Inhibition of long-distance movement of RNA silencing signals in Nicotiana benthamiana by Apple chlorotic leaf spot virus

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• 作者：Hajime Yaegashi ; Akihiro Tamura ; Masamichi Isogai ; Nobuyuki Yoshikawa
• 关键词：ACLSV ; RNA silencing suppressor ; Movement protein ; Systemic silencing ; Silencing signal ; Long-distance movement
• 刊名：Virology
• 出版年：2008
• 出版时间：20 December 2008
• 年：2008
• 卷：382
• 期：2
• 页码：199-206
• 全文大小：994 K

文摘

Apple chlorotic leaf spot virus 50 kDa movement protein (P50) acts as a suppressor of systemic silencing in Nicotiana benthamiana. Here, we investigate the mode of action of P50 suppressor. An agroinfiltration assay in GFP-expressing N. benthamiana line16c (GFP-plant) showed that P50 could not prevent the short-distance spread of silencing. In grafting experiments, the systemic silencing was inhibited in GFP-plants (scion) grafted on P50-expressing N. benthamiana (P50-plant; rootstock) when GFP silencing was induced in rootstock. In double-grafted plants, GFP-plant (scion)/P50-plant (interstock)/GFP-plant (rootstock), the systemic silencing in scion was inhibited when GFP silencing was induced in rootstock. Analysis of P50 deletion mutants indicated that the N-terminal region (amino acids 1–284) is important for its suppressor activity. In gel mobility shift assay, P50 lacks binding ability with siRNAs. These results indicated that P50 has a unique suppressor activity that specifically inhibits the long-distance movement of silencing signals.