Szego Anita, Enünlü Natalya, Deshmukh Sachin D, Veliceasa Dorina, Hunyadi-Gulyás Eva, Kühne Thomas, Ilyés Pál, Potyondi László, Medzihradszky Katalin, Lukács Noémi
Department of Plant Physiology and Plant Biochemistry, Corvinus University of Budapest, Ménesi út 44, 1118 Budapest, Hungary.
Virus Genes. 2010 Apr;40(2):267-76. doi: 10.1007/s11262-009-0432-4.
This study determined the complete nucleotide sequence of Beet cryptic virus 1 (BCV1). As expected by analogy to previously sequenced alphacryptoviruses, dsRNA1 (2008 bp) encodes a 72.5-kDa protein containing sequence motifs characteristic for RNA-dependent RNA polymerases (RdRp). In addition to the full-length dsRNA1, a truncated form was also detected in dsRNA extracts. dsRNA2 (1783 bp) codes for the viral coat protein (CP) as proven by the identity of the predicted CP sequence to peptide sequences of the purified virion protein. The amino acid sequence of BCV1 RdRp as well as the 5'- and 3'-UTRs show 81-85% identity to the corresponding regions of Vicia cryptic virus (VCV), White clover cryptic virus 1 (WCCV1) and Carrot cryptic virus (CaCV). The amino acid sequence identity of the CP is about 55-62%, moreover, a strong conservation of predicted alpha-helical regions was observed. The high degree of similarity of these seed- and pollen-transmitted viruses persisting in phylogenetically distant hosts, together with their high similarity to fungal partitiviruses strongly supports the hypothesis that horizontal transfer by a fungus played a role in the emergence of the present cryptovirus species. The change in the distribution of cryptic viruses may also be due to human influence: While earlier BCV1 occurred frequently in sugar beet cultivars, it is very rare in cultivars currently used in agricultural practice and was detected in only one of the 28 cultivars investigated in our experiments.
The online version of this article (doi:10.1007/s11262-009-0432-4) contains supplementary material, which is available to authorized users.
本研究确定了甜菜隐性病毒1（BCV1）的完整核苷酸序列。正如通过与先前测序的α隐性病毒类比所预期的那样，双链RNA1（2008 bp）编码一种72.5 kDa的蛋白质，该蛋白质含有RNA依赖的RNA聚合酶（RdRp）的特征序列基序。除了全长双链RNA1外，在双链RNA提取物中还检测到一种截短形式。双链RNA2（1783 bp）编码病毒外壳蛋白（CP），这通过预测的CP序列与纯化的病毒粒子蛋白的肽序列的一致性得到证实。BCV1 RdRp的氨基酸序列以及5'-和3'-非翻译区与蚕豆隐性病毒（VCV）、白三叶草隐性病毒1（WCCV1）和胡萝卜隐性病毒（CaCV）的相应区域显示出81 - 85%的同一性。CP的氨基酸序列同一性约为55 - 62%，此外，还观察到预测的α螺旋区域有很强的保守性。这些存在于系统发育上遥远宿主中的通过种子和花粉传播的病毒的高度相似性，以及它们与真菌双分体病毒的高度相似性，有力地支持了这样一种假说，即真菌介导的水平转移在当前隐性病毒物种的出现中起了作用。隐性病毒分布的变化也可能是由于人类的影响：虽然早期BCV1在甜菜品种中频繁出现，但在目前农业实践中使用的品种中非常罕见，并且在我们实验中调查的28个品种中仅在一个品种中检测到。
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