Ndowora T, Dahal G, LaFleur D, Harper G, Hull R, Olszewski N E, Lockhart B
Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, 55108, USA.
Virology. 1999 Mar 15;255(2):214-20. doi: 10.1006/viro.1998.9582.
When some virus- and disease-free Musa spp. (banana and plantain) are propagated by tissue culture, the resulting plants develop infections with banana streak badnavirus (BSV), a pararetrovirus. In sharp contrast to the virion DNA recovered from natural infections, the virion DNA from tissue culture-associated infections of different Musa spp. was highly similar if not identical. Although BSV does not employ integration during the infection cycle, BSV DNA was found to be integrated into the Musa genome. While one integration consisted of a partial BSV genome, a second contained more than one complete genome that was almost identical to BSV recovered from tissue culture-derived plants. The arrangement of this integrated BSV DNA suggests that it can yield an infectious episomal genome via homologous recombination. This report documents the first instance of integrated DNA of a nonintegrating virus giving rise to an episomal viral infection and identifies tissue culture as a possible trigger for the infection, raising the question of whether similar activatable viral sequences exist in the genomes of other plants and animals.
当一些无病毒和疾病的芭蕉属植物（香蕉和大蕉）通过组织培养进行繁殖时，所产生的植株会感染香蕉条纹杆状病毒（BSV），一种准逆转录病毒。与从自然感染中回收的病毒粒子DNA形成鲜明对比的是，来自不同芭蕉属植物组织培养相关感染的病毒粒子DNA即使不完全相同也高度相似。尽管BSV在感染周期中不进行整合，但发现BSV DNA已整合到芭蕉属基因组中。其中一次整合包含部分BSV基因组，另一次整合则包含多个与从组织培养衍生植物中回收的BSV几乎相同的完整基因组。这种整合的BSV DNA的排列表明它可以通过同源重组产生一个感染性的附加型基因组。本报告记录了非整合病毒的整合DNA引发附加型病毒感染的首例情况，并确定组织培养是感染的一个可能触发因素，这就提出了一个问题，即其他植物和动物的基因组中是否存在类似的可激活病毒序列。
