Potyvirus serology, sequences and biology

Abstract

Summary. Amino acid sequences of the cytoplasmic cylindrical inclusion protein (CIP), large nuclear inclusion protein (NIb), and coat protein (CP) of potyviruses were re-examined in light of reported serological relationships, and correlated with known and deduced biological functions. No obvious correlations were observed between either amino acid sequences or epitopes recognized by monoclonal antibodies and the natural host ranges of the potyviruses examined. Whereas the identified sequence motifs of the RNA helicase (CIP) and replicase (NIb) are predicted to be antigenic, most of the conserved sequences and epitopes in the CIP, NIb and CP were presumed to be maintained for structural rather than functional reasons. Three possible potyvirus clusters are proposed on the basis of the length and composition of the virion surface-exposed amino terminal extension of the CP; these clusters do not correlate with overall CP sequence homology, host range, or vectors, but are of potential evolutionary significance and hence of possible taxonomic value.

Cylindrical inclusion protein of potato virus A is associated with a subpopulation of particles isolated from infected plants

“…Potato virus A (PVA) belongs to the genus Potyvirus in the family Potyviridae. A distinct feature of this virus family is the ability to induce formation of laminate or pinwheelshaped cytoplasmic inclusion bodies, which consist of accumulated cylindrical inclusion protein (CI; reviewed by Edwardson, 1992;Hammond, 1992). The first indication of possible involvement of CI in virus movement came when CIs of several potyviruses were shown to form cone-shaped structures anchored to the cell wall or plasma membrane in close proximity to plasmodesmata (Lawson & Hearon, 1971;Langenberg, 1986;Rodríguez-Cerezo et al, 1997;Roberts et al, 1998).…”

Le point sur l'utilisation de sérums anti‐protéines non structurales pour l'étude de la sharka1

“…Des analyses de sequences de differents potyvirus ou de plusieurs souches d'un m&me virus ont montre que les regions du genome apparaissant les plus conservees sont, apres le gene de la proteine 'b' des NI, les genes de l'helicase (CI) et de la protease (NIa) (Ward et al, 1992). Cependant, les homologies de sequence relevees ne concernent pas systematiquement les regions prevues (programme ANTIGEN) comme etant les plus antigeniques (Hammond, 1992). Au cows d'etudes immunologiques, de nombreux anticorps polyclonaux diriges contre les proteines non structurales presentent des reactions croisees avec d'autres potyvirus.…”