Nucleotide sequence of the genomic RNA of pepper mild mottle virus, a resistance-breaking tobamovirus in pepper.

The entire genomic RNA of a Spanish isolate of pepper mild mottle virus (PMMV-S), a resistance-breaking virus in pepper, was cloned and sequenced and shown to be similar to other tobamoviruses in its genomic organization. It consisted of 6357 nucleotides (nt) and contained four open reading frames (ORFs) which encode a 126K protein and a readthrough 183K protein (nt 70 to 4908), a 28K protein (nt 4909 to 5682) and a 17.5K coat protein (nt 5685 to 6158). This is the first tobamovirus in which none of the ORFs overlap. Both its nucleic acid and predicted protein sequences were compared with the previously determined sequences of other tobamoviruses. The variations and similarities found and their relationship with the pathogenicity of this virus are discussed.

Transformed tomato plants express a satellite RNA of cucumber mosaic virus and produce lethal necrosis upon infection with viral RNA.

Tomato plants transformed with a single copy of a tomato necrosis causing satellite RNA of cucumber mosaic virus (CMV) express the satellite sequence, but the plants show no disease symptoms and have a normal appearance. Upon challenge infection of the F1 progeny with a CMV strain free of any detectable encapsidated satellite the plants accumulated single and double-stranded forms of satellite RNA and developed lethal necrosis.

Nucleotide sequences of 5' and 3' non-coding regions of pepper mild mottle virus strain S RNA.

The nucleotide sequences of the 5' and 3' non-coding regions of pepper mild mottle virus strain S (PMMV-S) RNA were determined; they are more like corresponding sequences of tomato mosaic virus (ToMV) RNA than those of any other tobamovirus reported so far. The 5' leader contains a 68 nucleotide guanosine-free sequence which differs in several nucleotides from the corresponding sequences in genomic RNA of tobacco mosaic virus (TMV) and ToMV. The messenger activity of PMMV-S RNA in vitro and the polypeptide translation products made were similar to those of TMV RNA. It therefore seems unlikely that qualitative or quantitative differences in translation in vivo account for the milder symptoms induced by PMMV-S, and its lesser replication, than TMV. The 3' non-coding region of PMMV-S RNA is 199 nucleotides long and can be folded into the same secondary structure as the RNA of other tobamoviruses.

In vitro translation of cucumoviral satellites. II. CARNA 5 from cucumber mosaic virus strain S and SP6 transcripts of cloned (S)CARNA 5 cDNA produce electrophoretically comigrating protein products.

This report shows that (S)CARNA 5, the satellite of cucumber mosaic virus (CMV) strain S, directs the synthesis of two small proteins in a wheat germ cell-free translation system. The two proteins are produced by the translation of both (S)CARNA 5 purified from CMV virions and the (+) strand purified from double-stranded (S)CARNA 5. In addition, two protein products that comigrate electrophoretically with those above are produced when transcripts synthesized in vitro from full-length (S)CARNA 5 cDNA cloned in the plasmid pSP65 are substituted for (S)CARNA 5 in the translation system. The two proteins therefore must derive from a single (S)CARNA 5 sequence.

In vitro translation of cucumoviral satellites. I. Purification and nucleotide sequence of cucumber mosaic virus-associated RNA 5 from cucumber mosaic virus strain S.

The satellite cucumber mosaic virus (CMV)-associated RNA 5 (CARNA 5) of CMV strain S (CMV-S) which previously had been assigned the capability both to direct the synthesis of two small proteins in vitro (R. A. Owens and J. M. Kaper, 1977, Virology, 80, 196-203) and to induce the tomato necrosis disease in the presence of its helper virus (J. M. Kaper and H. E. Waterworth, 1977, Science, 196, 429-431), has been reinvestigated. Polyacrylamide gel electrophoretic analyses under partially denaturing conditions of CARNA 5 preparations from CMV-S grown in tobacco reveal a mixture of three distinct RNA species which have been isolated and partially characterized. In order of decreasing electrophoretic mobility they have been designated RNA 5, (n)CARNA 5, and (S)CARNA 5, respectively. RNA 5 has been partially sequenced and shown to represent 3'-terminal fragments of the CMV genomic RNAs. (n)CARNA 5 is responsible for the tomato necrosis-inducing properties of the mixture and coelectrophoreses with tomato necrosis-inducing CARNA 5 from CMV strain D. (S)CARNA 5 does not cause tomato necrosis; its complete nucleotide sequence was determined and is compared here to the published sequences of the CARNA 5s of four other CMV strains. A companion paper (M. J. Avila-Rincon et al., 1986, Virology, 152, 455-458) provides unequivocal evidence that the in vitro translation of nonnecrotic (S)CARNA 5 produces two small polypeptides resembling those described earlier.