Cutt J R, Harpster M H, Dixon D C, Carr J P, Dunsmuir P, Klessig D F
Waksman Institute at Rutgers, State University of New Jersey, Piscataway 08855.
Virology. 1989 Nov;173(1):89-97. doi: 10.1016/0042-6822(89)90224-9.
Correlation of the temporal and spacial pattern of induction of the pathogenesis-related (PR) genes PR1a, PR1b, and PR1c with viral infections in certain tobacco cultivars has implicated PR proteins in viral disease resistance. To test whether the PR1 proteins of tobacco are involved in viral resistance, transgenic Nicotiana tabacum plants were constructed which constitutively express the PR1b gene. This protein was secreted from cells of transgenic plants and accumulated in the extracellular space at levels equivalent to those found in nontransgenic plants in association with disease resistance. Transgenic plants derived from the cultivar (cv.) Xanthi (susceptible to tobacco mosaic virus [TMV] infection) exhibited no delayed onset or reduction in the severity of systemic symptoms after TMV infection. In transgenic plants derived from cv. Xanthi-nc (TMV resistant), the time of appearance, the size and general morphology, and the number of viral lesions produced were similar to the parental control plants after TMV infection. These data indicate that the PR1b protein of tobacco is not sufficient for TMV resistance, and imply that the PR1 proteins may not function as unique antiviral factors.
病程相关（PR）基因PR1a、PR1b和PR1c诱导的时空模式与某些烟草品种中的病毒感染之间的相关性表明，PR蛋白与病毒病抗性有关。为了测试烟草的PR1蛋白是否参与病毒抗性，构建了组成型表达PR1b基因的转基因烟草植株。这种蛋白从转基因植物细胞中分泌出来，并在细胞外空间积累，其水平与在具有抗病性的非转基因植物中发现的水平相当。来自品种（cv.）黄花烟（易受烟草花叶病毒[TMV]感染）的转基因植物在TMV感染后，全身症状的发作没有延迟，严重程度也没有降低。在来自cv. 黄花烟-nc（抗TMV）的转基因植物中，TMV感染后，病毒损伤出现的时间、大小和总体形态以及数量与亲本对照植物相似。这些数据表明，烟草的PR1b蛋白不足以抵抗TMV，这意味着PR1蛋白可能不是唯一的抗病毒因子。
