Scheets Kay, Jordan Ramon, White K Andrew, Hernández Carmen
Department of Botany, 301 Physical Sciences, Oklahoma State University, Stillwater, OK, 74078-3013, USA,
Arch Virol. 2015 Sep;160(9):2385-93. doi: 10.1007/s00705-015-2500-5. Epub 2015 Jul 7.
Currently, the family Tombusviridae encompasses thirteen viral genera that contain single-stranded, positive-sense RNA genomes and isometric virions; the exception being the genus Umbravirus, whose members do not encode a coat protein (CP). A new genus, tentatively named Pelarspovirus, is proposed to be added to this family and would include five members, with Pelargonium line pattern virus recommended as the type species. Viruses assigned to this proposed genus have monopartite genomes encoding five open reading frames (ORFs) that include two 5'-proximal replication proteins, two centrally located movement proteins (MP1 and MP2) and a 3'-proximal CP that, at least for pelargonium line pattern virus (PLPV), has been shown to act also as suppressor of RNA silencing. Distinguishing characteristics of these viruses include i) production of a single, tricistronic subgenomic RNA for expression of MP and CP genes, ii) presence of a non-AUG start codon (CUG or GUG) initiating the MP2 ORF, iii) absence of AUG codons in any frame between the AUG initiation codons of MP1 and CP genes, and iv) sequence-based phylogenetic clustering of all encoded proteins in separate clades from those of other family members.
目前，番茄病毒科包含13个病毒属，这些病毒属含有单链正义RNA基因组和等轴对称病毒粒子；伞形病毒属除外，其成员不编码外壳蛋白（CP）。现提议在该科中增加一个新属，暂定名为天竺葵病毒属，该属将包括5个成员，推荐天竺葵线条花纹病毒作为模式种。归入该提议属的病毒具有单分体基因组，编码5个开放阅读框（ORF），其中包括两个位于5'端的复制蛋白、两个位于基因组中部的运动蛋白（MP1和MP2）以及一个位于3'端的CP，至少对于天竺葵线条花纹病毒（PLPV）而言，该CP也已被证明可作为RNA沉默抑制子。这些病毒的显著特征包括：i）产生单个三顺反子亚基因组RNA用于MP和CP基因的表达；ii）MP2 ORF起始于非AUG起始密码子（CUG或GUG）；iii）在MP1和CP基因的AUG起始密码子之间的任何读框中均不存在AUG密码子；iv）所有编码蛋白基于序列的系统发育聚类与其他科成员的聚类分属于不同分支。
