A novel wheat S1-bZIP gene, TabZIP11 confers stress resistance in Arabidopsis

Abstract

The majority of basic leucine zipper (bZIP) transcription factor (TF) subgroup S1 play significant regulatory role in response to abiotic stress. However, their functions and underlying molecular mechanisms in abiotic stress responses are less known in wheat (Triticumaestivum L.). In this study, we isolated a TabZIP11 TF, which is from S1 subgroup of wheat bZIP transcription factor. TabZIP11 encodes a nuclear protein without transcriptional activation activity. Transcript of TabZIP11 gene was induced by abscisic acid (ABA), NaCl, and cold stress treatments. Whereas compared with NaCl treatment, TabZIP11 showed a lower expression level under NaCl+LaCl3 condition. We found that calcium-dependent protein kinase1 (TaCDPK1), TaCDPK5, TaCDPK9-1, TaCDPK30 and calcineurin B-like protein (CBL)-CBL-interacting protein kinase31 (TaCIPK31) cooperated with TabZIP11. The overexpression of TabZIP11 ectopically improved salt and freezing tolerances in Arabidopsis. TabZIP11 contributed to salt and freezing tolerance by modulating soluble sugar, proline, hydrogen peroxide (H2O2), and malondialdehyde (MDA) productions and abiotic stress responsive gene expression levels. TabZIP11 can form both homodimers and heterodimers with itself and group C TabZIP members. The modified yeast one-hybrid analysis confirmed that TabZIP36 significantly enhanced the binding ability of TabZIP11 to the promotor of TaCBF1 gene. Thus, these results suggest that TabZIP11 interacts with TabZIP36 to modulate cold signaling by facilitating the transcriptional activity of c-repeat binding factor (TaCBF1) gene. TabZIP11 functions as a positive regulator of salt stress responses through interacting with TaCDPK1/5/9-1/30 and TaCIPK31.