Low Temperature Regulatory Circuits and Gene Regulons in Higher Plants

植物对低温的反应差别很大。一个极端是来自热带和亚热带地区的植物，如大豆和水稻，当暴露在0至12摄氏度的低温下时会受到伤害。与此形成鲜明对比的是，来自温带地区的植物不仅耐冷，而且许多植物，如拟南芥和小麦，在暴露于低的非冻结温度后可以在冻结中存活，这种现象被称为“冷驯化”。该项目的总体目标是了解耐寒性的“基因组”基础。具体的重点将是更详细地了解植物如何在改变基因表达方面对低温作出反应。这一重点的动机是最近在拟南芥中证明，冷驯化涉及冷调节基因的行动，包括CBF调节子，一组基因，赋予冷冻耐受性和协调调节的CBF转录激活因子。该项目将包括三个相关的调查领域。首先，将构建一个低温“接线图”，其中包括低温调节电路和它们控制的基因调节子的定义。研究的第二条线将是确定在不同的耐冷冻性的植物中低温调节基因的相似性和差异性。研究的第三条线将是确定拟南芥CBF冷反应途径是否在其他植物中高度保守，以及植物耐寒性的差异是否可以追溯到CBF冷反应途径的差异。比较和功能基因组学方法将用于解决这些问题，包括使用DNA微阵列的基因表达谱。总之，这些调查路线将提供更深入的了解“基因组机制”，植物已经进化到科普低温，并有可能提供“遗传工具”，以提高植物的耐冷性，具有相当大的农艺和经济重要性的性状。由于CBF调节子不仅赋予植物抗冻性，还赋予其脱水耐受性，因此该项目的结果也有可能提供遗传工具，以提高农业上重要植物的耐旱性和耐盐性。http://aztec.stanford.edu/cold

Plants vary greatly in their responses to cold temperatures. At one extreme are plants from tropical and subtropical regions such as soybean and rice, which suffer injury when exposed to chilling temperatures between 0 and 12 degrees Celcius. In sharp contrast, plants from temperate regions are not only chilling tolerant, but many, such as Arabidopsis and wheat, can survive freezing after exposure to low nonfreezing temperatures, a phenomenon known as "cold acclimation." The overall goal of this project is to understand the "genomic" basis of cold tolerance. The specific focus will be to develop a more detailed understanding of how plants respond to low temperature in terms of altering gene expression. This emphasis is motivated by the recent demonstration in Arabidopsis that cold acclimation involves the action of cold-regulated genes including the CBF regulon, a group of genes that imparts freezing tolerance and is coordinately regulated by the CBF transcriptional activators. This project will comprise three related lines of investigation. In the first, a low temperature "wiring diagram" will be constructed that includes a definition of low temperature regulatory circuits and the gene regulons that they control. The second line of investigation will be to determine the similarities and differences of low temperature-regulated genes in plants that differ in freezing tolerance. The third line of investigation will be to determine whether the Arabidopsis CBF cold-response pathway is highly conserved in other plants and whether differences in plant cold tolerance can be traced to differences in CBF cold-response pathways. Comparative and functional genomics approaches will be used to address these issues including gene expression profiling using DNA microarrays. In sum, these lines of investigation will provide a deeper understanding of the "genomic mechanisms" that plants have evolved to cope with low temperature and have the potential to provide "genetic tools" to improve the cold tolerance of plants, traits of considerable agronomic and economic importance. In as much as the CBF regulon not only imparts freezing tolerance, but dehydration tolerance as well, the results of this project also have the potential to provide genetic tools to improve the drought and salinity tolerance of agriculturally important plants.Deliverables:Microarray data and other information about the project can be found at: http://aztec.stanford.edu/cold.