On the role of RNA silencing in the pathogenicity and evolution of viroids and viral satellites.
نویسندگان
چکیده
Viroids and most viral satellites have small, noncoding, and highly structured RNA genomes. How they cause disease symptoms without encoding proteins and why they have characteristic secondary structures are two longstanding questions. Recent studies have shown that both viroids and satellites are capable of inducing RNA silencing, suggesting a possible role of this mechanism in the pathology and evolution of these subviral RNAs. Here we show that preventing RNA silencing in tobacco, using a silencing suppressor, greatly reduces the symptoms caused by the Y satellite of cucumber mosaic virus. Furthermore, tomato plants expressing hairpin RNA, derived from potato spindle tuber viroid, developed symptoms similar to those of potato spindle tuber viroid infection. These results provide evidence suggesting that viroids and satellites cause disease symptoms by directing RNA silencing against physiologically important host genes. We also show that viroid and satellite RNAs are significantly resistant to RNA silencing-mediated degradation, suggesting that RNA silencing is an important selection pressure shaping the evolution of the secondary structures of these pathogens.
منابع مشابه
ogenicity, viroid evolution, Citrus exocortis viroid, Potato spindle tuber viroid, Peach latent mosaic viroid, Chrysan- themum chlorotic mottle viroid
Viroids are autonomously replicating, small singlestranded circular RNA molecules that do not code for proteins and may cause disease in infected, susceptible plants. Viroids have the ability to induce both RNA-mediated transcriptional gene silencing (TGS) and posttranscriptional gene silencing (PTGS) in infected plants. Viroid PTGS has also been demonstrated in a wheat germ extract system. A p...
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ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 101 9 شماره
صفحات -
تاریخ انتشار 2004