Fenczik C A, Padgett H S, Holt C A, Casper S J, Beachy R N
Division of Biology and Biomedical Sciences, Washington University, St. Louis, Missouri 63110, USA.
Mol Plant Microbe Interact. 1995 Sep-Oct;8(5):666-73. doi: 10.1094/mpmi-8-0666.
Tobacco mosaic virus (TMV) which contains the movement protein (MP) of odontoglossum ringspot tobamovirus (ORSV) in place of the TMV MP systemically infects orchids but causes local infection in tobacco unless the carboxy-terminal 48 amino acids of the MP are deleted (C. A. Holt, C. A. Fenczik, S. J. Casper, and R. N. Beachy; Virology, in press, 1995). Frameshift mutations were created within the 3' ends of the MP gene that led to truncations of the ORSV MP by 11, 19, 28, 37, and 48 amino acids; each of the mutant MP genes was inserted into the cloned cDNA of TMV in place of the TMV MP and infectious transcripts were produced. Virus containing mutant MPs were used to infect vanilla orchids, a systemic host of ORSV, and tobacco plants. Removal of 11 amino acids from the ORSV MP prevented spread of the chimeric virus in orchids while restoring the ability to cause a systemic infection on tobacco. Further deletions of the MP affected the size of virus-induced necrotic local lesions on tobacco cv. Xanthi NN and the systemic spread and accumulation of virus in cv. Xanthi nn, a systemic host of TMV. However, each virus replicated to equivalent levels in protoplasts. A mechanism by which the ORSV MP limits the spread of the chimeric virus is proposed.
烟草花叶病毒（TMV），其运动蛋白（MP）被齿舌兰环斑烟草花叶病毒（ORSV）的运动蛋白取代，能系统感染兰花，但在烟草中仅引起局部感染，除非该运动蛋白的羧基末端48个氨基酸被删除（C.A.霍尔特、C.A.芬齐克、S.J.卡斯珀和R.N.比奇；《病毒学》，即将发表，1995年）。在运动蛋白基因的3'末端产生移码突变，导致ORSV运动蛋白分别截短11、19、28、37和48个氨基酸；每个突变运动蛋白基因被插入TMV的克隆cDNA中取代TMV运动蛋白，并产生感染性转录本。含有突变运动蛋白的病毒用于感染香草兰花（ORSV的一个系统寄主）和烟草植株。从ORSV运动蛋白中去除11个氨基酸可阻止嵌合病毒在兰花中的传播，同时恢复其在烟草上引起系统感染的能力。运动蛋白的进一步缺失影响了烟草品种Xanthi NN上病毒诱导的坏死局部病斑的大小，以及病毒在TMV的系统寄主烟草品种Xanthi nn中的系统传播和积累。然而，每种病毒在原生质体中的复制水平相当。本文提出了一种ORSV运动蛋白限制嵌合病毒传播的机制。
