First report of Coleus blumei viroid 2 from commercial coleus in China.

Coleus (Coleus blumei) is an ornamental plant that is susceptible to infection by several viroids of the genus Coleviroid, which is a member of the family Pospiviroidae. Coleus blumei viroid (CbVd) -1 was first reported in commercial yellow coleus fields in Brazil in 1989 (1). In addition, CbVd-2, CbVd-3, and CbVd-4 have only been detected from coleus in Germany in 1996 (4). CbVd-5 and CbVd-6 were recently identified in China (2). In March 2010, leaves were collected from 50 symptomless coleus plants from a commercial nursery in Hainan Province, China. Total RNA was extracted from the leaves (3). Reverse transcription (RT)-PCR using CbVd-2 specific primers (forward: 5′-AGCTTACCTGGGTTCCCT-3′ and reverse: 5′-CTCTCCTCTATTTACTCTCTTCTC-3′) corresponding to positions 76 to 93 and 52 to 75 on the CbVd-2 reference sequence, respectively (GenBank Accession No. NC003682). Amplification of a 301-bp product was obtained from one sample. This PCR product was then cloned into pMD18-T (Takara, Dalian, China). Twelve pos...