IDENTIFICATION OF POTEXVIRUS ISOLATES FROM CREEPING PHLOX AND TRAILING PORTULACA AS STRAINS OF ALTERNANTHERA MOSAIC VIRUS, AND COMPARISON OF THE 3´-TERMINAL PORTION OF THE VIRAL GENOMES
Potexvirus isolates from creeping phlox (Phlox stolonjfera) and trailing portulaca (Portulaca grandiflora) obtained from commercial nurseries were found to react strongly with polycloiial antiserum against Papaya mosaic virus (PapMV). Cloning and sequencing of a phlox isolate from Pennsylvania revealed that the coat protein (CP) gene was c.97% identical at the amino acid level to the CP gene sequence of Alternanthera mosaic virus (Geering and Thomas, 1999), and only c.75% to the CF of PapMV.
... full genomic sequence of the phlox isolate was then determined. The regions to the 5' of the CF gene were found to be more closely related to (but distinct from) PapMV than to any other characterized potcxvirus. This phlox potexvirus isolate was therefore named AItM V-PA. The host range of AItM V-PA was found to he similar to that of the Australian isolate, AltM V-Au. The 3'-terminal portion of the genome of the portulaca potexvirus isolate, and of additional potexvirus isolates from two phlox cultivars from commercial nurseries in Maryland, were also cloned and sequenced. The sequences of these isolates were similar to those of AItMV-Au and AItMV-PA, and the isolates were designated AItMV-Po (Portulaca), AItMV-SP (creeping phlox 'Sherwood Purple'), and AItMV-BR (creeping phlox 'Blue Ridge'). Each of the phlox and portulaca isolates reacted strongly with antiserum to A1tM V-Au, and also with anti-Pap\IV antiserum. The host range of A1tMV includes several ornamentals; these findings suggest that AItMV may be quite widespread, and may be mis-diagnosed as PapMV.