Stenger D C
Department of Biological Sciences, Northern Illinois University, DeKalb 60115.
Virology. 1994 Sep;203(2):397-402. doi: 10.1006/viro.1994.1501.
Transgenic Nicotiana benthamiana plants have been constructed which bear integrated, tandemly repeated copies of a beet curly top virus (BCTV) defective-interfering (DI) DNA derived from the Logan strain. Transgenic DI-DNA plant lines challenge-inoculated with BCTV-Logan exhibited delayed and attenuated symptoms compared to nontransgenic plants. Infection of transgenic plants with the Logan strain resulted in the mobilization of the integrated DI-DNA sequence, which was subsequently amplified as an episome. The accumulation of Logan helper virus DNA forms was reduced in transgenic plants, relative to nontransgenic plants. In contrast, no delay or attenuation of symptoms was observed for transgenic plants challenge-inoculated with the BCTV strains CFH and Worland. Infection by the CFH and Worland strains did not result in mobilization or amplification of the integrated Logan DI-DNA sequence, and no consistent differences in the accumulation of CFH or Worland genomic viral DNA forms were observed among transgenic and nontransgenic plants. These results, and a comparison of putative DNA replication origin sequences, suggest that BCTV strains display specificity with respect to recognition of heterologous DNA replication origin cis-elements.
已构建出携带源自洛根株系的甜菜曲顶病毒（BCTV）缺陷干扰（DI）DNA整合串联重复拷贝的转基因本氏烟草植株。与非转基因植株相比，用BCTV - 洛根株系进行挑战接种的转基因DI - DNA植株系表现出延迟和减轻的症状。用洛根株系感染转基因植株导致整合的DI - DNA序列移动，随后其作为附加体被扩增。相对于非转基因植株，转基因植株中洛根辅助病毒DNA形式的积累减少。相比之下，用BCTV株系CFH和沃兰进行挑战接种的转基因植株未观察到症状延迟或减轻。CFH和沃兰株系的感染未导致整合的洛根DI - DNA序列移动或扩增，并且在转基因和非转基因植株之间未观察到CFH或沃兰基因组病毒DNA形式积累的一致差异。这些结果以及对推定的DNA复制起始序列的比较表明，BCTV株系在识别异源DNA复制起始顺式元件方面表现出特异性。
