Sequence analysis of CP and HC-Pro genes of Turnip mosaic virus isolates from China.

- Fourteen isolates of Turnip mosaic virus (TuMV) were obtained from the leaves of diseased cruciferous plants in China. According host tests, the isolates were classified into B-host and BR-host group. The nucleotide sequences of the coat protein (CP) and helper component proteinase (HC-Pro) genes of the isolates were determined. The CP genes consisted of 864 nucleotides encoding a polypeptide of 288 amino acids. The HC-Pro genes comprised 1374 nucleotides encoding a polypeptide of 458 amino acids. The genes CP and HC-Pro of the 14 isolates shared nucleotide sequence identities ranging from 89.2 to 99.5% and 79.1 to 99.9%, respectively. Amino acid sequence identities of CP and HC-Pro proteins ranged from 95.1 to 100% and 94.8 to 99.8%, respectively. Phylogenetic tree based on the CP gene indicated that 13 of the 14 TuMV isolates belonged to the world-B group, while the remaining isolate ZJ1 belonged to the basal-BR group. The phylogenetic tree based on the HC-Pro gene was similar to that ofCP gene with the exception of the isolate JX that clustered with the Asian-BR group. Our results were consistent with the previous results demonstrating that a majority of the isolates collected from Brassica spp. belonged to the world-B group.