Department of Botany and Plant Sciences, University of California, 92521, Riverside, CA, USA.
Planta. 1990 Aug;182(1):27-33. doi: 10.1007/BF00239979.
The accumulation of abscisic acid (ABA) has been shown to regulate some of the changes in gene expression which occur during water deficit. In order to characterize these ABA-induced changes, we have identified and isolated three copy DNAs (cDNAs) that represent genes which are expressed in response to ABA during drought stress. The ABA-deficient mutant of tomato, flacca, synthesizes low levels of ABA during water deficit compared to the wild type (WT) (Lycopersicon esculentum Mill. cv. Ailsa Craig). The mutant flacca was used to distinguish cDNAs corresponding to mRNAs which accumulate during water deficit in response to elevated levels of ABA from those mRNAs which are not ABA responsive. A cDNA library representing the mRNA population of wilted WT tomato leaves was constructed and a series of differential screens was used to select cDNAs that represent putative ABA- and drought-induced mRNAs. Three cDNAs were isolated from the screens and were identified as pLE4, pLE16, and pLE25. The corresponding mRNAs were preferentially expressed in wilted WT leaves and were not exessed in wilted ABA-deficient mutant leaves. The inability of the mutant to accumulate these drought-induced transcripts was reversed with exogenously applied ABA. A correlation was observed between the accumulation of the drought-induced mRNAs and the endogenous ABA levels measured in WT leaves throughout increasing periods of water deficit. These results indicate that endogenous ABA regulates the accumulation of pLE4, pLE16, and pLE25 mRNAs in tomato leaves during water deficit.
脱落酸（ABA）的积累已被证明可以调节水分亏缺过程中发生的一些基因表达变化。为了描述这些 ABA 诱导的变化，我们已经鉴定并分离了三个代表在干旱胁迫期间响应 ABA 表达的基因的 cDNA。与野生型（WT）相比，番茄的 ABA 缺陷突变体 flacca 在水分亏缺期间合成的 ABA 水平较低（番茄 Lycopersicon esculentum Mill. cv. Ailsa Craig）。突变体 flacca 用于区分对应于在水分亏缺期间由于 ABA 水平升高而积累的 mRNA 的 cDNA 与那些不响应 ABA 的 mRNA。构建了代表萎蔫 WT 番茄叶片 mRNA 群体的 cDNA 文库，并进行了一系列差异筛选，以选择代表潜在的 ABA 和干旱诱导的 mRNA 的 cDNA。从筛选中分离出三个 cDNA，并鉴定为 pLE4、pLE16 和 pLE25。相应的 mRNA 优先在萎蔫 WT 叶片中表达，而不在萎蔫 ABA 缺陷突变体叶片中表达。突变体无法积累这些干旱诱导的转录本，这可以通过外源施加 ABA 来逆转。在 WT 叶片中，随着水分亏缺时间的延长，观察到干旱诱导的 mRNA 积累与内源 ABA 水平之间存在相关性。这些结果表明，内源 ABA 调节番茄叶片在水分亏缺期间 pLE4、pLE16 和 pLE25 mRNA 的积累。
