Molecular genetical analysis of plant gene expression by phytohormones.

干旱、低温和盐胁迫等环境胁迫会引发植物激素脱落酸（阿坝）的产生，进而诱导各种基因的表达。阿坝在子座关闭、种子成熟和休眠中起作用。许多ABA诱导基因也在种子发育的胚胎发生后期表达，为了从分子水平了解植物对干旱胁迫的反应，我们克隆了水分胁迫诱导的基因，并以拟南芥为材料分析了它们的表达。我们利用差异杂交技术分离了9个水分胁迫诱导的cDNA，命名为RD（RD for Responsive to Desication）。这些RD基因的mRNA诱导时间不同。脱落酸诱导的mRNA对应于命名为RD22、RD29、RD17和RD20的克隆，但不对应于命名为RD19、RD21、RD28、RD2和RD26的克隆，这表明存在从水分胁迫到RD基因表达的若干信号转导途径。RD22与一种未鉴定的蚕豆种子蛋白具有局部同源性。RD17显示与RAB蛋白的序列同源性。水分胁迫对RD29基因有两步诱导作用。第一次快速诱导发生在20 min，第二次缓慢诱导发生在3h。阿坝参与RD29基因的第二次缓慢表达。RD29的两个基因rd29A和rd29B串联定位在A.拟南芥基因组转rd29A启动子驱动的GUS报告基因在干旱胁迫、盐胁迫、低温胁迫和阿坝处理下均被诱导表达。还有烟草。

Environmental stresses, such as drought, low temperature and salt stresses, trigger the production of plant hormone abscisic acid(ABA), which in turn induces various genes. ABA functions in stromatal closure, seed maturation and dormancy. Many ABAinducible genes are also expressed at the late stage of embryogenesis during seed development.In order to understand plant responses to desiccation stress at molecular level, we cloned genes that are induced by water-deficit stress and to analyze their expression using Arabidopsis thaliana. We isolated nine cDNAs induced by the effects of water deficit by using the technique of differential hybridization and named them RD(RD for Responsive to Desic ation). The timing of induction of their mRNAs varies between these RD genes. Abscisic acid induces mRNAs that correspond to clones designated RD22, RD29, RD17 and RD20 but not to those designated RD19, RD21, RD28, RD2 and RD26, indicating that there are several signal-transduction pathways from water stress to expression of RD genes. RD22 exhibits local homology to an unidentified seed protein of Vicia faba. RD17 shows sequence homology to RAB proteins. Two step induction of RD29 gene by water deficiency was observed. The first quick induction occured in 20 min and the second slow induction was observed in 3h. ABA is involved in the second slow expression of the RD29 gene. Two genes for RD29, rd29A and rd29B, are tandemly located in 8 kbp region on A. thaliana genome. The GUS reporter gene driven by the rd29A promoter was significantly induced not only by desiccation stress but also by salt and cold stresses or ABA treatment in both transgenic A. thaliana and tobacco.