USDA-ARS, Imported Fire Ant and Household Insects Research Unit, Gainesville, FL 32608, USA.
J Invertebr Pathol. 2010 Sep;105(1):105-11. doi: 10.1016/j.jip.2010.05.018. Epub 2010 Jun 1.
The RNA-dependent RNA polymerase (RdRp) region of Solenopsis invicta virus 1 (SINV-1) was sequenced from 47 infected colonies of S. invicta, S. richteri, S. geminata, and S. invicta/richteri hybrids collected from across the USA, northern Argentina, and northern Taiwan in an attempt to infer demographic information about the recent S. invicta introduction into Taiwan by phylogenetic analysis. Nucleotide sequences were calculated to exhibit an overall identity of >90% between geographically-separated samples. A total of 171 nucleotide variable sites (representing 22.4% of the region amplified) were mapped across the SINV-1 RdRp alignment and no insertions or deletions were detected. Phylogenetic analysis at the nucleotide level revealed clustering of Argentinean sequences, distinct from the USA sequences. Moreover, the SINV-1 RdRp sequences derived from recently introduced populations of S. invicta from northern Taiwan resided within the multiple USA groupings implicating the USA as the source for the recent introduction of S. invicta into Taiwan. Examination of the amino acid alignment for the RdRp revealed sequence identity >98% with only nine amino acid changes observed. Seven of these changes occurred in less than 4.3% of samples, while 2 (at positions 1266 and 1285) were featured prominently. Changes at positions 1266 and 1285 accounted for 36.2% and 34.0% of the samples, respectively. Two distinct groups were observed based on the amino acid residue at position 1266, Threonine or Serine. In cases where this amino acid was a Threonine, 90% of these sequences possessed a corresponding Valine at position 1285; only 10% of the Threonine(1266)-containing sequences possessed an Isoleucine at the 1285 position. Among the Serine(1266) group, 76% possessed an Isoleucine at position 1285, while only 24% possessed a Valine. Thus, it appears that the Threonine(1266)/Valine(1285) and Serine(1266)/Isoleucine(1285) combinations are predominant phenotypes.
从美国各地、阿根廷北部和中国台湾北部采集的 47 个感染的红火蚁、红火蚁/红火蚁杂交种、深红红火蚁和双齿多刺蚁群体中，对红火蚁病毒 1（SINV-1）的 RNA 依赖性 RNA 聚合酶（RdRp）区进行了测序，试图通过系统发育分析推断最近红火蚁引入台湾的人口统计学信息。核苷酸序列计算结果表明，地理上分离的样本之间的总体同一性>90%。在 SINV-1 RdRp 比对中总共映射了 171 个核苷酸可变位点（代表扩增区域的 22.4%），未检测到插入或缺失。核苷酸水平的系统发育分析显示，阿根廷序列聚类，与美国序列明显不同。此外，来自中国台湾北部的新近引入红火蚁群体的 SINV-1 RdRp 序列位于多个美国分组内，暗示美国是最近红火蚁引入台湾的来源。对 RdRp 的氨基酸比对进行检查，发现只有 9 个氨基酸发生变化，其序列同一性>98%。这 7 个变化发生在不到 4.3%的样本中，而另外 2 个（位置 1266 和 1285）则很明显。位置 1266 和 1285 的变化分别占样本的 36.2%和 34.0%。基于位置 1266 的氨基酸残基，观察到两个不同的组，苏氨酸或丝氨酸。在该氨基酸为苏氨酸的情况下，90%的这些序列在位置 1285 具有相应的缬氨酸；只有 10%的含有苏氨酸（1266）的序列在位置 1285 具有异亮氨酸。在丝氨酸（1266）组中，76%的序列在位置 1285 具有异亮氨酸，而只有 24%的序列具有缬氨酸。因此，苏氨酸（1266）/缬氨酸（1285）和丝氨酸（1266）/异亮氨酸（1285）组合似乎是主要表型。
