SEPALLATAGruppen

SEPALLATAGruppen refers to a subgroup of plant MADS-box transcription factor genes known as the SEPALLATA (SEP) family. These genes are classified as E-class genes in the ABCDE model of flower development and play a central role in specifying floral organ identity and the formation of the floral meristem in flowering plants.

In the model plant Arabidopsis thaliana, the SEP family is traditionally represented by four members: SEP1, SEP2, SEP3, and SEP4. Many other plant species possess one or more SEP-like genes, sometimes with additional paralogs, reflecting gene duplication and diversification within this family. SEP genes are typically expressed in developing floral organs and are required for the proper development of petals, stamens, and carpels, as well as for maintaining floral meristem activity.

Mechanistically, SEP genes function as transcription factors that form higher-order protein complexes. They often interact with proteins from the A-class, B-class, and C-class MADS-box families to create tetrameric complexes that regulate downstream target genes involved in organ identity and organogenesis. The E-class function is needed across multiple whorls, contributing to the seamless formation of sepals, petals, stamens, and carpels and to overall floral architecture.

Evolutionary studies show that SEP genes are highly conserved across angiosperms, yet gene duplication and subsequent subfunctionalization or neofunctionalization have contributed to diversity in floral forms. Their study has been pivotal for the understanding of the ABCDE model of flower development and the evolution of flower morphology in flowering plants.