Abstract: FLOWERING LOCUS VE (FVE), one of the autonomous pathway members in Arabidopsis thaliana, promotes the floral transition by inhibiting transcriptional expression of FLOWERING LOCUS C (FLC) at the chromatin level. FLC acts as a key repressor of oral transition by blocking the expression of integrator genes. Howerver, Medicago truncatula lacks the FLC gene. Therefore, the molecular mechanism underlying the regulation of flowering time by FVE homolog in M. truncatula remains to be elucidated. There were two FVE homologs in Medicago truncatula, named MtFVEa and MtFVEb, respectively, and they both had a typical WD40 protein binding domain. Subsequently, qRT-PCR and semi-quantitative RT-PCR analysis revealed that both MtFVEa and MtFVEb were highly expressed in flower and shoot apices. Yeast double-hybrid assay showed that MtFVEa interacted with MtFLD (FLOWERING LOCUS D, a homologous protein of Arabidopsis FLD) and MtHDA6 (histone deacetylase 6, a homologous protein of Arabidopsis HDA6), suggested that MtFVE may be involved in flowering time regulation by forming the FVE-FLD-HDA6 complex in M. truncatula. The research provided ideas and theory for further research on the function of MtFVE in M. truncatula.

Key words: M. truncatula, MtFVE, FVE-FLD-HDA6

摘要： 拟南芥（Arabidopsis thaliana）中自主通路成员FLOWERING LOCUS VE（FVE）主要通过表观遗传学机制抑制其下游开花抑制子FLOWERING LOCUS C（FLC）的表达从而促进开花，但有研究发现蒺藜苜蓿（Medicago truncatula）中没有FLC的同源基因，因此，蒺藜苜蓿中FVE同源基因调控开花时间的分子作用机理还有待研究。通过生物信息学方法在蒺藜苜蓿中筛选到2个拟南芥FVE的同源蛋白，将其分别命名为MtFVEa和MtFVEb。经氨基酸序列比对发现，2个蛋白均具有典型的WD40蛋白结合结构域。随后通过qRT-PCR和半定量RT-PCR检测MtFVEa和MtFVEb基因组织表达特异性，发现2个基因在花和营养生长期的茎尖具有较高水平的表达。经酵母双杂实验进一步分析发现，MtFVEa蛋白与MtFLD \[拟南芥FLOWERING LOCUS D（FLD）的同源蛋白\] 和MtHDA6 \[拟南芥histone deacetylase 6（HDA6）的同源蛋白\] 均发生蛋白互作，表明MtFVE可能同样形成FVE-FLD-HDA6三元复合体参与蒺藜苜蓿开花调控。研究结果为进一步探索蒺藜苜蓿MtFVE基因的功能提供了研究思路和理论支持。

关键词: 蒺藜苜蓿, MtFVE, FVE-FLD-HDA6