National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
Transgenic Res. 2011 Jun;20(3):569-81. doi: 10.1007/s11248-010-9440-3. Epub 2010 Sep 14.
Expression of artificial microRNAs (amiRNAs) in plants can target and degrade the invading viral RNA, consequently conferring virus resistance. Two amiRNAs, targeting the coding sequence shared by the 2a and 2b genes and the highly conserved 3' untranslated region (UTR) of Cucumber mosaic virus (CMV), respectively, were generated and introduced into the susceptible tomato. The transgenic tomato plants expressing amiRNAs displayed effective resistance to CMV infection and CMV mixed with non-targeted viruses, including tobacco mosaic virus and tomato yellow leaf curl virus. A series of grafting assays indicate scions originated from the transgenic tomato plant maintain stable resistance to CMV infection after grafted onto a CMV-infected rootstock. However, the grafting assay also suggests that the amiRNA-mediated resistance acts in a cell-autonomous manner and the amiRNA signal cannot be transmitted over long distances through the vascular system. Moreover, transgenic plants expressing amiRNA targeting the 2a and 2b viral genes displayed slightly more effective to repress CMV RNA accumulation than transgenic plants expressing amiRNA targeting the 3' UTR of viral genome did. Our work provides new evidence of the use of amiRNAs as an effective approach to engineer viral resistance in the tomato and possibly in other crops.
人工 microRNAs (amiRNAs) 在植物中的表达可以靶向并降解入侵的病毒 RNA，从而赋予植物抗病毒能力。针对黄瓜花叶病毒 (CMV) 的 2a 和 2b 基因编码区以及高度保守的 3'非翻译区 (UTR)，分别生成了两种 amiRNA，并将其导入易感番茄中。表达 amiRNA 的转基因番茄植株对 CMV 感染以及 CMV 与非靶向病毒（包括烟草花叶病毒和番茄黄曲叶病毒）的混合感染表现出有效的抗性。一系列嫁接实验表明，源自转基因番茄植株的接穗在嫁接到 CMV 感染的砧木上后，仍能保持对 CMV 感染的稳定抗性。然而，嫁接实验还表明，amiRNA 介导的抗性以细胞自主的方式发挥作用，amiRNA 信号不能通过维管束系统远距离传递。此外，靶向病毒 2a 和 2b 基因的 amiRNA 表达的转基因植物比靶向病毒基因组 3'UTR 的 amiRNA 表达的转基因植物更有效地抑制 CMV RNA 积累。我们的工作为利用 amiRNAs 作为一种有效手段来工程番茄和可能其他作物的抗病毒能力提供了新的证据。
