactions and mechanisms of plant disease resistance. Over the past several years research on established and new or emerging viruses of geranium has revealed that several of these viruses posses unique biochemical and genomic features that differentiate them from other presumably related viruses. This formal report documents sufficient molecular and phylogenetic support for the creation of the new plant virus genus in the family Tombusviridae. The distinct properties of the proposed six species are described and delineated, the species type member is designated, and the new genus name, Pelarspovirus, is given. Characterization and classification of the viruses infecting ornamental and agronomic plants will add to our knowledge of the taxonomy and biology of these viral plant pathogens and will be applied to the detection and identification of new and emerging viruses infecting ornamentals. Improved detection and differentiation methods for these pathogens will be used by state and federal regulatory officials to make timely and appropriate recommendations in safeguarding the movement of horticultural and agricultural products into and through the United States.

Technical Abstract: Currently, the family Tombusviridae encompasses thirteen viral genera that contain single-stranded, positive-sense RNA genomes and isometric virions; the exception being the genus Umbravirus, whose members do not encode a coat protein (CP). A new genus, tentatively named Pelarspovirus, is proposed to be added to this family and would include five members, with Pelargonium line pattern virus (PLPV) recommended as the type species. Viruses assigned to this proposed genus have monopartite genomes encoding five open reading frames (ORFs) that include two 5´-proximal replication proteins, two centrally located movement proteins (MP1 and MP2) and a 3’-proximal CP that, at least for PLPV, has been shown to act also as suppressor of RNA silencing. Distinguishing characteristics of these viruses include: i) production of a single, tricistronic sub-genomic RNA for expression of MP and CP genes, ii) presence of a non-AUG start codon (CUG or GUG) initiating the MP2 ORF, iii) absence of AUG codons in any frame between the AUG initiation codons of MP1 and CP genes, and iv) sequence-based phylogenetic clustering of all encoded proteins in separate clades from those of other family members.