Verhoeven J Th J, Jansen C C C, Botermans M, Roenhorst J W
Plant Protection Service, P.O. Box 9102, 6700 HC Wageningen, the Netherlands.
Plant Dis. 2010 Jul;94(7):920. doi: 10.1094/PDIS-94-7-0920C.
In 2008, in the framework of surveying for pospiviroids, nine symptomless clones of Celosia plumosa (Voss) Burv. (Amaranthaceae) from a Dutch breeding company were tested by reverse transcription (RT)-PCR with primer sets Pospi1-RE/FW and Vid-RE/FW (4). In four samples, amplicons of 227 nt were obtained with primers Pospi1-RE/FW. Sequencing of the amplicons showed identities of more than 99% to the partial sequence of Iresine viroid 1 (IrVd-1) from Alternanthera sessilis, NCBI GenBank Accession No DQ846886 (2). Subsequently, a set of primers was designed to amplify the complete viroid genome, i.e., IrVd-FW1 5'-GCG GAA GAA ACA GGA GCT CGW CT-3' and IrVd-RE1 5'-CGC GWG GAG TTC TCC GGT CTT TA-3' - identical to nt 168 to 190 and 145 to 167 of the complete IrVd-1 sequences in the NCBI GenBank (Nos. DQ094293, DQ094294, NC_003613, and X95734). One isolate from C. plumosa was amplified with this primer pair and amplicons were cloned into the pGEM-T Easy Vector System II. Sequencing of one individual cDNA clone (GenBank Accession No. GU911350) revealed a genome size of 370 nt and 98.1% sequence identity to the IrVd-1 isolate from Vinca major, GenBank Accession No. DQ094293 (1). Hence, the viroid was identified as IrVd-1. The isolate from C. plumosa was also mechanically inoculated to 10 healthy plants of C. plumosa, chrysanthemum (Chrysanthemum × morifolium) cv. White Delianne, potato (Solanum tuberosum) cv. Nicola, and tomato (Solanum lycopersicum) cv. Moneymaker. No symptoms were observed over a 6-week period, and RT-PCR with primers Pospi1-RE/FW on bulked samples of five plants per species only identified IrVd-1 in both samples of C. plumosa. For tomato, these results confirm those of Spieker (3). Therefore, in contrast to the other pospiviroids, it seems unlikely that IrVd-1 poses a threat to potato and tomato. References: (1) X. Nie et al. Can. J. Plant Pathol. 27:592, 2005. (2) R. P. Singh et al. Plant Dis. 90:1457, 2006. (3) R. L. Spieker. J. Gen. Virol. 77:2631, 1996. (4) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 110:823, 2004.
2008年，在对马铃薯纺锤块茎类病毒进行检测的框架下，利用引物对Pospi1 - RE/FW和Vid - RE/FW（4），通过逆转录（RT）- PCR对一家荷兰育种公司的9个无症状的羽状鸡冠花（Voss）Burv.（苋科）克隆进行了检测。在4个样品中，使用引物Pospi1 - RE/FW获得了227 nt的扩增子。扩增子测序显示，其与来自节节菜的假酸浆子叶类病毒1（IrVd - 1）的部分序列（NCBI GenBank登录号DQ846886）的同一性超过99%（2）。随后，设计了一组引物来扩增完整的类病毒基因组，即IrVd - FW1 5'-GCG GAA GAA ACA GGA GCT CGW CT - 3'和IrVd - RE1 5'-CGC GWG GAG TTC TCC GGT CTT TA - 3' - 与NCBI GenBank中完整IrVd - 1序列（登录号DQ094293、DQ094294、NC_003613和X95734）的第168至190位核苷酸和第145至167位核苷酸相同。用该引物对扩增了一个来自羽状鸡冠花的分离株，并将扩增子克隆到pGEM - T Easy Vector System II中。对一个个体cDNA克隆（GenBank登录号GU911350）的测序显示，基因组大小为370 nt，与来自长春花的IrVd - 1分离株（GenBank登录号DQ094293）的序列同一性为98.1%（1）。因此，该类病毒被鉴定为IrVd - 1。来自羽状鸡冠花的分离株也通过机械接种到10株健康的羽状鸡冠花、菊花（菊花×morifolium）品种White Delianne、马铃薯（茄属）品种Nicola和番茄（茄属）品种Moneymaker上。在6周的时间内未观察到症状，并且使用引物Pospi1 - RE/FW对每个物种的5株植物的混合样品进行RT - PCR检测，仅在羽状鸡冠花的两个样品中鉴定出IrVd - 1。对于番茄，这些结果证实了Spieker的结果（3）。因此，与其他马铃薯纺锤块茎类病毒相比，IrVd - 1似乎不太可能对马铃薯和番茄构成威胁。参考文献：（1）X. Nie等人，《加拿大植物病理学杂志》27:592，2005年。（2）R. P. Singh等人，《植物病害》90:1457，2006年。（3）R. L. Spieker，《普通病毒学杂志》77:2631，1996年。（4）J. Th. J. Verhoeven等人，《欧洲植物病理学杂志》110:823，2004年。
