Isolation and characterization of Panax ginseng 14-3-3 gene family

14-3-3 proteins are a family of conserved proteins expressed in all eukaryotes. They function as regulators in signaling pathways through protein-protein interaction. These proteins have been implicated in plant metabolism, development, and responses to abiotic and biotic stresses. Here, we isolated six cDNAs encoding 14-3-3 proteins of Panax ginseng, designated as Pg14-3-3, by searching the ginseng EST database. Their degree of amino acid identity ranged from 53 to 84%. Phylogenetic analysis showed that the Pg14-3-3 isoforms can be divided into two groups by early duplication, with one group being further split into three subgroups because of subsequent duplication events. Pg14-3-3s are differentially expressed in various root tissues and leaves, and their transcript levels are up- or down-regulated by either cold or drought stresses. These results suggest a possible role for Pg14-3-3 proteins in abiotic stress responses.