Genome-wide analysis of key salinity-tolerance transporter (HKT1;5) in wheat and wild wheat relatives (A and D genomes)
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Exclusion of sodium ions from cells is one of the key salinity tolerance mechanisms in plants. The high-affinity cation transporter (HKT1;5) is located in the plasma membrane of the xylem, excluding Na+ from the parenchyma cells to reduce Na+ concentration. The regulatory mechanism and exact functions of HKT genes from different genotypic backgrounds are relatively obscure. In this study, the expression patterns of HKT1;5 in A and D genomes of wheat were investigated in root and leaf tissues of wild and domesticated genotypes using real-time PCR. In parallel, the K+/Na+ ratio was measured in salt-tolerant and salt-sensitive cultivars. Promoter analysis were applied to shed light on underlying regulatory mechanism of the HKT1;5 expression. Gene isolation and qPCR confirmed the expression of HKT1;5 in the A and D genomes of wheat ancestors (Triticum boeoticum, AbAb and Aegilops crassa, MMDD, respectively). Interestingly, earlier expression of HKT1;5 was detected in leaves compared with roots in response to salt stress. In addition, the salt-tolerant genotypes expressed HKT1;5 before salt-sensitive genotypes. Our results suggest that HKT1;5 expression follows a tissue- and genotype-specific pattern. The highest level of HKT1;5 expression was observed in the leaves of Aegilops, 6 h after being subjected to high salt stress (200 mM). Overall, the D genome allele (HKT1;5-D) showed higher expression than the A genome (HKT1;5-A) allele when subjected to a high NaCl level. We suggest that the D genome is more effective regarding Na+ exclusion. Furthermore, in silico promoter analysis showed that TaHKT1;5 genes harbor jasmonic acid response elements.
KeywordsSalt tolerance Na+ transporter Wheat Wheat ancestors
The authors would like to thank the Institute of Biotechnology for supporting this research and the Bioinformatics Research Group in the College of Agriculture (Shiraz University). We thank Dr. Mehrabi (Ilam University) for kindly supplying seeds of wild genotypes for this study. We thank Mr. Amin Ramezani for help in performing the real-time PCR experiments.
- Byrt CS (2008) Genes for sodium exclusion in wheat. Ph.D. thesis, University of Adelaide. Available from http://hdl.handle.net/2440/56208. Accessed 24 April 2012
- Deihimi T, Niazi A, Ebrahimi M, Kajbaf K, Fanaee S, Bakhtiarizadeh MR (2012) Finding the undiscovered roles of genes: an approach using mutual ranking of coexpressed genes and promoter architecture-case study: dual roles of thaumatin like proteins in biotic and abiotic stresses. SpringerPlus 1:30CrossRefGoogle Scholar
- Ghavami F, Malboobi MA, Ghanadha MR, Yazdi-samadi B, Mozaffari J, Jafar-Aghayi M (2004) Evaluation of salt tolerance of Iranian wheat cultivars at germination and seedling stages. Iranian Journal of Agricultural Sciences 35(2):453–464Google Scholar
- Ramezani A, Niazi A, Abolimoghadam AA, Zamani Babgohari M, Deihimi T, Ebrahimi M, Akhtardanesh H, Ebrahimie E (2012) Quantitative expression analysis of TaSOS1 and TaSOS4 genes in cultivated and wild wheat plants under salt stress. Mol Biotechnol (in press)Google Scholar
- Tabatabaei SMF, Maassoumi TR (2001) Triticum boeoticum ssp thaoudar exist in Iran. Cereal Res Commun 29:121–126Google Scholar