Sherwood J L, Fulton R W
Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 58706, USA.
Virology. 1982 May;119(1):150-8. doi: 10.1016/0042-6822(82)90072-1.
Nicotiana sylvestris infected by strains of tobacco mosaic virus (TMV) causing mosaic can be superinfected in the dark green leaf tissue, but not light green tissue, by necrotizing strains of TMV. The dark green tissue, however, is much less susceptible than healthy tissue, to some extent, even to unrelated viruses. The RNA of necrotizing strains of TMV was relatively more infectious than intact virus on mosaic than on healthy leaves and caused lesions in both light and dark green tissues. The same relationship was found in Nicotiana longiflora and, when the protecting strain in N. sylvestris could be used as a challenge, in Capsicum baccatum. The efficiency of superinfection by RNA was not found with viruses unrelated to TMV. When bentonite at 1 mg/ml, which is known to strip protein from TMV, was included in the inoculum of intact TMV it superinfected in the same manner as RNA. RNA of a necrotizing strain of TMV, encapsidated in brome mosaic virus protein and used as a challenge, superinfected in the same manner as RNA. When encapsidated in common TMV protein, however, it behaved as native virus. Cross protection apparently results from the prevention of uncoating of related challenge virus in light green tissue of N. sylvestris. Locally inoculated N. sylvestris leaves were insusceptible to challenge RNA or intact virus when the protecting virus was increasing. After increase ceased, RNA was more infectious than intact virus.
感染了引起花叶病的烟草花叶病毒（TMV）毒株的野生烟草，在深绿色叶片组织中可被TMV坏死毒株超感染，但在浅绿色组织中则不会。然而，深绿色组织在一定程度上比健康组织更不易感，甚至对无关病毒也是如此。TMV坏死毒株的RNA在感染花叶病的叶片上比在健康叶片上相对更具感染性，并且在浅绿色和深绿色组织中均会引起病斑。在长花烟草中也发现了同样的关系，并且当野生烟草中的保护毒株可作为挑战毒株时，在辣椒中也发现了这种关系。与TMV无关的病毒未发现RNA超感染的效果。当在完整TMV接种物中加入已知能从TMV上剥离蛋白质的1毫克/毫升膨润土时，它以与RNA相同的方式进行超感染。包裹在雀麦花叶病毒蛋白中并用作挑战毒株的TMV坏死毒株的RNA，以与RNA相同的方式进行超感染。然而，当包裹在普通TMV蛋白中时，它表现得如同天然病毒。交叉保护显然是由于阻止了相关挑战病毒在野生烟草浅绿色组织中的脱壳。当保护病毒在增加时，局部接种的野生烟草叶片对挑战RNA或完整病毒不敏感。增加停止后，RNA比完整病毒更具感染性。
