对模式植物拟南芥的研究表明，CONSTANS（CO）基因在植物开花的光周期途径中起中心调控作用。大豆与拟南芥不同，是一种严格的短日照植物，对其开花的分子机理并不清楚，关于大豆的CONSTANS及CONSTANS-LIKE蛋白的序列、结构功能目前尚无文献报导。根据大豆基因组序列和拟南芥CO基因家族序列比对结果，我们从大豆垦农18中分离得到了13个CONSTANS-LIKE（GmCOLs）基因。根据保守的B-box数量和长度，大豆CO家族基因也可以分成三类，即group I（2个B-box）、group II（1个B-box）、group III（1个B-box和1个保守性较低的锌指结构）。在本实验中，我以GmCOL2作为主要研究对象。qPCR结果显示，GmCOL2 mRNA也表现出明显的节律性表达，但表达模式与拟南芥的明显不同，其表达高峰出现在光照开始前后，而拟南芥CO mRNA的表达高峰出现在黑暗开始前；GmCOL2在根部几乎不表达，但在叶片中表达量很高；从大豆的整个生长时期来看，GmCOL2的表达量在第三复叶期有表达高峰。在GFP:GmCOL2转化的拟南芥幼苗中观察到核定位GFP荧光，表明GmCOL2蛋白的定位与拟南芥CO蛋白相同，都是核定位蛋白，可能发挥转录因子的功能。GmCOL2转化拟南芥晚花突变体co-2植株在长日条件下开花时间较突变体提前6天，但转化的野生型植株没有明显的表型。结果表明，大豆GmCOL2至少能部分恢复拟南芥CO的功能，但又有自身的特殊性。

CONSTANS (CO) plays a central role in the flowering photoperiod pathway in the light of the research on Arabidopsis. Glycine max , different from Arabidopsis, is a strict short-day plant. We know little about the flowering molecular mechanism about it and almost no paper has been published so far to discuss the sequences, constructions and functions of Glycine max CONSTANS and CONSTANS-LIKEs. Thirteen genes of CONSTANS-LIKE (GmCOLs) genes were searched out from Glycine max KN18 on the basis of alignment of soybean genome sequence and CO family sequences in Arabidopsis. They were classed into 3 groups according to the conserved B-box: group I (two B-box), group II (one B-box) and groupIII (one B-box and a diverged zinc finger sequence). GmCOL2 was chosen as the major target in the experiment. The qPCR results demonstrated that GmCOL2 mRNA showed obvious circadian but the pattern was different form that of AtCO. There was no transcripts of GmCOL2 detected in roots, whereas GmCOL2 expressed much higher in leaves. It had a expression peak in third trifoliolates phase through the life span. Arabidopsis seedling transformed with GFP:GmCOL2 displayed nucleus located GFP florescent showing that GmCOL2 protein, like AtCO protein, located to nucleus and played a role as transcriptional factor. The flowering time of late-flowering mutant co-2 transformed with GmCOL2 is earlier than parental line under long day conditions. However, the wild type Ler plants transformed by GmCOL2 showed no obvious phenotype on flowering time. The results suggested that GmCOL2 could rescue partially the phenotype of co-2 mutant, but it had its own specific functions.