Phytopathology. 1999 Nov;89(11):1022-7. doi: 10.1094/PHYTO.1999.89.11.1022.
ABSTRACT Rice tungro disease is caused by rice tungro bacilliform virus (RTBV), which is responsible for the symptoms, and rice tungro spherical virus (RTSV), which assists transmission of both viruses by leafhoppers. Transgenic japonica rice plants (Oryza sativa) were produced containing the RTSV replicase (Rep) gene in the sense or antisense orientation. Over 70% of the plants contained one to five copies of the Rep gene, with integration occurring at a single locus in most cases. Plants producing antisense sequences exhibited significant but moderate resistance to RTSV (60%); accumulation of antisense RNA was substantial, indicating that the protection was not of the homology-dependent type. Plants expressing the full-length Rep gene, as well as a truncated Rep gene, in the (+)-sense orientation were 100% resistant to RTSV even when challenged with a high level of inoculum. Accumulation of viral RNA was low, leading us to conclude that RTSV Rep-mediated resistance is not protein-mediated but is of the cosuppression type. Resistance was effective against geographically distinct RTSV isolates. In addition, RTSV-resistant transgenic rice plants were unable to assist transmission of RTBV. Such transgenic plants could be used in an epidemiological approach to combat the spread of the tungro disease.
摘要 水稻矮缩病是由水稻矮缩病毒（RTBV）引起的，该病毒导致了病症，而水稻曲叶病毒（RTSV）则通过叶蝉协助两种病毒的传播。转基因为感病的粳稻植株（Oryza sativa）中，RTSV 复制酶（Rep）基因以正义或反义方向被导入。超过 70%的植株中含有 1 到 5 个拷贝的 Rep 基因，大多数情况下整合发生在单一的基因座上。反义序列的植株表现出对 RTSV 的显著但中等抗性（60%）；反义 RNA 的积累量很大，表明这种保护不是依赖同源性的类型。以正义方向表达全长 Rep 基因以及截短 Rep 基因的植株对 RTSV 100%抗性，即使在高接种量的挑战下也是如此。病毒 RNA 的积累量很低，这使我们得出结论，RTSV Rep 介导的抗性不是由蛋白质介导的，而是属于共抑制类型。这种抗性对地理上不同的 RTSV 分离株有效。此外，抗 RTSV 的转基因水稻植株无法协助 RTBV 的传播。这种转基因植物可以在流行病学方法中用于控制矮缩病的传播。
