Isolation and characterization of plasma membrane Na7H+ antiporter (SOS1) gene during salinity stress in kallar grass {Leptochloa fusca)

Background: Leptochloa fusca is a halophyte plant which is highly tolerant to saline and sodic soils and water. Moreover, L fusca is an attractive model plant to study the mechanism of salt tolerance mainly due to its characteristics as a typical euhalophyte, having both accumulating and excreting salt properties. Soil salinity adversely affects plant growth, development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1) gene encodes a plasma membrane NaVH+ antiporter that plays an important role in imparting salt stress tolerance of plants. Material and Methods: Using conserved sequences of S O S 1 , the coding sequence of plasma membrane NaVH+ antiporter (SOS1) in kallar grass was partially isolated and its expression profile during salinity stress was investigated. Results: The aa (amino acid) sequence of the isolated region of /./SOS1 possesses the maximum identity up to 96% of its orthologue in Distichlis spicata. The results of semi-quantitative RT-PCR revealed that salinization was affected SOS1 transcript level positively. The expression of i./50S1 in leaves of kallar grass progressively increased under all salinity levels compared to control. Conclusions: The results suggest that i./SOS1 may play an essential role in the salt tolerance of L fusca and may be useful for improving salt tolerance in other crop species.