杨树 NF-Y 转录因子在成花诱导中的作用及分子调控机制

Floral induction is a key process in plant floral development, which directly controls of flowering time. Poplar is an important tree species of great economic and ecological importance worldwide. It has a long juvenile period, which resulting in limitation of progress in genetics and breeding. Therefore, research on the biological function of the NF-Y in floral induction and the molecular mechanisms in Populus, which stimulate precocious flowering and shorten breeding period can effectively accelerate the genetic improvement cycle. In this project, we are going to investigate the role and function of NF-Y transcription factors in plant floral development process by using RT-PCR, protoplast transient transformation, yeast two-hybrid, bimolecular fluorescence complementation and transgenic technology in the transgenic and wild-type Populus. Specifically, the spatial and time dynamics of NF-Ys, interactions situation, flowering phenotype will be investigated in transgenic and wild-type plants. The results of this investigation will help us to recognize the role and function of the transcription factor NF-Ys in floral induction process. The findings from this study can provide valuable information to dramatically speed up tree breeding programs.

成花诱导是植物花发育的一个关键过程，直接控制着开花时间。杨树作为重要的经济和生态树种，遗传性状改良和新品种选育受到较长幼年期的限制。因此，研究杨树NF-Y (Nuclear Factor Y) 转录因子在成花诱导中的作用和分子调控机制，促进早花，缩短幼年期，可以有效地加速遗传改良周期。本项目拟以杨树无性系和转基因株系为试材，运用定量RT-PCR、瞬时转化、酵母双杂交和双分子荧光互补技术，以生物信息学预测及表达特异性分析为切入点，利用筛选到的参与成花诱导的NF-Y亚型（PtNF-YA11，PtNF-YB1和PtNF-YC15），从分子、细胞水平研究其功能和信号途径；同时结合NF-Y与CO互作及转基因实验探讨两者遗传学关系，项目旨在阐明杨树NF-Y转录因子参与成花诱导的分子调控机制。研究结果将有助于人们认识NF-Y转录因子在成花诱导中的作用，为调控林木开花时间、缩短育种周期提供可靠的理论依据。

成花诱导的调控机制一直是花发育研究领域的重大科学问题，也是植物生殖与发育生物学研究的热点和难点。多年生木本植物成花诱导过程明显不同于一年生草本植物。杨树新品种选育一直是林木育种研究的重点，但较长的幼年期是限制其遗传改良及品种选育工作的主要因子。本研究目标是阐明NF-Y转录因子在杨树成花诱导中的作用和分子调控机制。重要结果如下：首先，通过系统进化分析、功能域分析、表达特异性分析以及亚细胞定位分析，预测杨树NF-Ys相关成员PtNF-YA11，PtNF-YB1，PtNF-YC16可能参与杨树成花诱导的调控；其次，利用遗传转化技术，证实重要候选基因PtNF-YB1参与了植物成花诱导的调控，表现为早花现象；最后，综合利用在线预测互作网站STRING、酵母双杂交实验（Y2H）和双分子荧光互补实验（BiFC）证实了PtNFYB1和PtCO1、PtCO2相互作用关系，结合花期促进基因CO、FT和SOC1转录表达分析，阐明了其调控机制和作用模型。研究结果将对于人们认识NF-Y转录因子家族在木本植物中的作用和功能具有重要意义，为调控林木开花时间、缩短育种周期提供重要理论依据。