Ammopiptanthus mongolicus is the only evergreen broadleaf shrub endemic to the Alashan desert, northwest sandy area of China, which can survive at–30℃or an even lower temperature in winter. By cDNA-AFLP analysis, a cold induced gene AmGolS encoding galactinol synthase (GolS) was characterized and cloned from A. mongolicus. Except for cold up-regulation, AmGolS transcripts were induced by drought, high salinity stress and abscisic acid (ABA) revealed by Real-time PCR data. The presences of several binding sites in the promoter area of AmGolS implicated that AmGolS is likely to be regulated by some transcription factors associated with stress. AmGolS gene conferred cold tolerance to both transgenic Escherichia coli and Arabidopsis, possibly by catalyzing the first committed step in biosynthesis of the raffinose family oligosaccharides (RFOs). It is suggested that GolS may play an important osmotic protective role in cold acclimation.
|