Overexpression of the Arabidopsis CBF3 transcriptional activator mimics multiple biochemical changes associated with cold acclimation
Overexpression of the Arabidopsis CBF3 transcriptional activator mimics multiple biochemical changes associated with cold acclimation
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DOI：
10.1104/pp.124.4.1854
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发表时间：
2000-12-01
期刊：
影响因子：
7.4
通讯作者：
Thomashow, MF
中科院分区：
文献类型：
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作者：
Gilmour, SJ;Sebolt, AM;Thomashow, MF
我们进一步研究了拟南芥CBF调控基因在冷驯化中的作用，冷驯化是指某些植物在暴露于低温时抗冻性增强的过程。CBF基因在低温响应时会迅速被诱导，它编码转录激活因子，这些转录激活因子控制其启动子中含有C - 重复序列/脱水响应元件DNA调控元件的基因的表达。在转基因拟南芥植株中，CBF1或CBF3（分别也称为DREB1b和DREB1a）的组成型表达已被证明可诱导目标COR（冷调节）基因的表达，并增强未驯化植株的抗冻性。在此我们证明，在拟南芥中过表达CBF3也会增加冷驯化植株的抗冻性。此外，我们表明它导致了与冷驯化相关的多种生化变化：表达CBF3的植株脯氨酸（Pro）和总可溶性糖（包括蔗糖、棉子糖、葡萄糖和果糖）水平升高。过表达CBF3的植株P5CS转录本水平也升高，这表明脯氨酸水平的升高至少部分是由于关键的脯氨酸生物合成酶Δ(1)-吡咯啉 - 5 - 羧酸合成酶的表达增加所致。这些结果使我们提出，CBF3整合了冷驯化反应多个组分的激活。
We further investigated the role of the Arabidopsis CBF regulatory genes in cold acclimation, the process whereby certain plants increase in freezing tolerance upon exposure to low temperature. The CBF genes, which are rapidly induced in response to low temperature, encode transcriptional activators that control the expression of genes containing the C-repeat/dehydration responsive element DNA regulatory element in their promoters. Constitutive expression of either CBF1 or CBF3 (also known as DREB1b and DREB1a, respectively) in transgenic Arabidopsis plants has been shown to induce the expression of target COR (cold-regulated) genes and to enhance freezing tolerance in nonacclimated plants. Here we demonstrate that overexpression of CBF3 in Arabidopsis also increases the freezing tolerance of cold-acclimated plants. Moreover, we show that it results in multiple biochemical changes associated with cold acclimation: CBF3-expressing plants had elevated levels of proline (Pro) and total soluble sugars, including sucrose, raffinose, glucose, and fructose. Plants overexpressing CBF3 also had elevated P5CS transcript levels suggesting that the increase in Pro levels resulted, at least in part, from increased expression of the key Pro biosynthetic enzyme Delta (1)-pyrroline-5-carboxylate synthase. These results lead us to propose that CBF3 integrates the activation of multiple components of the cold acclimation response.