Hamm J J, Styer E L, Federici B A
Insect Biology and Population Management Research Laboratory, USDA-ARS, Tifton, Georgia, 31793-0748, USA.
J Invertebr Pathol. 1998 Sep;72(2):138-46. doi: 10.1006/jipa.1998.4763.
Six field-collected ascovirus isolates obtained from five noctuid species in the continental United States were compared with respect to the general relatedness of their DNA, host range, and histopathology. Two isolates were from Spodoptera frugiperda, and the other four were from Autographa precationis, Heliothis virescens, Helicoverpa zea, and Trichoplusia ni. DNA-DNA hybridization studies showed that the six isolates belonged to three distinct viral species, with the isolates from S. frugiperda composing one species, those from A. precationis and H. virescens a second species, and those from H. zea and T. ni a third species. The host range and histopathology of each isolate was studied in eight noctuid species, S. frugiperda, Spodoptera ornithogalli, Spodoptera exigua, Spodoptera eridania, H. virescens, H. zea, A. precationis, and Feltia subterranea. Though some variation existed between the different isolates of each viral species, distinct patterns were apparent for each. The viral species from S. frugiperda had a host range that was limited primarily to Spodoptera species and both isolates of this virus only replicated and caused significant pathology in the fat body, whereas the viral species from A. precationis and H. virescens had a much broader host range that included most of the species tested, but also had a tissue tropism primarily restricted to the fat body. The viral species from T. ni and H. zea readily infected all the hosts tested, where the principal site of replication and significant pathology was the epidermis. In many test hosts, however, this viral species also replicated and caused significant pathology in the tracheal epithelium and to a lesser extent in the fat body. Aside from contributing to knowledge of ascovirus biology, these studies indicate that DNA hybridization profiles combined with studies of host range and tissue tropism can be used as characters for defining ascovirus species.
对从美国大陆的五种夜蛾科物种中分离得到的六种野外采集的 ascovirus 毒株进行了 DNA 一般相关性、宿主范围和组织病理学方面的比较。其中两种毒株来自草地贪夜蛾，另外四种分别来自苜蓿银纹夜蛾、烟芽夜蛾、棉铃虫和粉纹夜蛾。DNA-DNA 杂交研究表明，这六种毒株属于三个不同的病毒物种，草地贪夜蛾的毒株为一个物种，苜蓿银纹夜蛾和烟芽夜蛾的毒株为第二个物种，棉铃虫和粉纹夜蛾的毒株为第三个物种。在八种夜蛾科物种（草地贪夜蛾、食叶夜蛾、甜菜夜蛾、南美玉米夜蛾、烟芽夜蛾、棉铃虫、苜蓿银纹夜蛾和地老虎）中研究了每种毒株的宿主范围和组织病理学。尽管每个病毒物种的不同毒株之间存在一些差异，但每种毒株都有明显的模式。草地贪夜蛾的病毒物种宿主范围主要限于夜蛾属物种，该病毒的两种毒株仅在脂肪体中复制并引起明显病变，而苜蓿银纹夜蛾和烟芽夜蛾的病毒物种宿主范围更广，包括大多数测试物种，但其组织嗜性主要限于脂肪体。粉纹夜蛾和棉铃虫的病毒物种很容易感染所有测试宿主，其主要复制部位和明显病变部位是表皮。然而，在许多测试宿主中，这种病毒物种也在气管上皮中复制并引起明显病变，在脂肪体中的病变程度较轻。除了有助于了解 ascovirus 生物学外，这些研究表明，DNA 杂交图谱结合宿主范围和组织嗜性研究可作为定义 ascovirus 物种的特征。
