Eight plant species that were believed to be resistant to mechanical inoculation with potato spindle tuber viroid (PSTV) were inoculated with virulent Agrobacterium tumefaciens strains the recombinant Ti plasmids of which contained infectious dsDNA copies of PSTV. PSTV-related RNAs (including its circular and linear forms) were detected in galls and roots of the six species which developed crown galls; those which did not (Zea mays and Phaseolus vulgaris) did not contain detectable levels of PSTV-related RNA. None of the eight species contained detectable PSTV-related RNA in their foliage. Although PSTV appears to be stable and to be translocated in non-hosts, analysis of RNase-resistant dsRNA preparations from Agrobacterium-inoculated sunflower suggests that PSTV does not undergo normal RNA-directed replication. Agrobacterium-mediated inoculation of Solanum acaule accession OCH11603 was followed by the appearance of PSTV in the foliage, suggesting that the previously reported resistance of this plant to PSTV infection is actually resistance to mechanical inoculation rather than immunity to infection.
BARKERJ. M., MCINNESJ. L., MURPHYP. J., SYMONSR. H.1985; Dot-blot procedure with [32P]DNA probes for the sensitive detection of avocado sunblotch and other viroids in plants. Journal of Virological Methods 10:87–98
BEIERH., SILERD. J., RUSSELLM. L., BRUENINGG.1977; Survey of susceptibility to cowpea mosaic virus among protoplasts and intact plants from Vigna sinensis. Phytopathology 67:917–921
DHAESEP., DE GRèVEH., DECRAEMERH., SCHELLJ., VAN MONTAGUM.1979; Rapid mapping of transposon insertion and deletion mutations in the large Ti-plasmids of Agrobacterium tumefaciens. Nucleic Acids Research 7:1837–1849
FULTONR. W.1964 Transmission of plant viruses by grafting, dodder, seed and mechanical inoculation. Plant Virology39–67 Edited by CorbettM. K., SislerH. D. Gainesville: University of Florida Press;
GARDNERR. C, CHONOLESK. R., OWENSR. A.1986; Potato spindle tuber viroid infections mediated by the Ti plasmid of Agrobacterium tumefaciens. Plant Molecular Biology 6:221–228
HAMMONDR. W., OWENSR. A.1987; Mutational analysis of potato spindle tuber viroid reveals complex relationships between structure and infectivity. Proceedings of the National Academy of Sciences, U.S.A 84:3967–3971
HIEBERTE., BANCROFTJ. B., BRACKERC. E.1968; The assembly in vitro of some small spherical viruses, hybrid viruses and other nucleoproteins. Virology 34:492–508
HUBERR., REZELMANG., HIBIT., VAN KAMMENA.1977; Cowpea mosaic virus infection of protoplasts from Samsun tobacco leaves. Journal of General Virology 34:315–323
HUTCHINSC. J., KEESEP., VISVADERJ. E., RATHJENP. D., MCINNESJ. E., SYMONSR. H.1985; Comparison of multimeric plus and minus forms of viroids and virusoids. Plant Molecular Biology 4:293–304
KEESEP., SYMONSR. H.1985; Domains in viroids: evidence of intermolecular RNA rearrangements and their contribution to viroid evolution. Proceedings of the National Academy of Sciences, U.S.A 82:4582–4586
MCMASTERG. K., CARMICHAELG. G.1977; Analysis of single- and double-stranded nucleic acids on Polyacrylamide and agarose gels by using glyoxal and acridine orange. Proceedings of the National Academy of Sciences, U.S.A 74:4835–4838
MELTOND. A., KRIEGP. A., REBAGLIATIM. R., MANIATIST., ZINNK., GREENM. R.1984; Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter. Nucleic Acids Research 12:7035–7056
ODELLJ. T., NAGYF., CHU AN-H.1985; Identification of DNA sequences required for activity of the cauliflower mosaic virus 35S promoter. Nature, London 313:810–812
OWENSR. A., DIENERT. O.1982; RNA intermediates in potato spindle tuber viroid replication. Proceedings of the National Academy of Sciences, U.S.A 79:113–117
SäNGERH. L., RAMMK.1975 Radioactive labelling of viroids. Modification of the Information Content of Plant Cells229–252 Edited by MarkhamR., DaviesD. R., HopwoodD. A., HorneR. W. Amsterdam: Elsevier;
SHEWMAKERC. K., CATONJ. R., HOUCKC. M., GARDNERR. C.1985; Transcription of cauliflower mosaic virus integrated into plant genomes. Virology 140:281–288
TABLERM., SäNGERH. L.1985; Infectivity studies on different potato spindle tuber viroid (PSTV) RNAs synthesized in vitro with the SP6 transcription system. EMBO Journal 4:2191–2199