Abstract：Stress responsive NAC transcription factors involve in plant abiotic stress tolerance. Overexpression of SNAC1 significantly enhances drought, cold and salinity resistance in transgenic rice(Oryza sativa). In this study, TaSNAC1 was obtained from common wheat (Triticum aestivum) by homology-based cloning, its sub-celluar localization was analyzed, and its expression patterns in different tissues and under PEG or salt stress were investigated by quantitative RT-PCR. The cDNA of amplified TaSNAC1 including complete CDS was 1 076 bp in size, and the gDNA was 1 222 bp including a 146 bp intron (GenBank accession No. JN621240). TaSNAC1 encoded a protein with 329 amino acids, which showed 97.3%, 86.3%, 81.1%, 79.1% and 79.2% identity with SNAC1 of barley(Hordeum vulgare), false brome(Brachupodium distachyon), rice, maize(Zea mays) and sorghum(Sorghum bicolor), respectively. Results of phylogenetic analysis showed that TaSNAC1 was different from other wheat NAC transcription factors, it was clustered into a separate clade with other grass stress-responsive NAC. Structure prediction showed that TaSNAC1 might form a dimer, including a untypical nuclear localization signal (NLS) and a typical no apical meristem (NAM) domain. The core motif "WKATGXDK100-107" was located in a β sheet, which formed a concave surface and confered the ability of DNA binding. Based on transient expression assay using Arabidopsis thaliana mesophyll protoplasts, we found TaSNAC1 localized in the nucleus specifically. The expression levels of TaSNAC1 in both leaf and root were increased significantly in similar pattern during the application of high salt, and the increase in root was more dramatic (upto ~60 folds in root and ~10 folds in leaf ). Under PEG stress, the transcripts of TaSNAC1 were elevated quickly and sharply in root, but the change in leaf was delayed and the amplitude was decreased (about 15 folds in root and 6 folds in leaf). These data suggest that TaSNAC1 plays a vital role in abiotic stress response, and it possesses potential utility in improving drought and salinity tolerance in wheat.
