紫薇花器官发育调控基因LiFUL1的分离与表达分析

紫薇湘韵具有只开花不结实的特性,表现为花药不开裂、花粉败育、胚珠发育异常。紫薇红叶为普通紫薇,可正常开花结实。以紫薇湘韵为试验材料,采用RT-PCR方法,从花芽中分离得到1个FRUITFULL(FUL)同源基因,命名为LiFUL1(GenBank登录号为MN894547)。序列分析结果表明,其cDNA开放阅读框长度为753 bp,编码251个氨基酸,分子质量为28.453 13 ku。序列比对和保守结构域分析结果表明,LiFUL1基因编码蛋白具有典型的MADS-MEF2和K-box 结构域,C末端含有一个保守性高的基序euFUL MOTIF,因此,LiFUL1属于MADS家族的FUL/AP1亚家族。进化分析表明,紫薇的LiFUL1基因编码的蛋白氨基酸序列与木本植物蓝桉的FUL/AP1氨基酸序列亲缘关系最近。qRT-PCR分析结果表明,LiFUL1基因在紫薇湘韵花器官分化阶段的花萼分化时期、花瓣与雄蕊分化时期、雄蕊与雌蕊分化时期的表达量显著高于紫薇红叶。另外,利用原核表达系统在大肠埃希菌中成功表达了LiFUL1蛋白,为进一步研究LiFUL1基因的功能奠定了基础。

Isolation and expression of floral organ development regulating gene LiFUL1 in Lagerstroemia indica L.

Flowers of crape myrtle Xiangyun are not strong enough to seeding, the manifestations of Xiangyun are indehiscent anther, pollen abortion and abnormal ovule. Redleaf is common crape myrtle with normal flowering and bearing. Crape myrtle Xiangyun was selected as the experimental material, RT-PCR was employed to isolate a homologous gene of FRUITFULL (FUL) from Xiangyun, named as LiFUL1(GenBank accession No. MN894547). Sequence analysis indicated that length of the open reading frame of LiFUL1 cDNA was 753 bp, which encoded a protein with 251 amino acids, its molecular weight was 28.453 13 ku. Analysis of sequence alignment and conserved structural domain showed that LiFUL1 protein belonged to FUL/AP1, a subfamily of the MADS, for it had both typical MADS-MEF2 and K-box domain, and the highly conserved motif euFUL MOTIF at C terminus. Phylogenetic tree analysis revealed that LiFUL1 of crape myrtle was most closely related to Eucalyptus globulus’s FUL/AP1 sequence. qRT-PCR test demonstrated that expressions of LiFUL1 in Xiangyun were significantly higher than those in crape myrtle Redleaf at calyx differentiation, petals and stamens differentiation, stamens and pistils differentiation stages. Successful expression of LiFUL1 in Escherichia coli using the prokaryotic expression system provided a basis for further study of LiFUL1 gene function.