Molecular characterization of Tomato yellow leaf curl China virus and its satellite DNA isolated from tobacco

Virus isolates, Y8, Y36 and Y38, were obtained from tobacco plants showing leaf curl symptoms in Honghe, Yunnan Province. In reactions with 14 monoclonal antibodies raised against Begomovirus particles, Y8, Y36 and Y38 had similar antigenic reaction in TAS-ELISA as Tomato yellow leaf curl China virus (TYLCCNV). The complete DNA-A nucleotide sequences of Y8, Y36 and Y38 were determined and they contain 2727, 2730 and 2730 nucleotides, respectively. Each of the DNA-A sequences has a typical Begomovirus genome organization encoding 6 ORFs with 2 ORFs [AV1(CP) and AV2] in virion-sense DNA and 4 ORFs (AC1 to AC4) in complementary-sense DNA. Comparisons with total DNA-A, intergenic region and deduced amino acid sequences of individual ORFs show that Y8, Y36 and Y38 are isolates of TYLCCNV. Satellite DNA molecules (DNAP) were found to be associated with Y8, Y36 and Y38, which consist of 1338, 1339 and 1338 nucleotides, respectively. Comparisons show that these DNAbeta molecules share 98%-99% sequence identities on nucleotide level and have a common ORF (designated Cl) encoding 126 amino acids on the complementary strand.