Expression analysis of FaesSTK gene in Fagopyrum esculentum Moench with long pistil and stamen

Using RACE technology, three flower types of STK homologous gene FaesSTK (GenBank accession number:MN597104) were examined from Fagopyrum esculentum Moench, and their sequence characteristics were analyzed. Sequence alignment results suggested that the sequences of the gene from the three flower types were identical. The gene was 967 bp in length and contained a 689 bp open reading frame (ORF) encoding 225 amino acids. Protein sequence alignment and phylogenetic analyses grouped the FaesSTK protein into the STK linage of D-class MADS-box transcription factors. FaesSTK contained a highly conservation MADS domain with 57 amino acids, a secondary conserved K-domain with 82 amino acids, as well as two highly conserved motifs (AGⅠ motif and AGⅡ motif) in the variable C-terminal region. In addition, quantitative real-time polymerase chain reaction (qRT-PCR) revealed that the FaesSTK gene was mainly expressed in the stamen, gynoecium, and young fruits at different developmental stages in the F. esculentum lpls mutant. Moreover, FaesSTK was weakly transcribed in the root and tepal but was absent in the leaf and stem. FaesSTK expression levels in the gynoecium and fruit were significantly higher than that in other tissues. Our data suggest that FaesSTK may play a major role in the development of the gynoecium and fruit of the F. esculentum lpls mutant.