Isolation and Expression Analysis of Alsos1 Gene Under NaCl Stress in Halophyte Grass Aeluropus Littoralis Parl

We have isolated a Na+/H+ antiporter gene from Aeluropus littoralis under NaCl salt stress. The isolated cDNA is 3981 bp long and contains a 3438 bp open reading frame. The amino acid sequences of PtNHA1 show high identities to SOS1 plant transporters. PtNHA1 is predicted to contain 12 hypothetical transmembrane domains in the N-terminal part and a long hydrophilic cytoplasmic tail in the C-terminal part. The expression pattern of this gene was investigated upon 250 mM NaCl treatment after 6 h and 1, 3, 8 and 17 days time courses. Expression of AlSOS1 greatly increased in leaves after 6 h. In node and internode tissues the transcript levels of AlSOS1 peaked at 24 h after salt treatment and then gradually decreased within 3 and 8 days and finally after 17 days reached to a steady-state in which the mRNA content was similar to that of control plants. The transcript abundance of this gene in roots slightly increased upon salt treatment and after 3 days reached to its maximum levels and this expression continued until 8 days and then decreased to reach a new steady-state in which the mRNA content was about 2-fold that of control plants.