Lawton M A, Dixon R A, Hahlbrock K, Lamb C J
Eur J Biochem. 1983 Jan 17;130(1):131-9.
Changes in the activity levels of mRNAs encoding phenylalanine ammonia-lyase and chalcone synthase, two characteristic enzymes of phenylpropanoid biosynthesis, in elicitor-treated cells of dwarf French bean (Phaseolus vulgaris L.) have been investigated by immunoprecipitation of [35S]methionine-labelled enzyme subunits synthesised in vitro in an mRNA-dependent rabbit reticulocyte lysate translation system. Elicitor heat-released from cell walls of Colletotrichum lindemuthianum, the causal agent of anthracnose disease of bean, causes marked rapid increases in the polysomal activities of the mRNAs encoding the two enzymes concomitant with the phase of rapid increase in enzyme activity at the onset of phaseollin accumulation during the phytoalexin defence response. Increased polysomal mRNA activities encoding the two enzymes can be observed 30 min after elicitor treatment. The patterns of induction of the mRNA activities are broadly similar with respect to time and elicitor concentration although small but distinct differences between the enzymes were observed in the elicitor concentration giving maximum induction. There is a close correlation between the induction of polysomal mRNA activity and the induction of enzyme synthesis in vivo by elicitor treatment with respect to both the kinetics of induction and the dependence on elicitor concentration. The data indicate that elicitor stimulation of phenylalanine ammonia-lyase and chalcone synthase synthesis in vivo is largely a result of increased polysomal activity of the mRNAs encoding these enzymes. Similar patterns of induction of polysomal mRNA activity are observed with elicitor preparations from a variety of sources. The marked increases in polysomal mRNA activities encoding phenylalanine ammonia-lyase and chalcone synthase are increases as a proportion of total cellular mRNA activity, indicating that elicitor does not increase these polysomal mRNA activities by stimulation of selective recruitment from the total pool of cellular mRNA.
通过在依赖mRNA的兔网织红细胞裂解物翻译系统中体外合成的[35S]甲硫氨酸标记的酶亚基的免疫沉淀，研究了矮生菜豆（Phaseolus vulgaris L.）激发子处理细胞中编码苯丙氨酸解氨酶和查尔酮合酶（苯丙烷生物合成的两种特征酶）的mRNA活性水平的变化。从菜豆炭疽病病原体菜豆炭疽菌细胞壁热释放的激发子，在植物抗毒素防御反应中，在菜豆素积累开始时酶活性快速增加阶段，导致编码这两种酶的mRNA的多核糖体活性显著快速增加。激发子处理30分钟后可观察到编码这两种酶的多核糖体mRNA活性增加。尽管在最大诱导的激发子浓度方面观察到两种酶之间存在微小但明显的差异，但mRNA活性的诱导模式在时间和激发子浓度方面大致相似。就诱导动力学和对激发子浓度的依赖性而言，多核糖体mRNA活性的诱导与激发子处理在体内诱导酶合成之间存在密切相关性。数据表明，激发子在体内刺激苯丙氨酸解氨酶和查尔酮合酶的合成主要是由于编码这些酶的mRNA的多核糖体活性增加。用来自各种来源的激发子制剂观察到类似的多核糖体mRNA活性诱导模式。编码苯丙氨酸解氨酶和查尔酮合酶的多核糖体mRNA活性的显著增加是作为总细胞mRNA活性的比例增加的，这表明激发子不是通过刺激从总细胞mRNA池中选择性募集来增加这些多核糖体mRNA活性的。
