ABSTRACT
Ornamental perennial plants may serve as reservoirs for viruses that infect field crops. Duranta repens is an ornamental shrub that frequently exhibits leaf curl symptoms typical of begomoviral infection. Two begomoviruses or DNA-A components (isolates 57SA and 58SA) along with a DNA-B component (31SA) were identified in a symptomatic D. repens plant. Isolates 57SA and 58SA showed the highest nucleotide sequence identity of 90% and 92.2% to catharanthus yellow mosaic virus (CaYMV) and chilli leaf curl India virus (ChiLCINV), respectively, whereas 31SA shared the highest nucleotide sequence identity of 95.2% with the DNA-B component of tomato leaf curl New Delhi Virus (ToLCNDV). Isolate 57SA (showing < 91% highest nucleotide sequence identity) may thus be considered a member of a distinct species, and we propose the name "duranta leaf curl virus" (DLCV) for this virus. In addition, isolate 58SA (showing highest nucleotide sequence identity < 94%) is a newly identified strain of ChiLCINV for which the name "Duranta" strain is proposed. Further analysis showed that 57SA, 58SA and 31SA are recombinant, again highlighting the importance of recombination in begomovirus evolution. This is the first identification of DLCV. Also, a mixed infection with two viruses (or DNA-A components) and one DNA-B is reported.
Subject(s)
Begomovirus/genetics , DNA, Viral/genetics , Genome, Viral , Phylogeny , Verbenaceae/virology , Base Sequence , Begomovirus/classification , Begomovirus/isolation & purification , High-Throughput Nucleotide Sequencing , Pakistan , Plant Diseases/virology , Recombination, Genetic , Sequence Analysis, DNA , Sequence Homology, Nucleic AcidABSTRACT
The complete nucleotide sequence of the genomic RNA of the new virus Nemesia ring necrosis virus (NeRNV), which is widespread in various ornamental plant species belonging to the Scrophulariaceae and Verbenaceae, has been determined. Based on its gene content, the folding properties of its 5'-untranslated region and in vitro translation experiments, NeRNV RNA is a typical tymovirus RNA. Its 3' end, however, differs greatly from those of the valine-specific tymoviral RNAs that have been analysed previously. It can be folded into an upstream pseudoknot domain and a histidine-specific tRNA-like structure, a combination that, so far, has been found only in tobamoviral RNAs. The identity elements found in NeRNV RNA for recognition by yeast histidyl-tRNA synthetase are more similar to those of yeast tRNAHis than the ones found in tobacco mosaic virus RNA. As a result NeRNV RNA can be charged with histidine even more efficiently than tobacco mosaic virus RNA.
