Donson J, Kearney C M, Hilf M E, Dawson W O
Department of Plant Pathology, University of California, Riverside 92521.
Proc Natl Acad Sci U S A. 1991 Aug 15;88(16):7204-8. doi: 10.1073/pnas.88.16.7204.
Tobacco mosaic virus (TMV) produces large quantities of RNA and protein on infection of plant cells. This and other features, attributable to its autonomous replication, make TMV an attractive candidate for expression of foreign sequences in plants. However, previous attempts to construct expression vectors based on plant RNA viruses, such as TMV, have been unsuccessful in obtaining systemic and stable movement of foreign genes to uninoculated leaves in whole plants. A hybrid viral RNA (TB2) was constructed, containing sequences from two tobamoviruses (TMV-U1 and odontoglossum ringspot virus). Two bacterial sequences inserted independently into TB2 moved systemically in Nicotiana benthamiana, although they differed in their stability on serial passage. Systemic expression of the bacterial protein neomycin phosphotransferase was demonstrated. Hybrid RNAs containing both TMV-U1 and the inserted bacterial gene sequences were encapsidated by the odontoglossum ringspot virus coat protein, facilitating their transmission and amplification on passaging to subsequent plants. The vector TB2 provides a rapid means of expressing genes and gene variants in plants.
烟草花叶病毒（TMV）在感染植物细胞时会产生大量的RNA和蛋白质。由于其自主复制特性，这一特点以及其他特性使得TMV成为在植物中表达外源序列的一个有吸引力的候选对象。然而，此前基于植物RNA病毒（如TMV）构建表达载体的尝试，在使外源基因在整株植物中向未接种的叶片进行系统性和稳定移动方面均未成功。构建了一种杂交病毒RNA（TB2），其包含来自两种烟草花叶病毒（TMV-U1和齿舌兰环斑病毒）的序列。独立插入TB2的两个细菌序列在本氏烟草中能够系统性移动，尽管它们在连续传代时的稳定性有所不同。已证实细菌蛋白新霉素磷酸转移酶的系统性表达。含有TMV-U1和插入的细菌基因序列的杂交RNA被齿舌兰环斑病毒外壳蛋白包裹，便于其在传递到后续植物时进行传播和扩增。载体TB2为在植物中表达基因和基因变体提供了一种快速方法。
