Abstract：Plants increase their tolerance through accumulation of polyamines under salt stress. S-adenosylmethionine synthetase (SAMS) is an important rate-limiting enzyme involved in the biosynthesis polyamines. In this study, HvSAMS2 gene was isolated from farmhouse two-row barley (Hordeum vulgare), and analyzed for bioinformatics, tissue expression specificity and abiotic stress responses, subcellular localization and salt tolerance in Saccharomyces cerevisiae. The full-length cDNA sequence of HvSAMS2 was 1 297 bp without introns, which contained a 1 185 bp ORF that encoded 394 predicted amino acids, with a molecular weight of 42.83 kD and a hypothetical protein isoelectric point of 5.58. Multiple alignment analysis based on the amino acids indicated that HvSAMS2 was highly conserved to SAMS proteins from different species,and had the highest similarity of 93.06% to Aegilops tauschii SAMS2. Subcellular localization revealed that HvSAMS2 was located in the nucleus and cell membrane with a higher level in the nucleus. The qRT-PCR analysis results in different tissues indicated that HvSAMS2 was preferentially accumulated in root, and then leaves, following by stem. Furthermore, HvSAMS2 expression level was significantly enhanced upon drought, low temperature, salt, and methyl jasmonate (MeJA) treatment. Complete gene of HvSAMS2 was inserted into expression vector pYES2 and transformed into Saccharomyces cerevisiae INVSc1 for heterologous expression, and the expressing HvSAMS2 improved the salt tolerance of the engineered strain under salt stress. In summary, HvSAMS2 might play an important role in responding to abiotic stresses, and this study could provide basic data for further study on the molecular mechanism of salt resistance of SAMS genes.
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