The role of cis-acting elements of the promoter region in regulating the spatio-temporal expression of the salinity stress-responsive NHX1 gene in Triticum aestivum L.

Soil salinity is one of the most serious issues in wheat cultivation in Iran, which has a detrimental impact on crop production and plant growth. To investigate genes associated with the response to salinity stress in wheat, 3567 expressed sequence tags (ESTs) were analyzed from salinity-tolerant wheat leaf and root libraries collected from the Harvard University Database. EGassembler, CLCbio and IDEG6 softwares were used to analyze gene expression and the GoMapMan comparative classification tool was used to classify functional catalogs. Statistically significant differences were observed between the genes of the two libraries in 7 functional groups. The results showed that NHX1 ion exchangers play an important role in ion homeostasis and salinity stress tolerance in both leaf and root tissues. Because a full understanding of the gene transcription regulation system depends on functional analysis of cis-acting elements, the regulatory elements in the 5' regulatory region of the NHX1 genes were identified using Plant CARE databases. Several regulatory elements related to biological processes, hormonal regulation, and stress response and environmental stimuli were identified. This study provides an insight into the role of the promoter’s cis-acting in regulating the spatio-temporal expression of NHX1 gene under salinity stress.