Cloning and Characterization of a Novel S-Adenosyl-L-Methionine Synthase Gene in Tobacco

Differential display method was used to identify novel genes regulated by the ethylene generator,ethephon in tobacco plants.A full length cDNA of S-Adenosyl-L-Methionine synthase (SAMS2) which contains 1350 bp was isolated by this way combined with RACE technology.Sequence analysis revealed that this gene shared 90% similarity in gene sequence and 96% similarity in protein sequence with a known SAMS (SAMS1) gene though they have low homologous in the 5’ and 3’ uncoden region.RT-PCR analysis indicated that the expression of SAMS1 was induced by the treatment of high temperature but has no response to oxidative stress induced by methyl viologen (MV) and NaCl stress,while SAMS2 was up-regulated by all the three stress treatment.