Mohr Peter G, Moody Nicholas J G, Williams Lynette M, Hoad John, St J Crane Mark
CSIRO Australian Animal Health Laboratory, 5 Portarlington Rd, East Geelong, Victoria 3220, Australia.
Dis Aquat Organ. 2015 Sep 17;116(1):1-9. doi: 10.3354/dao02903.
Tasmanian aquabirnaviruses (TABVs) have been isolated intermittently since 1998 from healthy Atlantic salmon Salmo salar and rainbow trout Oncorhynchus mykiss farmed in Macquarie Harbour, Tasmania, Australia. However, beginning in 2011, TABVs have been isolated from rainbow trout in association with mortality events. To determine if recent molecular changes in TABV were contributing to increased mortalities, next generation sequencing was undertaken on 14 TABVs isolated from 1998 to 2013. Sequencing of both genome segments and analysis of the 5 viral proteins they encode revealed that minimal changes had occurred in the past 15 yr. Of the amino acid changes detected only 1, alanine to aspartic acid at position 139 of the minor structural VP3 protein, was unique to the recent disease events. The most dramatic changes observed were in the length of the non-structural VP5 protein varying from 43 to 133 amino acids. However, the amino acid substitution in VP3 and variable VP5 length were unlikely to have resulted in increased TABV pathogenicity. The genome of a novel Australian aquabirnavirus, Victorian trout aquabirnavirus (VTAB) was also sequenced and compared to TABV isolates.
自1998年以来，澳大利亚塔斯马尼亚州麦夸里港养殖的健康大西洋鲑鱼（Salmo salar）和虹鳟鱼（Oncorhynchus mykiss）中曾间歇性分离出塔斯马尼亚水生双RNA病毒（TABV）。然而，从2011年开始，在虹鳟鱼死亡事件中分离出了TABV。为了确定TABV最近的分子变化是否导致死亡率增加，对1998年至2013年间分离出的14株TABV进行了二代测序。对两个基因组片段进行测序，并分析它们编码的5种病毒蛋白，结果显示在过去15年中发生的变化极小。在检测到的氨基酸变化中，只有次要结构蛋白VP3第139位的丙氨酸变为天冬氨酸这一变化是近期疾病事件所特有的。观察到的最显著变化是在非结构蛋白VP5的长度上，其长度从43个氨基酸到133个氨基酸不等。然而，VP3中的氨基酸替换和VP5长度的变化不太可能导致TABV致病性增加。还对一种新的澳大利亚水生双RNA病毒——维多利亚鳟鱼水生双RNA病毒（VTAB）的基因组进行了测序，并与TABV分离株进行了比较。
