Detection, isolation, and characterization of high molecular weight double-stranded RNAs in plants infected with velvet tobacco mottle virus.
Two species of double-stranded (ds) RNA were detected in Nicotiana clevelandii infected with velvet tobacco mottle virus (VTMoV) which were not present in healthy plants. The ds-RNAs were first detected by polyacrylamide gel electrophoresis 2 to 4 and about 8 days after inoculation in the inoculated and systemically infected leaves respectively. Thereafter the concentrations of ds-RNA increased significantly. The VTMoV-specific ds-RNA was purified from plants 10 to 14 days after inoculation. The ds-RNA was electrophoresed on agarose gels, transferred to nitrocellulose paper and blot hybridized with 32P-labelled probes specific to nucleotide sequences of either the positive or negative sense strands of the various VTMoV RNA components: the linear single-stranded (ss) RNA 1 of Mr about 1.5 x 10(6) or RNAs 2 and 3, the circular and linear forms respectively, of viroid-like ss-RNA with Mr of about 1.2 x 10(5). One of the ds-RNA species, with Mr of about 2.8 x 10(6), was shown to contain base sequences specific to RNA 1 and the other, with Mr of about 3.6 x 10(6), specific to RNAs 2 and 3. The possible significance of the VTMoV-specific ds-RNAs to replication of the virus is discussed.
Chu
P W
PW
Department of Plant Pathology, Waite Agricultural Research Institute, University of Adelaide, South Australia.
Francki
R I
RI
Randles
J W
JW