Hajer Ziadi and Brini Faical
University of Sfax, Tunisia
Posters & Accepted Abstracts: J Neurosci Neuropharm
Salinity stress limits the growth and productivity of agricultural crops in many regions of the world. The ionNa+ is a small molecule that is easily absorbed into root tissues of higher plants and transported throughout plant organs. Over-accumulation of sodium in the cytosol causes ion damage, osmotic stress and inhibition of biochemical and physiological processes. Salt tolerance of plants depends on HKT transporters (High-affinity K+ Transporter), which mediate Na+-specific transport or Na+-K+ co-transport. The family of membrane transporters named HKT is permeable either to K+ and Na+ or to Na+ only has been shown to play important roles in these functions. Contrary to Arabidopsis that possesses a single HKT transporter, cereals possess a much larger number of HKT genes, nine genes in rice (Oryza sativa) and five to 11 in the different wheat genomes. Here, we isolated two transporters (HKT 2.1 and HKT 2.3) cDNAs from a salt-tolerant durum wheat (Triticum turgidum L. subsp. durum) cultivar, Om Rabia3. At amino acid sequence level, the TdHKT2;1 and TdHKT2;3 have 99% identity to those published in Gene Bank. The two transports have been isolated and cloned in the pGEM-easy vector. Since the alignment of the protein sequence of TdHKT2;1 and TdHKT2;3 also showed the presence of glycine in the first pore domain, which made it possible to conclude that this transporter should be permeable to K+ and also to Na+. Also, we investigated the regulation of the gene TdHKT2.1 of Triticum durum. A 500-bp genomic fragment upstream of the TdHKT2.1 translated sequence has been isolated, cloned, and designated as the “PrTdHKT12.1” promoter. Sequence analysis of “PrTdHKTt2.1”revealed the presence of cis-regulatory elements which could be required for abiotic stress, abscisic acid (ABA) and jasmonic acid (JA) responsiveness
