Complete nucleotide sequence and genome organization of a Chinese isolate of tobacco bushy top virus *

Abstract

The complete nucleotide sequence of a Chinese isolate of tobacco bushy top virus (TBTV), designated TBTV-Ch, was determined from cDNA generated from double-stranded RNA extracted from diseased tobacco. The genome is 4152 nucleotides (nt) in size, contains four putative open reading frames (ORFs) and untranslated regions of 10 nt and 645 nt at the 5' and 3' ends, respectively. In genome organization and in the amino acid sequence of its potential products, the RNA of TBTV-Ch is similar to other umbraviruses sequenced to date. The results suggested that TBTV should be regarded as a definitive species of the genus Umbravirus.

Complete nucleotide sequence and genome organization of a Chinese isolate of Tobacco vein distorting virus

“…Using primers based on the partial sequence previously determined [12] several attempts were made to obtain the 5 0 and 3 0 regions of TVDV using the T4 RNA ligase mediated RACE method [18]. These were only partially successful and after the successful purification of virions, viral RNAs were extracted from these using Trizol LS Reagent (Invitrogen) and were used as templates for determination of full-length genome sequence.…”

“…A DNA fragment containing the entire coat protein (CP) sequence was amplified by reverse transcription-polymerase chain reaction (RT-PCR) using primers based on the partial sequence of TVDV [12]. The RT-PCR product was cloned, sequenced and sub-cloned into a prokaryotic expression vector pSBET [15].…”

“…The complete sequence and genome organization of a Chinese isolate of TBTV (from Baoshan City, Yunnan Province) indicated that it is a definitive species of the genus Umbravirus [5]. Umbraviruses do not form their own virions [6][7][8] but are encapsidated by the coat protein of a helper virus that is also necessary for transmission by aphids [9,10].…”

“…A partial sequence of TVDV obtained earlier suggested that it was a virus in the family Luteoviridae but the insufficient information is provided to classify it in a more precise manner [11,12]. Viruses in this family have isometric virions from 25 to 30 nm in diameter and contain a monopartite linear, positive-sensed single-stranded RNA.…”

Structural alteration of a BYDV-like translation element (BTE) that attenuates p35 expression in three mild Tobacco bushy top virus isolates

“…Although aphid transmission of TBTV requires the presence of TVDV and its coat protein (CP), TBTV is independently pathogenic 21 . TBTV has a positive single-strand RNA genome of 4152 nt lacking a 5′ cap structure and a 3′ poly (A) tail 22 . TBTV encodes four ORFs that encode the replicase components including p35 and its −1 frameshift product p98 (the RdRp) 23, 24 and the movement proteins p26 and p27 25, 26 .…”