Molecular characterization of stress-inducible PLATZ gene from soybean (Glycine max L.)

PLATZ (plant AT-rich sequence and zinc-binding protein) is a novel class of DNA-binding proteins; however, the function of the PLATZ gene has not yet been identified in plants. This study aims to isolate, sequence, and analyse the PLATZ gene responsive to abiotic stress in soybean. We isolated a stress-inducible gene encoding the PLATZ from soybean (Glycine max L.). This gene, designated as GmPLATZ1, was specifically induced by drought, high salinity, or abscisic acid (ABA) in soybean. GmPLATZ1 cDNA is composed of 711 bp nucleotide sequences encoding a PLATZ protein (236 amino acids) with 9.41 pI and 26.75 kDa. Multiple sequence alignment analysis showed that the N-terminal region of GmPLATZ1 shares the highly conserved zinc-finger motifs with other PLATZ proteins. The subcellular localization of the GmPLATZ1 protein was analysed via the green fluorescent protein (GFP)- GmPLATZ1 fusion protein in tobacco plant cell. The GFP-GmPLATZ1 protein was shown to be targeted to the nucleus. The function of the GmPLATZ1 gene was further investigated using the overexpression transgenic Arabidopsis. The germination rate in transgenic plants overexpressing GmPLATZ1 was significantly delayed in media supplemented with mannitol compared with that of wild-type (WT) plants. Moreover, cotyledon development in the GmPLATZ1-overexpression transgenic plants was remarkably retarded in the presence of ABA compared to WT. This shows that GmPLATZ1 is implicated in developmental processes such as germination under osmotic stress conditions in plants.