No abstract

a b s t r a c tBased on our microarray-analysis results of the salt tolerant wheat mutant, RH8706-49, an unknown salt-induced gene containing a conserved DUF662 domain was identified and cloned; we named this gene TaSRG (Triticum aestivum Salt Response Gene). Real-time quantitative PCR analyses showed that the expression of this gene was affected by salt, drought, cold, ABA and other stress conditions. The overexpression of TaSRG in wild-type Arabidopsis resulted in increased salt tolerance compared with wild-type plants. In addition, subcellular localisation revealed that TaSRG encodes a protein that was found mainly in the nucleus. Our results suggest that wheat TaSRG might encode a transcription factor that could be utilised for enhancing stress tolerance in a wide range of plants.

The gene expression chip of a salt-tolerant wheat mutant under salt stress was used to clone a salt-induced gene with unknown functions. This gene was designated as TaSR (Triticum aestivum salt-response gene) and submitted to GenBank under accession number EF580107. Quantitative polymerase chain reaction (PCR) analysis showed that gene expression was induced by salt stress. Arabidopsis and rice (Oryza sativa) plants expressing TaSR presented higher salt tolerance than the controls, whereas AtSR mutant and RNA interference rice plants were more sensitive to salt. Under salt stress, TaSR reduced Na(+) concentration and improved cellular K(+) and Ca(2+) concentrations; this gene was also localized on the cell membrane. β-Glucuronidase (GUS) staining and GUS fluorescence quantitative determination were conducted through fragmentation cloning of the TaSR promoter. Salt stress-responsive elements were detected at 588-1074 bp upstream of the start codon. GUS quantitative tests of the full-length promoter in different tissues indicated that promoter activity was highest in the leaf under salt stress. Bimolecular fluorescence complementation and yeast two-hybrid screening further showed the correlation of TaSR with TaPRK and TaKPP. In vitro phosphorylation of TaSR and TaPRK2697 showed that TaPRK2697 did not phosphorylate TaSR. This study revealed that the novel TaSR may be used to improve plant tolerance to salt stress.