Cloning And Transformation Analysis Of Dehydrin Gene Of Rhizophora Stylosa

Mangroves grow in estuarine or intertidal zone of tropical and subtropical area. Due to growth in marine environment with high-salt and long-term endurance of high osmotic pressure, mangroves have evolved a set of salt-tolerant mechanism, which differs from that of terrestrial plants or other aquatic plants.Mangroves are referred as true halophytes.Rhizophora stylosa is one species of mangrove and belongs to Rhizophoraceae, Rhizophora. Rhizophora stylosa is a good target to study mechanism of plant salt-tolerance. In order to clone salt-tolerant-related genes of Rhizophora stylosa, a cDNA library has been constructed. Furthermore, Rhizophora stylosa were grown in fresh water or in saline respectively, differentially expressed genes at its roots under two different growth conditions were analysed by macroarray, some salt-tolerant related ESTs (expression sequence tag) were identified.Full-length sequence of a EST was identified by RT-PCR and RACE technology (rapid amplification of cDNA ends). It contained a 146bp 5'-UTR (untranslation region), a 43-bp 3'-UTR and an open reading frame encoding a protein of 241 amino acid. The deduced protein showed typical domain of plant dehydrin proteins contained conserved S and K segments, belonged to SKn class of plant dehydrin and was termed as RsDHNl.RsDHNl shared 43-55% homology with the SKn dehydrins of other plant species. Semi-quantative RT-PCR analysis showed that salt treatment significantly upregulated the expression of RsDHNl.Finally, RsDHNl expression vector was constructed and successfully transformed it into tobacco (Nicotiana tabacum). Additionally, an expression vector containing another salt-tolerant related gene, germin like proteins (RsGLP), was also constructed and successfully transformed it into tobacco and rice (Oryza sativa). RsGLP-GFP fusion expression shows that the protein locates in cell wall. The trangenic plants would be investigated in the late study. These results provide a preliminary explore to identify the salt-tolerance-related genes from Rhizophora stylosa for understanding the mechanism of mangrove, which lays a good foundation for characterization of mangrove salt-related genes and breeding salt-tolerant crops.