Satellites of Plant Viruses

SUMMARYThe stock culture of solanum nodiflorum mottle virus (SNMV) was freed from RNA-2 by passage through single lesions induced in inoculated leaves of Nicotiana debneyi by dilute inocula of partially purified SNMV RNA-1. This isolate (S1) was indistinguishable serologically and in symptomatology from the stock culture of SNMV. Using a sensitive bioassay for detecting RNA-2, no SNMV RNA-2 was found in RNA from particles of the S1 isolate purified after three successive passages in Nicotiana clevelandii. Addition of SNMV RNA-2 (which is not infective alone) had little or no effect on the infectivity of S1 RNA but restored the RNA content of particles to that found in the stock culture (RNA-1 and RNA-2). However, S1 did not support the replication of the RNA-2 from lucerne transient streak virus (LTSV). The possible interaction of the RNA-2 species from LTSV and SNMV with the genomes of other plant viruses was tested by mixing the RNA-2 species with nucleic acid from 11 other viruses. The survival of RNA-2 activity on inoculated leaves for up to 15 days complicated the interpretation of the results of these tests but a small amount of LTSV RNA-2 and SNMV RNA-2 was obtained only from particles of turnip rosette virus purified from plants inoculated with the relevant RNA mixtures. These and other data suggest that these RNA-2 molecules with physicochemical properties similar to viroids found in particles of some sobemoviruses are satellite RNA species whose multiplication is assisted by some, but not all, of the viruses in this group.

Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 97%

See 1 more Smart Citation

Satellite Nature of the Viroid-like RNA-2 of Solanum Nodiflorum Mottle Virus and the Ability of Other Plant Viruses to Support the Replication of Viroid-like RNA Molecules

Jones¹,

Mayo²

1984

“…This sequence difference is reflected in the different products obtained by translation in vitro of the satellite RNA species (Fritsch et al, 1984). Moreover, there are functional differences between the two satellites, for each satellite is dependent on RNA-1, which must come from a TBRV strain of the same serotype as that with which the satellite naturally occurs, and not from a strain of the other serotype (Murant & Mayo, 1982).…”

Section: Tbr V Nucleotide Sequence Homologiesmentioning

confidence: 99%

Nucleotide Sequence Homologies among RNA Species of Strains of Tomato Black Ring Virus and Other Nepoviruses

Dodd¹,

Robinson²

1984

SUMMARYNucleotide sequences of the genome RNA species of four strains of tomato black ring virus (TBRV), two each from the Scottish and German serotypes, were compared by hybridization with complementary DNA copies. Within each serotype 90 ~ or more homology was observed between the corresponding RNA species of each pair of strains. Between serotypes greater differences were found, with 30 to 40~ of RNA-1 sequences and only about 10~ of RNA-2 sequences being common to all four strains. Hybridization reactions between RNA species and complementary DNA preparations representing different serotypes proceeded more slowly, and the hybrids melted at lower temperatures than those between homologous combinations, indicating that the apparently conserved sequences are similar, but not identical, in the two serotypes. Satellite RNA species from two TBRV strains in different serotypes had only about a quarter of their sequences in common. Limited nucleotide sequence homology was found between the genome RNA species of TBRV and those of the serologically distantly related grapevine chrome mosaic, cacao necrosis and artichoke Italian latent viruses, but not between TBRV RNA species and those of seven serologically unrelated nepoviruses.

“…Most satellites reported thus far are RNA molecules about 300 to 1400 nucleotides in length and have been found in association with plant viruses belonging to a number of different groups (for review, see Murant & Mayo, 1982). As far as is known, viral satellites lack extensive nucleotide sequence homology with the genomic RNAs of their helper viruses.…”

mentioning

confidence: 99%

Cucumovirus Satellite RNAs Cannot Replicate Autonomously in Cowpea Protoplasts

Linthorst¹,

Kaper

1985

SUMMARYPurified preparations of peanut stunt virus-associated RNA 5 (PARNA 5) and cucumber mosaic virus-associated RNA 5 (CARNA 5) were used to inoculate cowpea protoplasts, alone or together with their respective helper viruses. After incubation of the protoplasts for up to 5 days, total nucleic acid was extracted, denatured, electrophoresed, transferred to nitrocellulose membranes and hybridized to cDNA probes specific for satellite and viral RNA. Satellite replication could be detected only in protoplasts infected with mixtures of satellite and viral RNA, not in those inoculated with satellite RNA alone. These results suggest that the dependence of cucumovirus satellite RNAs on their helpers is on the replication function rather than on the spreading and/or encapsidation functions of the helper virus.