First Report of Citrus exocortis viroid from Grapevine in China

Citrus exocortis viroid (CEVd) can induce bark scaling, dwarfing, leaf epinasty, and fruit yield loss in susceptible hosts. In citrus, CEVd is reported from around the world, but in grape, it is reported from fewer locations (Australia, Brazil, California, and Spain [1]). In 2009, leaves were collected from 40 grapevines (of several different cultivars and species) from Henan, Hubei, Shandong, and Liaoning provinces, China. Total RNA or double-stranded RNA was extracted from the leaves by a described method (3) and subjected to reverse transcription with a random primer (Takara, Dalian, China) and then PCR with primer CEV-AM3 and CEV-AP3 (2). Results showed that the target DNA fragments of 372 bp long were amplified only from the symptomless leaves collected from two grapevines of cv. White Rose grown for approximately 26 years within a small garden in Hubei Province. Amplified products were recovered and cloned into pMD18-T (Takara) and 10 positive clones of each isolate were sequenced and aligned. For both isolates, 20% of the clones represented the same variant (CEVd-hn-g-1; GenBank Accession No. GU592444). It showed a max identity of 94 to 99% with the variants (GenBank Accession Nos. Y00328.1 and DQ471996.1) from grape registered in NCBI, 91 to 100% (GenBank Accession Nos. DQ431993.1 and DQ831485.1) from citrus, 91 to 98% (GenBank Accession Nos. EF488068.1 and EF488050.1) from broad bean, and 89 to 94% (GenBank Accession Nos. AY671953.1 and S67446.1) from tomato. To our knowledge, this is the first report of CEVd from grape in China. References: (1) M. Eiras et al. Fitopatol. Bras. 31:440, 2006. (2) H. J. Gross et al. Eur. J. Biochem. 121:249, 1982. (3) W. X. Xu et al. J. Virol. Methods 135:276, 2006.