Virus-specific adaptations for the production of a pseudorecombinant virus formed by two distinct bipartite geminiviruses from Central America.
Most whitefly-transmitted geminiviruses possess bipartite genomes comprising DNAs A and B. The production of viable pseudorecombinants by reassortment of infectious cloned components is generally limited to isolates/strains of a particular virus. Following exchange of cloned genomic components of Sida golden mosaic virus from Costa Rica (SiGMV/Co) and Sida golden mosaic virus from Honduras (SiGMV/Ho(yv)), the pseudorecombinant viruses were infectious in various plant species. Three DNA B components (B(1), B(2), B(3)), different in a few nucleotides, were isolated from Sida rhombifolia naturally infected with SiGMV/Ho(yv). Only SiGMV/Ho(yv) DNA B(2) was able to form a viable pseudorecombinant with SiGMV/Co DNA A. In protoplasts, as well as in inoculated leaves, SiGMV/Co DNA A trans-replicated the heterogenomic SiGMV/Ho(yv) DNA B(1) component, indicating that impaired movement is involved in the deficiency of SiGMV/Ho(yv) DNA B(1) to form a pseudorecombinant virus with SiGMV/Co DNA A. Even after extensive mutation analysis of SiGMV/Ho(yv) DNA B(1) and B(2), we were unable to pinpoint differences in SiGMV/Ho(yv) DNA B(2) that allowed the formation of a pseudorecombinant virus with SiGMV/Co DNA A. We observed a gradual increase of infectivity from noninfectious SiGMV/Co DNA A/SiGMV/Ho(yv) DNA B(1) and B(3) pseudorecombinant virus to pseudorecombinant viruses showing normal systemic spread of both genomic components associated with symptomatic plants.
Unseld
S
S
Biologisches Institut, Abteilung für Molekularbiologie und Virologie der Pflanzen, Universität Stuttgart, Pfaffenwaldring 57, Stuttgart 70550, Germany.
Ringel
M
M
Konrad
A
A
Lauster
S
S
Frischmuth
T
T
D000222:Adaptation, Physiological; D001483:Base Sequence; D002489:Central America; D003364:Costa Rica; D004261:DNA Replication; D004279:DNA, Viral; D017791:Geminiviridae / Q000235:genetics* / Q000502:physiology; D006721:Honduras; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010947:Plants, Toxic; D016865:Reassortant Viruses / Q000235:genetics*; D014026:Nicotiana / Q000821:virology; D014779:Virus Replication
D004279:DNA, Viral