Cloning, characterization and expression analysis of a 7S globulin gene in mesocarp of oil palm (Elaeis guineensis Jacq.).

Abstract Oil palm ( Elaeis guineensis Jacq.) is one of the highest oil-yield crops in the world. Based on previous work on suppression subtracted hybridization library construction and analysis between mesocarp and kernel of oil palm fruits, the full-length cDNA of 7S globulin was obtained via rapid-amplification of cDNA ends. The gene, OPALM7SG1 (GenBank accession No. JN896330 ), encodes a polypeptide of 248 amino acids. The amino acid sequence of 7S globulin showed high homology with the sequence of 7S globulin from oil palm embryos in previous reports, and the amino acid composition of OPALM7SG1 revealed that it contained almost all kinds of amino acids, including high levels of glutamic acid, arginine and serine, and low levels of sulfur-containing amino acids cysteine and methionine. Real-time fluorescent quantitative PCR indicated that OPALM7SG1 was highly expressed in the fourth stage of oil palm mesocarp development (120–125 days after flowering), but remained at relatively low levels in the other four stages. This differential expression of OPALM7SG1 was essential for the accumulation of 7S globulin in the mesocarp of oil palm fruits. The full-length of 7S globulin identified in the present study and the results of its differential expression will be a good foundation for further study on functional analysis and genetic modification of 7S globulin during fruit development of oil palm.