Expression and promoter analysis of the TaLTP1 gene induced by drought and salt stress in wheat (Triticum aestivum L.)

In a previous report, a gene encoding lipid transfer protein (LTP), TaLTP1, was characterized as induced by dehydration in a 2BS/2RL wheat-rye translocation. For the further study of this gene, gene expression and promoter analysis under water stress treatments were performed. Transcripts of the TaLTP1 gene were increased by water stresses, such as by treatment at several PEG concentrations and NaCl, by hormone treatments (SA, ethephon), by H ₂O₂, or by wounding. The TaLTP1 gene did not contain any intron sequences as compared with its cDNA and genomic DNA sequence. Sequence analysis of the TaLTP1 promoter was performed from the 2856 bp upstream of the transcription start site. A series of five 5′ deletions of the TaLTP1 gene promoter were amplified with each of five upstream primers and one downstream primer and fused with GUS reporter gene on the pBI101 binary vector. All of the five deletions showed similar GUS activity, which was higher than those of mock treatment during drought or salt treatment. These results showed that 337 bp DNA fragment of the upstream region have drought and salt stress-responsive elements. The 337 bp fragment region contained five putative MYC-like and one MYB-like sequences. Therefore, cis-elements located in the 337 bp DNA fragment within promoter region may control the transcription of the TaLTP1 gene during dehydration and periods of salt stress in wheat.