Camacho Henriquez A, Sänger H L
Arch Virol. 1984;81(3-4):263-84. doi: 10.1007/BF01309998.
The acid-extractable leaf proteins of potato spindle tuber viroid (PSTV) infected tomato plants were analysed electrophoretically on polyacrylamide gels. The most prominent alteration found during disease development was the appearance of a "pathogenesis-related" protein with an apparent molecular weight of 14,000 (called P14) which is drastically increased in concentration. Its induction, however, is not viroid-specific because it is also accumulating after viral and fungal infections. The degree of P14 accumulation could be directly correlated with the severity of the disease symptoms and its concentration was found to be highest in leaves of the tomato cultivar "Rutgers" four weeks after infection. P14 was isolated from such leaf material by acid-extraction of the leaf proteins, which were concentrated from the clarified homogenates by ultrafiltration through hollow fiber systems or by precipitation at 60 per cent ammonium sulphate saturation. P14 was finally purified by ion exchange chromatography on sulfopropyl (SP-C25) Sephadex and on DEAE cellulose. A protein with properties similar to those of P14 could also be isolated from healthy tomato leaves, where its concentration is about forty to fifty times lower than PSTV-infected tissue. P14 can be stained with Coomassie Brilliant Blue, silver and ethidium bromide, it is sensitive to digestion with pronase and not altered when treated with RNase and DNase. P14 is a basic protein with an estimated isoelectric point of 10.7 and its unusual behaviour during ultrafiltration indicates that it represents an elongated rather than a globular molecule in solution. P14 seems to be different from any of the so-called "pathogenesis-related" proteins described so far in Gynura aurantiaca, "Etrog" citron, potato and tomato after viroid-infection and in tobacco, cucumber and bean leaves after virus- or fungus-induced hypersensitive reactions.
对感染马铃薯纺锤块茎类病毒（PSTV）的番茄植株的酸可提取叶片蛋白进行聚丙烯酰胺凝胶电泳分析。在病害发展过程中发现的最显著变化是出现了一种“病程相关”蛋白，其表观分子量为14000（称为P14），其浓度急剧增加。然而，它的诱导并非类病毒特异性的，因为在病毒和真菌感染后它也会积累。P14的积累程度与病害症状的严重程度直接相关，并且发现在感染四周后番茄品种“罗格斯”的叶片中其浓度最高。通过对叶片蛋白进行酸提取从这种叶片材料中分离出P14，这些蛋白通过中空纤维系统超滤或在60%硫酸铵饱和度下沉淀从澄清的匀浆中浓缩。P14最终通过在磺丙基（SP-C25）葡聚糖凝胶和二乙氨基乙基纤维素上的离子交换色谱法纯化。也可以从健康番茄叶片中分离出一种性质与P14相似的蛋白，其浓度比感染PSTV的组织低约四十到五十倍。P14可用考马斯亮蓝、银和溴化乙锭染色，它对链霉蛋白酶消化敏感，用核糖核酸酶和脱氧核糖核酸酶处理时不变。P14是一种碱性蛋白，估计等电点为10.7，其在超滤过程中的异常行为表明它在溶液中代表一种细长而非球形的分子。P14似乎不同于迄今为止在类病毒感染后的紫背天葵、“埃特罗格”香橼、马铃薯和番茄以及病毒或真菌诱导的过敏反应后的烟草、黄瓜和菜豆叶片中描述的任何一种所谓的“病程相关”蛋白。
