de Kochko A, Verdaguer B, Taylor N, Carcamo R, Beachy R N, Fauquet C
ILTAB/ORSTOM-TSRI, Scripps Research Institute, Division of Plant Biology, La Jolla, California, USA.
Arch Virol. 1998;143(5):945-62. doi: 10.1007/s007050050344.
The complete sequence of 8159 nucleotides of the double stranded DNA genome of cassava vein mosaic virus (CsVMV) was determined (# U59751) and revealed a significant difference in genome organization when compared with a previous report (# U20341). When transferred to cassava plants by microbombardment, the full length CsVMV clone was infectious, confirming the genome organization here described. Sequence comparisons between CsVMV and members of the genera Caulimovirus and Badnavirus revealed high homologies between consensus sequences of several proteins that are indispensable for virus replication, including a potential transactivator factor not reported previously. The presence of a sequence complementary to a plant Met tRNA confirms that CsVMV is a plant pararetrovirus and is most closely related to members of the genus Caulimovirus as previously assessed. However, differences in genome organization, number and size of the ORFs, in addition to sequence comparisons with other plant pararetroviruses, shows that either the genetic variability of caulimoviruses is much greater than previously thought, or that CsVMV is the unique representative of a new genus within the Caulimoviridae family. On the basis of this study, it is proposed to upgrade the floating genus Caulimovirus to the family level and to divide the Caulimoviridae family into at least three genera with CsVMV being the type member of a new genus.
木薯叶脉花叶病毒（CsVMV）双链DNA基因组8159个核苷酸的完整序列已被测定（登录号U59751），与之前的报道（登录号U20341）相比，其基因组结构存在显著差异。通过微弹轰击法将全长CsVMV克隆导入木薯植株后具有感染性，证实了此处所描述的基因组结构。CsVMV与花椰菜花叶病毒属和杆状DNA病毒属成员之间的序列比较显示，几种对病毒复制不可或缺的蛋白质的共有序列之间具有高度同源性，包括一种此前未报道过的潜在反式激活因子。存在与植物甲硫氨酸tRNA互补的序列，证实CsVMV是一种植物类逆转录病毒，并且如先前评估的那样，与花椰菜花叶病毒属成员关系最为密切。然而，基因组结构、开放阅读框的数量和大小的差异，以及与其他植物类逆转录病毒的序列比较表明，要么花椰菜花叶病毒的遗传变异性比之前认为的要大得多，要么CsVMV是花椰菜花叶病毒科内一个新属的唯一代表。基于这项研究，建议将花椰菜花叶病毒这个浮动属提升到科的级别，并将花椰菜花叶病毒科至少分为三个属，其中CsVMV是一个新属的模式成员。
