Molecular characterization of a partitivirus from Ophiostoma himal-ulmi
Molecular characterization of a partitivirus from Ophiostoma himal-ulmi
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DOI：
10.1007/s11262-005-0028-6
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发表时间：
2006-08-01
期刊：
影响因子：
1.6
通讯作者：
Buck, Kenneth W.
中科院分区：
文献类型：
--
作者：
Crawford, Lauren J.;Osman, Toba A. M.;Buck, Kenneth W.
测定了从喜马拉雅荷兰榆树病害真菌（Ophiostoma himal-ulmi）分离物HP 62中分离的两个双链（ds）RNA分子S1（1，744 bp）和S2（1，567 bp）的完整核苷酸序列。RNA S1具有编码539个氨基酸（62.7 kDa）的蛋白质P1的潜力，该蛋白质P1含有RNA依赖性RNA聚合酶（RdRps）的特征序列基序。数据库检索显示，P1与Partitivirus科Partitivirus属成员的RdRps密切相关。RNA S2具有编码430个氨基酸（46.3 kDa）的蛋白质P2的潜力，该蛋白质与Partitivirus属成员的衣壳蛋白相关。从分离株HP 62分离的病毒颗粒显示为直径为30 nm的等轴体，并且含有dsRNA S1和S2以及46 kDa的单个衣壳蛋白。来自衣壳蛋白的胰蛋白酶肽的N-末端测序明确地证明了它由RNA S2编码并且对应于蛋白P2。结论是O. himal-ulmi分离物HP 62含有一个新的分离病毒属成员，命名为Ophiostomapartitivirus 1。部分病毒科成员的RdRps系统发育树显示，目前至少有两个RdRp谱系的病毒被归类为部分病毒属。其中一个谱系包含真菌宿主的病毒和植物宿主的病毒，提高了植物和真菌之间水平传播partitivirus的可能性。分离病毒RdRp和衣壳蛋白似乎与衣壳蛋白平行进化，衣壳蛋白的进化比RdRp快得多。
The complete nucleotide sequences of two double-stranded (ds) RNA molecules, S1 (1,744 bp) and S2 (1,567 bp), isolated from an isolate HP62 of the Himalayan Dutch elm disease fungus, Ophiostoma himal-ulmi, were determined. RNA S1 had the potential to encode a protein, P1, of 539 amino acids (62.7 kDa), which contained sequence motifs characteristic of RNA-dependent RNA polymerases (RdRps). A database search showed that P1 was closely related to RdRps of members of the genus Partitivirus in the family Partitiviridae. RNA S2 had the potential to encode a protein, P2, of 430 amino acids (46.3 kDa), which was related to capsid proteins of members of the genus Partitivirus. Virus particles isolated from isolate HP62 were shown to be isometric with a diameter of 30 nm, and to contain dsRNAs S1 and S2 and a single capsid protein of 46 kDa. N-terminal sequencing of tryptic peptides derived from the capsid protein proved unequivocally that it is encoded by RNA S2 and corresponds to protein P2. It is concluded that O. himal-ulmi isolate HP62 contains a new member of the genus Partitivirus, which is designated Ophiostoma partitivirus 1. A phylogenetic tree of RdRps of members of the family Partitiviridae showed that there are least two RdRp lineages of viruses currently classified in the genus Partitivirus. One of these lineages contained viruses with fungal hosts and viruses with plant hosts, raising the possibility of horizontal transmission of partitiviruses between plants and fungi. The partitivirus RdRp and capsid proteins appear to have evolved in parallel with the capsid proteins evolving much faster than the RdRps.