Molecular Characterization of Cotton leaf curl Multan virus and the Associated Satellite DNA Infecting Okra in Guangdong

The virus isolate Okra06 was obtained from the diseased okra plants exhibiting yellow vein and leaf curl symptoms in Guangzhou, Guangdong Province. The results of PCR detection indicated that the virus belonged to the genus Begomovirus of the family Geminiviridae. The genome of the virus was cloned and sequenced. The results showed that it had only A component（DNA-A）. The complete nucleotide sequence of DNA-A was determined to be 2 737 nucleotides, encoding six potential ORFs. The comparison showed that Okra06 DNA-A had the highest nucleotide sequence identity (99.7%) with CLCuMV-［G6］. Six ORFs shared 100%, 100%, 99.6%, 99.8%, 100% and 99.7% nucleotide sequence identities with CLCuMV–［G6］, respectively. The Okra06 was also associated with satellite DNA β molecular. The full-length sequence of DNA β was determined to be 1 346 nucleotides, encoding one potential ORF (C1). The comparison further showed that Okra06 DNA β had the highest nucleotide sequence identity(99.5%)with G6 DNA β. Phylogenetic analysis revealed that DNA β of isolate Okra06, G6 and Gx08 were more closely related than the other begomoviruses associated with DNA β, and were clustered in a separate branch and further clustered with other isolates of CLCuMV DNA β or CLCuV DNA β. Those results revealed that the virus isolate Okra06 infecting okra plants in Guangdong belonged to the species CLCuMV, and it should be the Hibiscus strain.