Cloning and characterization of a cDNA encoding 14-3-3 protein with leaf and stem-specific expression from wheat

The 14-3-3 proteins, originally described as the mammalian brain proteins, are ubiquitous eukaryotic proteins and have been shown to exert an array of function. A great number of 14-3-3 sequences have been reported in Eudicotyledon. The data of 14-3-3 from the monocotyledon plants, however, are limited. In this report, a 14-3-3 cDNA (designated as Ta14A) was isolated from wheat. An extensive search in GenBank database revealed another 14 14-3-3 isoforms from monocotyledonous plants. These proteins plus 14-3-3 isoforms from Arabidopsis were used for phylogenetic reconstruction, which revealed two groups of 14-3-3 proteins in monocotyledonous plants, namely epsilon and non-epsilon, respectively. The epsilon isoforms were present in monocotyledonous plants. Therefore, the gene duplication to result in an epsilon and non-epsilon isoforms was likely to take place before the speciation of monocotyledon and Eudicotyledon plants. Structural analysis indicated that the different conserved domains and structural characters existed in the monocotyledon 14-3-3 isoforms, which will affect their interaction with other effector proteins. Ta14A was strongly expressed in leaf and stem, undetected in root, suggesting it may have the unique functions within these tissues. These data suggest that structure difference and spatial expression of 14-3-3 will be the important factors to confine its functional specificity.