Taxonomy of Potyviruses: Current Problems and Some Solutions

Abstract

There are two major requirements for potyvirus taxonomy; group-specific criteria and criteria which discriminate between distinct viruses and strains. This review discusses the relative merits in potyvirus taxonomy of molecular parameters, such as gene sequence data, nucleic acid hybridization, coat protein sequence data, or high-performance liquid chromatography peptide profiles, and phenotypic characteristics, such as particle morphology, host range, symptomatology, cross-protection, cytoplasmic inclusion morphology, and serology. Coat protein and gene sequence data are the most useful criteria, as they can be used to distinguish viruses from strains and to establish evolutionary relationships between groups of distinct potyviruses. This has led to the revised classification of some viruses and strains and to the clarification of previously conflicting and inconsistent biological properties. It has also provided a sound basis for subgrouping potyviruses. An analysis of the data supports the view that the potyvirus group, including the non-aphid-transmitted viruses, should be elevated to family status, that the vector transmission mode, which correlates with major sequence diversity, should define the four genera, and that distinct potyviruses correspond to species and their variants to strains.

Resistance in plants transformed with the P1 or P3 gene of tobacco vein mottling potyvirus.

“…Potyviruses, the largest and most destructive group of plant viruses (Ward & Shukla, 1991), have a single-strand plus-sense RNA genome of about 10 kb with a single open reading frame (ORF). The translation product of this ORF is processed by three virus-encoded proteinases to yield a CP and at least seven non-structural proteins (Riechmann et al, 1992 ;Dougherty & Semler, 1993).…”

Biological and Molecular Detection of a virus infecting Wedelia trilobata (Linn.) Hitchc (A Medicinal Herb)

“…Based on preliminary investigations it was confirmed that the virus belongs to Potyvirus group of family Potyviridae. The potyvirus group (named for its prototypical member, potato virus Y (PVY)) is the largest of the 34 plant virus groups and families currently recognised [12]. This group contains at least 180 definitive and possible members (30% of all known plant viruses) which cause significant losses in agricultural, pastural, horticultural and ornamental crops [12].…”

“…The potyvirus group (named for its prototypical member, potato virus Y (PVY)) is the largest of the 34 plant virus groups and families currently recognised [12]. This group contains at least 180 definitive and possible members (30% of all known plant viruses) which cause significant losses in agricultural, pastural, horticultural and ornamental crops [12]. This is for the first time that potyvirus infecting Wedelia trilobata have been reported from Aligarh India.…”

Complete nucleotide sequences of two soybean mosaic virus strains differentiated by response of soybean containing the Rsv resistance gene

“…Changes at positions 2809 and 3065 occur within the N-and C-terminal regions of the CP, which are known to be highly variable among potyviruses. But the change from methionine in strain G2 to isoleucine in G7 at amino acid position 3018 occurs within the trypsinresistant core, which displays significant amino acid identity among all potyviruses examined (Ward & Shukla, 1991). A recent report has shown that a change from glycine to proline in the virus CP correlates with ability of a strain of potato virus X to overcome resistance (Kohm et al, 1991).…”