Identification and characterization of mRNA transcripts differentially expressed in response to high salinity by means of differential display in the mangrove, Bruguiera gymnorrhiza

Abstract In this study we applied the differential display method to transcripts extracted from leaves of Bruguiera gymnorrhiza treated with 500 mM NaCl for 0, 6 h, 3 and 28 days to identify genes that are differentially expressed in response to salt stress. The expression of twelve transcripts, whose corresponding cDNA fragments differentially appeared on differential display, was then analyzed by northern hybridization. Nine of them were affirmed to be up-regulated or induced by salt treatment. By screening a cDNA library, we have cloned five full-length cDNAs and identified putative protein products for three of them by homology with known protein. The RNA transcript encoding fructose-6-phosphate, 2-kinase/fructose-2,6-bisphophatase increased at 6 h following salt treatment. Transcripts encoding dihydrolipoamide dehydrogenase and lipoic acid synthase distinctly increased from 1 to 3 days after salt treatment regardless of light condition. The relationship between the expression pattern of these RNA transcripts and the function of their respective encoding proteins in response to salt stress is discussed.