Virus isolate G6 was obtained from Hibiscus rosa-sinensis showing yellow and leaf curl symptoms in Guangzhou, Guangdong Province. The complete nucleotide sequence of DNA-A was determined to be 2 737 nucleotides encoding six potential ORFs. Comparison showed that G6 DNA-A had more than 89% sequence identify with all isolates of Cotton leaf curl Multan virus (CLCuMV) and shared the highest sequence identify (96.1%) with CLCuMV isolate 62. G6 DNA-A had 87.1%-89.8% sequence identity with those of CLCuRV isolates, while less than 87% identities with other begomoviruses. Phylogenetic analysis of G6 DNA-A and selected begomoviruses showed that G6 was most closely related to CLCuMV isolates, and they clustered together as a separate branch. Satellite DNA molecule (G6 DNAbeta) was found to be associated with G6 using the primers beta01 and beta02. G6 DNAbeta contains 1346 nucleotides, with a potential functional ORF (C1) in complementary sense DNA. Pairwise comparison indicated that G6 DNAbeta had the highest sequence identities with CLCuMV DNAbeta (92.1%) and CLCuRV DNAbeta (88.7%), but less than 80% sequence identities with other reported satellite DNA molecules. Phylogenetic analysis indicated that G6 DNAbeta was most closely related to CLCuMV DNAbeta and the two DNAbetas clustered together as a separate branch, and formed the main branch with DNAbeta of CLCuRV and MYVV-Y47. It is concluded that G6 infecting Hibiscus rosa-sinensis is an isolate of CLCuMV.
Base Sequence ; DNA, Satellite ; chemistry ; DNA, Viral ; chemistry ; Geminiviridae ; classification ; genetics ; Gossypium ; virology ; Hibiscus ; virology ; Phylogeny

An increasing number of monopartite begomoviruses are being identified that a satellite molecule (DNAbeta) is required to induce typical symptoms in host plants. DNAbeta encodes a single gene (termed betaC1) encoded in the complementary-sense. We have produced transgenic Nicotiana benthamiana and N. tabacum plants expressing the betaC1 gene of a DNAbeta associated with Tomato yellow leaf curl China virus (TYLCCNV), under the control of the Cauliflower mosaic virus 35S promoter. Transgenic plants expressing betaC1 showed severe developmental abnormalities in both species. Microscopic analysis of sections of both transgenic and non-transgenic N. tabacum leaves showed abnormal outgrowths of transgenic N. tabacum to be due to disorganized cell division (hyperplasia) of spongy and palisade parenchyma. Immuno-gold labeling of sections with a polyclonal antibody against the betaC1 protein showed that the betaC1 protein accumulated in the nuclei of cells. The possible biological function of the betaC1 protein was discussed.
Cell Division ; physiology ; Cell Nucleus ; genetics ; metabolism ; ultrastructure ; Cells, Cultured ; DNA, Viral ; genetics ; Geminiviridae ; genetics ; Plant Diseases ; genetics ; virology ; Plant Leaves ; cytology ; genetics ; growth & development ; metabolism ; Plants, Genetically Modified ; growth & development ; metabolism ; Recombinant Proteins ; metabolism ; Tobacco ; cytology ; growth & development ; metabolism ; ultrastructure ; Viral Proteins ; genetics ; metabolism

Begomoviruses are single-stranded DNA viruses and cause severe diseases in major crop plants worldwide. Based on current genome sequence analyses, we found that synonymous codon usage variations in the protein-coding genes of begomoviruses are mainly influenced by mutation bias. Base composition analysis suggested that the codon usage bias of AV1 and BV1 genes is significant and their expressions are high. Fourteen codons were determined as translational optimal ones according to the comparison of codon usage patterns between highly and lowly expressed genes. Interestingly the codon usages between begomoviruses from the Old and the New Worlds are apparently different, which supports the idea that the bipartite begomoviruses of the New World might originate from bipartite ones of the Old World, whereas the latter evolve from the Old World monopartite begomoviruses.
Begomovirus ; genetics ; Biological Evolution ; Chromosome Mapping ; Codon ; genetics ; DNA Mutational Analysis ; DNA, Viral ; genetics ; Evolution, Molecular