Assessment of the autonomy of replicative and structural functions encoded by the luteo-phase of pea enation mosaic virus.
The genome of pea enation mosaic virus (PEMV) is composed of two taxonomically unrelated RNAs, interacting to create what has traditionally been considered a bipartite virus. The cohesiveness of this interaction was assessed by examining the autonomy of each RNA in viral replication, coat protein expression and systemic invasion. Using a pea protoplast system, in vitro transcripts of RNA1 were found to be capable of initiating RNA2-independent replication, including the formation of the distinctive nuclear membrane-based replication complex associated with wild-type PEMV infection. Western blotting and electron microscopic analysis demonstrated that the synthesis of the RNA1-encoded coat protein, as well as virion assembly, was also independent of RNA2-directed functions. Mechanical inoculations with transcripts of RNA1 failed to establish a systemic RNA1 infection, whereas inoculations with RNA2 were able to establish a largely asymptomatic systemic infection. Combined inoculum containing RNA1 and RNA2 transcripts were able to recreate wild-type PEMV symptomatology, demonstrating the dependence of RNA1 on RNA2 for mechanical passage. With the notable exception of the adaptation of PEMV to establish a true systemic invasion, these data further strengthen the analogy between PEMV and the helper-dependent complexes associated with members of the luteovirus group.
Demler
S A
SA
Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312.
Borkhsenious
O N
ON
Rucker
D G
DG
de Zoeten
G A
GA
D001483:Base Sequence; D001692:Biological Transport; D002213:Capsid / Q000096:biosynthesis; D007887:Fabaceae / Q000382:microbiology* / Q000648:ultrastructure; D006378:Helper Viruses / Q000235:genetics* / Q000648:ultrastructure; D017793:Luteovirus / Q000235:genetics* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity / Q000648:ultrastructure; D010935:Plant Diseases / Q000209:etiology / Q000382:microbiology; D010946:Plants, Medicinal; D011523:Protoplasts / Q000382:microbiology; D012367:RNA, Viral / Q000235:genetics* / Q000648:ultrastructure; D014774:Virulence / Q000235:genetics; D014779:Virus Replication
D012367:RNA, Viral