关键词: 普通小麦, TabZIP3, 胁迫诱导表达, 耐盐性

Abstract: Basic leucine zipper (bZIP) transcription factors (TF) are major TF families in plants with diverse functions, but only limited reports are available about the RF2 subfamily bZIP proteins. In this study, total RNA from leaves of common wheat cv. Chinese Spring was isolated and reversely transcribed into cDNA to amplify the cDNA sequence of TabZIP3 by RT-PCR combining with RACE (rapid amplication of cDNA end) technique. The open reading frame (ORF) of TabZIP3 was 1 020 bp in length and encoded 339 amino acid residues. Conserved domain prediction indicated that TabZIP3 was a member of RF2 subfamily of bZIP proteins. Phylogenetic analysis showed that TabZIP3 had the closest relationship with RF2b in rice. The GFP-TabZIP3 fusion protein was localized to the cell membrane in tobacco epidermal cells. RT-PCR analysis showed that the expression of TabZIP3 was induced by NaCl and PEG6000. Gus staining of the TabZIP3promoter: Gus transgenic Arabidopsis plants also showed the inducible expression of TabZIP3 by NaCl stress. To study the function of TabZIP3, TabZIP3-overexpression vector was constructed and transformed into Arabidopsis ecotype Col-0. When the seeds of TabZIP3-overexpressed Arabidopsis plants and the wild type were germinated on MS medium containing 150 mmol/L NaCl for 18 d, the TabZIP3-overexpressors grew much better than those of the wild-type control, and much more proline and much lower MDA content were also detected in the Arabidopsis plants overexressing TabZIP3. The above results suggested that the wheat RF2 subfamily bZIP protein gene TabZIP3 was induced by NaCl and PEG treatment and its overexpression led to improved salt stress tolerance in transgenic Arabidopsis plants.

Key words: common wheat, TabZIP3；stress-inducible expression, salt tolerance