E-class MADS-box genes, SEPALLATA (SEP), participate in various aspects of plant development together with B-, C- and D-class MADS-box genes. IiSEP4, a homologous gene of SEP4, was cloned from Isatis indigotica. IiSEP4 was highly expressed in sepals, and its mRNA was mildly detected in leaves, inflorescences, flowers, stamens and young silicles. Constitutive expression of IiSEP4 in Arabidopsis thaliana caused early flowering, accompanied by the reduction of flowers and floral organs. Moreover, the sepals in some flowers were transformed into carpelloid structures with stigmatic papillae, and obviously accompanied by ovule formation. Yeast two-hybrid assays demonstrated that IiSEP4 interacts with other woad MADS proteins to determine the identity of floral organs. These findings reveal the important roles of IiSEP4 in floral development of I. indigotica. The results of this study can lay a foundation for further study on biological functions of MADS transcriptional factors in I. indigotica.

E级MADS-box基因SEPALLATA（SEP）与B级，C级和D级MADS-box基因一起参与植物发育的各个方面。IiSEP4的同源基因SEP4，从克隆菘蓝。IiSEP4在萼片中高表达，并在叶片，花序，花，雄蕊和幼小粉刺中轻度检测到其mRNA。IiSEP4在拟南芥中的组成型表达引起早期开花，并伴有花和花器官的减少。此外，一些花的萼片被转化为带有具乳头状乳突的类胡萝卜素结构，并明显伴随着胚珠的形成。酵母双杂交测定法证明IiSEP4与其他woad MADS蛋白相互作用以确定花器官的身份。这些发现揭示的重要作用IiSEP4在花发育菘蓝。这项研究的结果可以在躺在的MADS转录因子生物学功能的进一步研究奠定了基础菘蓝。