EF2调节拟南芥开花时间的分子机制

开花是植物营养生长至生殖生长的重要转变过程，由外界环境和内在生理状态共同调控完成，植物能否在恰当时间开花，决定了植物能否有效产生种子，延续下一代。组蛋白甲基化和组蛋白变体H2A.Z是调控拟南芥开花的重要方式之一，我们前期通过筛选到突变体early flowering 2 (ef2)，ef2在FRIGIDA背景下有明显的早花表型。EF2编码SET结构域蛋白，酵母双杂交和蛋白体外pull-down研究显示：EF2能与SWR1复合体的ARP6亚基直接互作。FRI ef2 arp6的表型与FRI ef2表型一致，表明二者在同一个开花途径，共同调控着FLC的表达水平。进一步研究显示：ef2突变体内H2A.Z的水平降低，表明EF2能够调控H2A.Z的富集。本研究拟在已有的基础上，阐述EF2调控拟南芥开花时间的机理，探究组蛋白甲基化和H2A.Z协同调控的分子机制。

The timing of flowering, the transition from vegetative to reproductive development in plants, is determined by genetic pathways that integrate endogenous and environmental signals. Flowering time is an important agronomic trait for regional and seasonal adaption, and heading at the proper time is a critical step for successful grain production. The histone methylation and histone variant H2A.Z are critical in flowering-time regulation in Arabidopsis. Here, we found an early flowering 2 (ef2), which exhibited the early flowering phenotype after crossed ef2 into FRIGIDA. EF2, encoding a SET domain protein, a putative histone lystine methyltransferase. EF2 interacts with ARP6, which is a subunit of SWR1. The possible genetic interaction between EF2 and APR6 was investigated by crossing apr6 into FRI ef2. The FRI ef2 arp6 double mutant displayed the early flowering, which is similar to that of FRI ef2, suggesting that EF2 acts the same pathway as ARP6 in flowering time. We investigated the distribution of H2A.Z by chromatin immunoprecipitation (ChIP), followed by quantitative PCR measurement of DNA enrichment. H2A.Z levels were reduced in ef2 mutant, suggesting that EF2 was involved in histone variant H2A.Z regulation. This study is going to study the roles of EF2 in flowering time and figure out the relationship between histone methylation and H2A.Z.