低温会对植物造成伤害，甚至死亡。林木由于生长周期较长，更容易遭受低温灾害。植物主要通过冷驯化来提高抗低温的能力，因此研究植物冷驯化的分子机理是通过生物工程手段提高植物耐低温能力的前提和基础。以白桦为材料，申请者发现转录因子BpERF98在整个冷驯化过程中平均上调表达79倍，为上调倍数最高的转录因子。并且BpERF98与152个参与白桦冷驯化的基因（CORs）协同表达。进一步研究发现，过量表达BpERF98能提高白桦的抗低温能力。基于以上基础，本项目拟开展如下内容：获得BpERF98抑制表达的转基因白桦，并检测其耐低温能力；验证BpCBFs对BpERF98的调控关系；明确BpERF98对COR基因的调控关系；构建BpERF98的基因调控网络，揭示其调控机理。本项目的研究将进一步完善林木及植物的冷驯化分子机理，为林木抗低温分子育种提供理论基础及候选基因。

Low temperature causes damage to plants and even death. Trees are more prone to suffer disasters of low temperature due to the longer growth cycle. Most temperate plants can acquire tolerance to freezing temperatures by means of a prior exposure to low nonfreezing temperatures, a process known as cold acclimation. Studying the molecular mechanism of plant cold acclimation is the prerequisite and basis for improving plant's ability to resist low temperature via bioengineering. In the previous study, we found the average expression of BpERF98 was up-regulated 79 times in the whole cold acclimation process, which was the most up-regulated transcription factor. In addition, BpERF98 co-expressed with 152 COR genes of birch. Further study showed that overexpression of BpERF98 increased the low temperature resistance of Betula platyphylla. Based on the above basis, this project will carry out the following research, investigation of low temperature resistance of BpERF98 repressed transgenic birch; defining the regulation between BpCBFs and BpERF98; revealing the regulation between BpERF98 and COR genes; construction of gene regulatory network of BpERF98. Our study will further improve the molecular mechanism of cold acclimation of trees and plants, and provide a theoretical basis and candidate genes for low temperature molecular breeding of trees.