转录因子NF-YA在柑橘成花过程中应答环境调控FT的分子机制

果树成花的时间、数量和质量直接影响其产量、品质和效益。成花素FT基因已被证明是木本果树成花的关键基因，在木本植物中除调控开花外还调控休眠，表明其可能进化出与模式植物不同的调控方式。然而木本植物FT调控的机制迄今鲜见报道。本项目前期发现，柑橘中NF-YA不仅可结合FT启动子上调控其表达，还可响应低温和干旱，恰好与柑橘成花所需的环境要求一致，可能是一种新的、不同于模式植物FT调控方式。鉴于CO是模式植物中FT光周期正向调控因子，本项目拟采用酵母双杂、BiFC、EMSA和ChIP等蛋白-蛋白、蛋白-DNA互作研究方法比较NF-YA与CO作用异同，筛选上游调控因子和下游靶位点；进一步通过逆境处理和转基因表型及转录组分析，研究NF-YA作用与上、下游基因间网络关系，以探明NF-YA响应环境、正向调控FT的分子机理，丰富木本植物成花调控理论，为研发柑橘花芽分化调控技术和品种改良提供理论支撑和靶标参数。

The time, quantity and quality of the flowers are very important factors affecting the yield, quality and benefit of fruit trees. The florigen FT gene has been proved to be the key gene for the flowering in woody fruit plants. In addition to regulating flowering, the FT gene can also participate in regulation of dormancy indicates that it may have evolved a different regulation pathway than model plants. However, the molecular mechanism of FT gene regulation in woody plants has not been reported so far. In earlier studies, we found that NF-YA, a transcription factor in citrus plants could not only bind to the promoter of FT gene, but also respond to low temperature and drought stress, which are just the same as the environmental requirements for citrus flowering. This may hint a novel regulatory pahtway different from the current known reported in model plants. Since CONSTANS is the key regulator of FT in model plants, this project intends to use protein-protein, protein-DNA interaction research methods, such as yeast two-hybrid, BiFC, EMSA, ChIP, etc. To compare the similar or different mechanism between NF-YA and CONSTANS, and then screen upstream regulatory factors and downstream target sites in citrus plants. Stress treatment, phenotyping and transcriptome analysis of transgenic plants will be made to study the gene network connecting NF-YA and upstream and downstream genes. The success of this project will help to uncover the molecular mechanism of NF-YA positively regulating of FT by responding environment factors, and enrich the knowledge understanding flowering regulation theory of woody plants. Furthermore, the success of this project can also provide theoretical support and target parameters to develop techniques of flower regulation, genetic improvement and precision cultivation in citrus production.