Molecular cloning and characterization of novel WIN1/SHN1 ethylene responsive transcription factor HvSHN1 in barley (Hordeum vulgare L.)

Barley (Hordeum vulgare L.) is the fourth major cereal crop and shows high adaptive capabilities to diverse environments. Thus, it might represent a potential reservoir of novel genes to improve abiotic stress tolerance. In this study, a novel AP2/ERF transcription factor gene designated as HvSHN1 was isolated from barley. Protein sequence analysis showed that the HvSHN1 protein contained a nuclear localization signal and the conserved AP2/ERF domain. Phylogenetic analysis showed that HvSHN1 belongs to the group Va protein in the ERF subfamily which contains the Arabidopsis genes (SHN1, 2 and 3) and the wheat gene TdSHN1 with which it has 94.7% protein sequence identity. Expression profile analysis revealed that HvSHN1 is strongly induced by heat, cold, salt and drought. Transient expression using tobacco BY-2 protoplast coupled to confocal microscopy analysis revealed that HvSHN1 is exclusively targeted to the nucleus. Interestingly, when constitutively expressed in transgenic tobacco, HvSHN1 up-regulated stress responsive genes known to harbor GCC or DRE motif in their promoter regions. Therefore, HvSHN1 might represent a potential candidate for improvement of abiotic stress tolerance in economically important crops.