Isolation and Characterization of Orthologs and Promoters from the Distylous .

Common buckwheat () produces distylous flowers with undifferentiated petaloid tepals, which makes it obviously different from flowers of model species. In model species , () is expressed in petal and stamen and specifies petal and stamen identities during flower development. Combining with our previous studies, we found that small-scale gene duplication (GD) event and alternative splicing (AS) of common buckwheat orthologs resulted in , and . and were mainly expressed in the stamen of thrum and pin flower. Promoters functional analysis suggested that intense GUS staining was observed in the whole stamen in transgenic , while intense GUS staining was observed only in the filament of stamen in transgenic These suggested that and had overlapping functions in specifying stamen filament identity and work together to determine normal stamen development. Additionally, and owned the similar ability to rescue stamen development of mutant, although AS resulted in a frameshift mutation and consequent omission of the complete PI-derived motif and euAP3 motif of . These suggested that the MIK region of -like proteins was crucial for determining stamen identity, while the function of -like proteins in specifying petal identity was gradually obtained after Orthologs acquiring a novel C-terminal euAP3 motif during the evolution of core eudicots. Our results also provide a clue to understanding the early evolution of the functional specificity of euAP3-type proteins involving in floral organ development in core eudicots, and also suggested that holds the potential application for biotechnical engineering to develop a sterile male line of