Batuman Ozgur, Mawassi Munir, Bar-Joseph Moshe
The S. Tolkowsky laboratory, The Virology Department, ARO, The Volcani Center, Bet Dagan, 50250, Israel.
Virus Genes. 2006 Dec;33(3):319-27. doi: 10.1007/s11262-006-0071-y.
In an attempt to utilize post-transcriptional gene silencing (PTGS) as a means to impart resistance against Citrus tristeza virus (CTV) into citrus plants, the p23 + 3'UTR sequence (p23U) of the VT strain of CTV was engineered to fold into a double-stranded (ds) RNA structure. The resulting construct (p23UI) was introduced into Nicotiana benthamiana and Alemow (Citrus macrophylla) plants by Agrobacterium-mediated transformation. Transgenic p23UI- N. benthamiana were resistant to infection with a viral vector made of Grapevine virus A (GVA) + p23U (GVA-p23U), as indicated by the absence of the chimeric virus from inoculated plants. Inoculation of transgenic p23UI Alemow plants with CTV resulted in delayed appearance of symptoms in 9 out of the 70 transgenic plants. However, none of the plants showed durable resistance, as indicated by the obtaining of similar Northern hybridization signals from both transgenic and non-transgenic citrus plants. The possible causes for the failure of transgenic citrus plants to confer durable resistance to CTV are discussed.
为了利用转录后基因沉默（PTGS）将抗柑橘衰退病毒（CTV）的能力导入柑橘植株，将CTV VT株系的p23 + 3'UTR序列（p23U）设计成能折叠成双链（ds）RNA结构。通过农杆菌介导的转化，将所得构建体（p23UI）导入本氏烟草和粗柠檬（Citrus macrophylla）植株。转基因p23UI-本氏烟草对由葡萄病毒A（GVA）+ p23U（GVA-p23U）组成的病毒载体感染具有抗性，接种植株中不存在嵌合病毒表明了这一点。用CTV接种转基因p23UI粗柠檬植株后，70株转基因植株中有9株症状出现延迟。然而，从转基因和非转基因柑橘植株获得的Northern杂交信号相似，表明没有一株植株表现出持久抗性。文中讨论了转基因柑橘植株未能赋予对CTV持久抗性的可能原因。
