Sequence Analysis and Expression Profiling of 14-3-3 Genes from the Extremophile Thelungiella salsuginea, Ecotype Yakutsk

Members of the 14-3-3 protein family are known to be important regulators of plant primary metabolism, hormonal signal transduction, and ion homeostasis. We identified nine isoforms of 14-3-3 genes of Thellungiella salsuginea, an extremophile relative of Arabidopsis thaliana. All the identified isoforms were designated according to their Arabidopsis orthologs: Chi, Omega, Psi, Phi, Upsilon, Lambda, Mu, Epsilon, and Omicron. Comparison of the deduced amino acid sequences reveals high degree of identity between the members of this protein family. Isoforms, designated as Ts14-3-3 Chi, Omicron, and Mu, display noticeable differences in their C-terminal domain as compared to their Arabidopsis homologs. Phylogenetic analysis demonstrated that the identified isoforms split into two groups, epsilon and non-epsilon, according to the common classification of the 14-3-3 family genes. The Thellungiella 14-3-3 isoforms are differentially expressed in various plant tissues, and real-time RT-PCR revealed that most of the isoforms are highly expressed even under normal growth conditions. In response to abiotic stress, low temperatures and high concentrations of salts, 14-3-3 genes exhibited different expression patterns. Our data suggest that, due to the high expression levels of the 14-3-3 genes, Thellungiella plants are likely pre-adapted to the stress conditions. Differences between the C-terminal domains of some Thellungiella 14-3-3 proteins and their Arabidopsis homologs may result in differences in target protein specificity. © 2012 Pleiades Publishing, Ltd.