Abstract:

Double stranded RNA (dsRNA) were extracted from leaf tissues of radish (Raphanus sativus-root cv. Yidianhong) grown in Hangzhou China. Complementary DNAs corresponding to the dsRNA segments were obtained by using a modified single primer amplification technique (SPAT), and followed by cloning and sequencing. The results revealed that a new dsRNA sequence, different from all the previously reported sequences RasR1-RasR5, was obtained. And the newly detected RasR 6 (EU285027) was found to be 1778 bp in length. It predicted that the positive strand of RasR 6 potentially encoded a protein of about 55.1 kDa, containing 502 amino acids. Five members of Partitiviridae, all of which encoded putative viral CPs, were found to have some identity with RasR 6. Multiple alignments showed that RasR 6 were highly conserved at the 5(UTR regions with RasR 1 and RasR 2 previously reported from the same radish varities, but had no similarity with RasR 3-RasR 5. Thus, it could be presumed that both RasR 6, RasR 1 and RasR 2 should belong to Raphanus sativus virus 1(RasV 1), and RasR 6 encods CP together with RasR 2, or is a satellite dsRNA of this virus.

Key words: Raphanus, double-stranded RNA, Partitiviridae, Raphanus sativus virus 1