Trans-Replication of, and Competition Between, DNA β Satellites in Plants Inoculated with Tomato yellow leaf curl China virus and Tobacco curly shoot virus

Abstract

Tomato yellow leaf curl China virus (TYLCCNV) Y10 isolate (Y10) and Tobacco curly shoot virus (TbCSV) Y35 isolate (Y35), both obtained from Yunnan Province, were each found to be associated with a distinct species of satellite DNA (DNA beta). Here, we demonstrate that both Y10 DNA beta (Y10beta) and Y35 DNA beta (Y35beta) were stably trans-replicated by the noncognate Begomovirus, although the noncognate DNA beta accumulated in plants at a lower level than did the cognate DNA beta. In Nicotiana benthamiana and N. glutinosa plants agroinoculated with Y10+Y10beta+Y35beta or with Y35+Y35beta+Y10beta, all components accumulated in the early stages of infection but, at later stages, the noncognate DNA beta decreased in relative concentration and was undetectable at 80 to 120 days after inoculation. The helper viruses and cognate DNA beta species persisted at higher levels throughout the experiments. When the initiation codon of the betaC1 gene of the cognate DNA beta was mutated, the dominance of the cognate over the noncognate DNA beta in mixed infections was unimpaired. These results imply that the cognate DNA beta competes with the noncognate DNA beta and that the ability for selective maintenance of DNA beta is not controlled by the betaC1 protein.

A Novel DNA Motif Contributes to Selective Replication of a Geminivirus-Associated Betasatellite by a Helper Virus-Encoded Replication-Related Protein

“…Previous studies showed that TYLCCNV-Y10 and TbCSV-Y35 (referred to here as Y10 and Y35, respectively) preferentially maintain their cognate satellites, TYLCCNB and TbCSB (referred to here as Y10␤ and Y35␤, respectively). When Y10 or Y35 was coinoculated with Y10␤ and Y35␤ into N. benthamiana plants, the noncognate satellite relative to the helper virus was gradually lost at late stages of infection, while the cognate one was stably maintained (26). To determine the sequence element(s) that mediates maintenance selectivity, we partitioned the betasatellite genome into four regions, the right side of the SCR region (RCR), the ␤C1 coding region (C1), the promoter and A-rich region (AP), and the left side of the SCR region (LCR) (Fig.…”

“…DNA gel blot analysis was performed as described previously (26). The DNA probes were produced by PCR amplification using specific primer pairs, probe Y10␤-AP for Y10␤, Y10␤-35RCR, Y10␤-35␤C1, Y10␤-35LCR, Y10␤-35RBM, and Y10␤-delRBM, probe Y35␤-AP for Y35␤, Y35␤-10RCR,Y35␤-10␤C1, Y35␤-10LCR, Y35␤-10RBM, and Y35␤-del-RBM, probe Y10␤-␤C1 for Y10␤ and Y10␤-35AP, and probe Y35␤-␤C1 for Y35␤ and Y35␤-10AP.…”

“…However, when both betasatellite molecules were coinoculated with one helper virus, the cognate betasatellite predominated over the noncognate one. At late stages of the infection, the noncognate betasatellite became undetectable in the new leaves of inoculated plants (26). So far, little is known about the molecular mechanisms of betasatellite replication, and the sequence elements conferring promiscuous yet differential replication remain uncharacterized.…”

Cotton leaf curl Multan betasatellite as a plant gene delivery vector trans-activated by taxonomically diverse geminiviruses

“…Betasatellite replication and encapsidation in host plants depends on the presence of helper viruses. Recently, it has been demonstrated that betasatellites from a diverse range of sources can be stably trans-replicated by non-cognate begomoviruses [13,33,40,45]. The replication of CLCuMB is supported by four distinct cotton-infecting monopartite begomoviruses [37] and also TLCV-Au [49].…”

First report of tobacco curly shoot virus infecting Malvastrum coromandelianum in China

“…Then a fragment of ca. 1.0 kb was obtained from two (SC776 and GX121) of the 26 samples using TbCSV specific primers Y35F1/Y35 + 10R (Qing and Zhou 2009). Sequence alignment showed the h i g h e s t i d e n t i t y w i t h i s o l a t e T b C S V-[ C h i n a : Sichuan118:2009], 99.5 and 99.7%, respectively.…”