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.
Biologisches Institut, Abteilung für Molekularbiologie und Virologie der Pflanzen, Universität Stuttgart, Pfaffenwaldring 57, Stuttgart 70550, Germany.
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Unseld
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Ringel
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Konrad
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Lauster
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Frischmuth
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