Laboratory of Plant Virology, Department of Plant Pathology, College of Plant Protection, Shandong Agricultural University, Tai'an, 271018, Shandong, China.
Arch Virol. 2013 Dec;158(12):2505-15. doi: 10.1007/s00705-013-1766-8. Epub 2013 Jun 27.
Rice black-streaked dwarf virus (RBSDV) is a double-stranded RNA (dsRNA) virus belonging to the genus Fijivirus in the family Reoviridae. The genome of RBSDV consists of ten dsRNA segments. Although RBSDV has caused significant economic losses to rice and maize production in the past few years in China, its molecular diversity and evolution remain largely unknown. To elucidate the factor(s) underlying the evolution of RBSDV, we determined segment 8 (S8; carrying ORF8 encoding the minor core capsid protein) sequences of 101 samples and segment 10 (S10; carrying ORF10 encoding the major capsid protein) sequences of 103 samples. The results show that both ORF8 and ORF10 are under negative selection. The S8 of three isolates and S10 of two isolates are recombinants. The RBSDV population in China can be classified into three groups according to S8 sequences or into two groups according to S10 sequences, irrespective of host or geographical origin. Of the RBSDV isolates with both S8 and S10 sequences available, 17 are between-group reassortants and 30 are between-subgroup reassortants. The RBSDV subpopulations from different geographical regions and hosts show frequent gene flow within or between subpopulations. The RBSDV population from maize is in a state of expansion. In this study, no new emergent population was detected. Taken together, the results indicate that, in addition to recombination and negative selection, reassortment and gene flow are important factors that drive evolution of RBSDV in China.
水稻黑条矮缩病毒（Rice black-streaked dwarf virus，RBSDV）是一种双链 RNA（double-stranded RNA，dsRNA）病毒，属于呼肠孤病毒科斐济病毒属。RBSDV 的基因组由 10 个 dsRNA 片段组成。尽管 RBSDV 在过去几年中对中国的水稻和玉米生产造成了重大的经济损失，但它的分子多样性和进化仍知之甚少。为了阐明 RBSDV 进化的因素，我们测定了 101 个样本的第 8 片段（携带编码次要核心衣壳蛋白的 ORF8）和 103 个样本的第 10 片段（携带编码主要衣壳蛋白的 ORF10）序列。结果表明，ORF8 和 ORF10 都受到负选择。三个分离株的 S8 和两个分离株的 S10 是重组体。根据 S8 序列，中国的 RBSDV 群体可分为三组，或根据 S10 序列分为两组，而与宿主或地理来源无关。在具有 S8 和 S10 序列的 RBSDV 分离株中，有 17 个是组间重组体，有 30 个是亚组间重组体。来自不同地理区域和宿主的 RBSDV 亚群在亚群内或亚群间频繁发生基因流。来自玉米的 RBSDV 群体处于扩张状态。在本研究中，未检测到新的新兴群体。综上所述，结果表明，除了重组和负选择外，重配和基因流也是驱动中国 RBSDV 进化的重要因素。
