低温弱光是喜温园艺作物生产中的主要逆境。项目在发现番茄等低温驯化和油菜素内酯BRs通过激发质膜活性氧ROS产生抗逆反应的基础上，以代表性园艺作物番茄中不同突变体、不同温敏性基因型和基因沉默或过表达植株为材料，以番茄生产中经常遭遇的低温弱光逆境为重点，研究其响应中BRs信号和ROS产生变化；明确BRs、光和氧化还原redox信号同低温抗性及其同CBF的关系，探明ROS作为第二信使在BRs诱导抗逆反应信号途径中的作用；利用转录组分析、正向和反向遗传学思路，鉴定相关基因功能，明确BRs及其次生redox信号如何通过活化光合作用中redox敏感蛋白提高光合效率和温度适应性的信号转导途径、关键节点及其作用机理。研究可望加深BRs和ROS互作诱导作物对低温弱光抗性分子机制的理解，为建立一条基于BRs、光环境和ROS信号互作提高蔬菜低温弱光抗性和光合效率的新途径奠定理论基础，具有重要的科学与现实意义。

Chilling at low light is a major stress for most temperate horticultural crops. We have found that reactive oxygen species (ROS) produced by NADPH oxidase are mediators of stress tolerance in cucumber or tomato response to chilling stress and brassinosteroids (BRs). Based on current progress, we will use a series of tomato mutants, wild accessions with different chilling sensitivity, transgenic lines and RNAi plants of specific genes to study the homeostasis of BRs and ROS in response to environment changes, with emphasis on chilling at low light, a stress frequently encountered by tomato during winter-spring transition. We will study the role of CBF regulation by BRs, light and redox signal in chilling stress tolerance and dissect the role of ROS as second messengers in BR-induced stress response. Through transcriptomic analysis and forward and reverse genetic studies, we will identify genes potentially involved in BR-induced chilling stress tolerance and study the functions of the genes, and finally dissect the signaling pathway, critical components and mechanisms of BR and its second redox signals for their role in photosynthesis through activating the redox sensitive enzymes in photosynthetic apparatus and in the adaptation of chill stress. The study will deepen the understanding of the molecular mechanisms of interplay between BRs and ROS in the regulation of tolerance and adaptation to temperature stresses. The research of the project will found theoretic bases for establishing a novel technology to regulate the vegetable tolerance to low temperature at low light based on interplay of BRs, light and ROS, and therefore is of fundamental significance for horticultural science and industry.