Molecular characterization, modeling and expression analysis of a somatic embryogenesis receptor kinase (SERK) gene in Momordica charantia L. during somatic embryogenesis

Somatic embryogenesis receptor kinase (SERK) gene is known to be a marker of somatic embryogenesis in several plant species. The present study reported the isolation and characterization of a SERK gene ortholog, designated as McSERK, in Momordica charantia, an important medicinal plant. The complete coding region of McSERK was found to encode a 627 amino acid protein which contained an N-terminal signal peptide, a leucine zipper, five leucine rich repeats, a serine-proline-proline domain, a transmembrane domain, a kinase domain and the C-terminal region, depicting the typical characteristic features of SERK-family proteins. Phylogenetic analysis suggested that McSERK was highly similar to the SERK proteins of Cucumis sativus, Glycine max and Medicago truncatula. Homology modeling was attempted to construct the three dimensional structure of McSERK protein which showed that it corresponded to a monomeric protein. McSERK expression was high in embryogenic callus but its expression was relatively low in different plant organs. The high expression of McSERK transcript in the embryogenic callus confirmed its association with somatic embryogenesis in M. charantia.