A novel salt-induced gene from sheepgrass, LcSAIN2, enhances salt tolerance in transgenic Arabidopsis

Salt stress affects plant growth and development, and limits the productivity of crops. Sheepgrass can grow well under various environmental and soil conditions and is a good wild resource in Triticeae. Using 454 high throughout sequencing technique, a large number of salt stress responsive genes have been picked out from sheepgrass. In this study, a novel salt-induced gene and its promoter were cloned and the gene was designated as LcSAIN2 (Leymus chinensis salt-induced 2). Bioinformatics analysis predicted that LcSAIN2 has one transmembrane helix and is localized in nucleus. Experiments of subcellular localization in tobacco leaf cells also indicated that it was mainly localized in nucleus. Several stress responsive elements were found in the promoter region of the LcSAIN2 gene. The expression analysis confirmed that LcSAIN2 was induced by salinity, PEG, ABA, and cold stresses, especially by high salinity. Overexpression of LcSAIN2 in Arabidopsis enhanced salt tolerance of transgenic plants by accumulating osmolytes, such as soluble sugars and free proline, and improving the expression levels of some stress-responsive transcription factors and key genes. Our results suggest that LcSAIN2 might play an important positive modulation role in salt stress tolerance and be a candidate gene utilized for enhancing stress tolerance in wheat and other crops.