Bartholomew D M, Bartley G E, Scolnik P A
Du Pont Central Research and Development, Plant Genetics Group, Wilmington, Delaware 19880-0402.
Plant Physiol. 1991 May;96(1):291-6. doi: 10.1104/pp.96.1.291.
Leaves of tomato (Lycopersicon esculentum) plants grown in soil in which moisture was lowered from field capacity to levels approaching permanent wilting point show a 10-fold increase in abscisic acid (ABA) and a 60 to 70 percent decrease in rbcS and cab steady-state mRNA levels. As indicated by transcription run-on experiments, the effect occurs primarily at the transcriptional level. Similar water deficit had only a minor effect on ABA level and on rbcS and cab expression in leaves of sitiens, an ABA mutant of tomato. Expression of rbcL, the chloroplast gene coding for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase, is not affected by water stress. Application of exogenous ABA results in decreased rbcS and cab expression in both wild-type and sitiens leaves. Analysis of the expression of individual members of the rbcS gene family indicates that under water-deficit conditions, expression derives primarily from only three of the five rbcS genes. Effects of dark adaptation and water deficit are additive for cab but not for rbcS expression. These results support the hypothesis that, at least under water-deficit conditions, ABA or a derivative thereof mediates a negative regulation of rbcS and cab transcription in tomato plants.
种植在土壤中的番茄（Lycopersicon esculentum）植株，其土壤湿度从田间持水量降低至接近永久萎蔫点时，脱落酸（ABA）含量增加10倍，而rbcS和cab稳态mRNA水平降低60%至70%。转录延伸实验表明，这种效应主要发生在转录水平。类似的水分亏缺对番茄ABA突变体sitiens叶片的ABA水平以及rbcS和cab表达仅有轻微影响。编码1,5 - 二磷酸核酮糖羧化酶/加氧酶大亚基的叶绿体基因rbcL的表达不受水分胁迫影响。外源ABA处理导致野生型和sitiens叶片中rbcS和cab表达均降低。对rbcS基因家族单个成员表达的分析表明，在水分亏缺条件下，表达主要仅来自五个rbcS基因中的三个。暗适应和水分亏缺对cab表达的影响具有叠加性，但对rbcS表达则不然。这些结果支持了这样的假说，即至少在水分亏缺条件下，ABA或其衍生物介导了番茄植株中rbcS和cab转录的负调控。
