[Molecular characterization of cotton leaf Curl Multan virus and its satellite DNA that infects Hibiscus rosa-sinensis].

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.

[Molecular characteristics of DNA-A of tomato leaf curl Guangdong virus isolate G2].

Virus isolate G2 was isolated from tomato plants showing leaf curl symptoms in Guangdong. The complete nucleotide sequence of G2 DNA-A was determined to be 2744 nucleotides encoding six potential ORFs, with two (AV1 and AV2) in virus sense and four (AC1, AC2, AC3 and AC4) in complementary sense. G2 DNA-A has a typical characteristics of Begomovirus genome organization. BLAST results showed that G2 DNA-A belonged to the Begomovirus of Geminiviridae. Pairwise comparisons of G2 DNA-A with those of other 41 begomoviruses indicated that G2 DNA-A was most closely related to that of Papaya leaf curl China virus isolate G10 (PaLCuCNV-[G10]) (82.8% sequence identity). The intergenic region (IR) of G2 differed to great extent with other begomoviruses (30.9%-81.8% nucleotide sequence identity); when individual encoded proteins were compared, the CP of G2 had relatively high amino acid sequence identity (77.6%-99.2%) with other begomoviruses whereas the AC4 of G2 had less amino acid sequence identity (43.5%-78.8%). Phylogenetic analysis based on the DNA-A sequences also showed that G2 was less related to the reported begomoviruses. These results revealed that G2 infecting Guangdong tomato might be a previously unreported species of Begomovirus, for which the name Tomato leaf curl Guangdong Virus (ToLCGDV) is proposed.