Haake Volker, Cook Daniel, Riechmann José Luis, Pineda Omaira, Thomashow Michael F, Zhang James Z
Mendel Biotechnology, 21375 Cabot Boulevard, Hayward, CA 94545, USA.
Plant Physiol. 2002 Oct;130(2):639-48. doi: 10.1104/pp.006478.
In plants, low temperature and dehydration activate a set of genes containing C-repeat/dehydration-responsive elements in their promoter. It has been shown previously that the Arabidopsis CBF/DREB1 transcription activators are critical regulators of gene expression in the signal transduction of cold acclimation. Here, we report the isolation of an apparent homolog of the CBF/DREB1 proteins (CBF4) that plays the equivalent role during drought adaptation. In contrast to the three already identified CBF/DREB1 homologs, which are induced under cold stress, CBF4 gene expression is up-regulated by drought stress, but not by low temperature. Overexpression of CBF4 in transgenic Arabidopsis plants results in the activation of C-repeat/dehydration-responsive element containing downstream genes that are involved in cold acclimation and drought adaptation. As a result, the transgenic plants are more tolerant to freezing and drought stress. Because of the physiological similarity between freezing and drought stress, and the sequence and structural similarity of the CBF/DREB1 and the CBF4 proteins, we propose that the plant's response to cold and drought evolved from a common CBF-like transcription factor, first through gene duplication and then through promoter evolution.
在植物中，低温和脱水会激活一组在其启动子中含有C重复/脱水响应元件的基因。先前的研究表明，拟南芥CBF/DREB1转录激活因子是冷驯化信号转导中基因表达的关键调节因子。在此，我们报告了一种CBF/DREB1蛋白（CBF4）明显同源物的分离，它在干旱适应过程中发挥着同等作用。与已鉴定的三种在冷胁迫下被诱导的CBF/DREB1同源物不同，CBF4基因表达受干旱胁迫上调，但不受低温影响。在转基因拟南芥植株中过表达CBF4会导致含有C重复/脱水响应元件的下游基因被激活，这些基因参与冷驯化和干旱适应。结果，转基因植株对冷冻和干旱胁迫更具耐受性。由于冷冻和干旱胁迫之间的生理相似性，以及CBF/DREB1和CBF4蛋白的序列和结构相似性，我们提出植物对寒冷和干旱的响应是从一个共同的类CBF转录因子进化而来的，首先通过基因复制，然后通过启动子进化。
