龙眼胚性愈伤组织中ELF4家族基因克隆及其表达分析

ELF4家族是植物特有基因，能调节生物钟、调控开花时间、感受光周期和参与幼苗去黄化等。以龙眼松散型胚性愈伤组织为材料，采用RT-PCR结合RACE法克隆了ELF4家族3个成员cDNA全长，分别命名为DlELF4、DlELF4-LIKE 1和DlELF4-LIKE 4。DlELF4全长599 bp，编码140个氨基酸；DlELF4-LIKE 1全长762 bp，编码142个氨基酸；DlELF4-LIKE 4全长661 bp，编码114个氨基酸；DlELF4家族成员均为不稳定的亲水蛋白，无信号肽与跨膜结构，都含有DUF1313保守功能结构域。进化树分析表明，植物中ELF4家族可分成二个亚组，ELF4与ELF4-LIKE 1聚为一组，ELF4-LIKE 2、3、4聚为另一组。qPCR结果表明：在体胚发生过程中DlELF4、DlELF4-LIKE 1和DlELF4-LIKE 4表达模式相同，均在球形胚时期表达量极高，而在其它时期表达量很低；DlELF4家族对不同光质和不同处理时间的响应存在差异：DlELF4的表达经24 h处理时可能受绿光和红光诱导，经72 h处理时可能受红光、蓝光和白光诱导；DlELF4-LIKE 1的表达在24 h处理时可能受绿光诱导，经72 h处理时受红光和绿光抑制；DlELF4-LIKE 4的表达在24 h和72 h处理时可能受蓝光和白光诱导。水杨酸和茉莉酸甲酯能促进龙眼胚性愈伤组织中DlELF4家族成员的表达。以上结果表明，ELF4家族可能参与龙眼体胚发生过程中球形胚的形态建成与胁迫应答。

Cloning and Characterization ofELF4Family Genes from Embryogenic Callus inDimocarpus longan Lour.

ELF4 family has not been detected outside the plant kingdom, and it is involved in the promotion of circadian clock, flowering time, photoperiod perception and seedling de-etiolating. The RT-PCR combined with RACE method was used to obtain the complete 3 cDNA sequences of ELF4 family's from the embryogenic callus in Dimocarpus longan. The complete cDNA sequence of DlELF4 was 599 bp, encoding 140 amino acids, and that of DlELF4-LIKE 1 and DlELF4-LIKE 4 was 762 bp, encoding 142 amino acids, and 661 bp, encoding 114 amino acids, respectively. DlELF4, DlELF4-LIKE 1 and DlELF4-LIKE 4 were unstable and hydrophilic proteins, without signal peptides and transmembrane structures, but had the DUF1313 protein function domain. Anglicizing phylogenetic tree of ELF4 family in plants indicated that ELF4 family can be divided into two subgroups. ELF4 and ELF4-LIKE 1 was gathered as one group, while ELF4-LIKE 2, 3 and 4 were clustered into another group. qPCR results indicated that DlELF4 family showed the same expression pattern during the somatic embryogenesis, they expressed at the highest levels in the globular embryos, but very low levels in other embryogenic stages. DlELF4 family showed different responses with different light quality and treatment time. DlELF4 may be induced by the green and red light after 24 h treatment and may be induced by the red, blue and white light after 72 h; DlELF4-LIKE 1 may be induced by the green light after 24 h treatment, but may be suppressed by the red and green light after 72 h; DlELF4-LIKE 4 may be induced by the blue and white light after 24 and 72 h treatment. DlELF4 family makes the positive response with SA and MJ treatment. The above results showed that ELF4 family might participate in globular embryoid's morphogenesis during somatic embryogenesis and stress responses.