The Role Of Ceriops Tagal Antioxidative Enzymes In Salt Tolerance

Differential responses to the environmental stresses at the level of transcription play a critical role in adaptation. Mangroves are woody plants that grow along tropical and subtropical coasts and form clumpy stands in intertidal zones. Although the anatomical and physiological features associated with their salt-tolerant lifestyles have been well characterized, little is known about the impact of transcriptional phenotypes on their adaptation to these saline environments. In this study, we attempted to use the microarray technique to uncover the connection between salt-induced time-course transcript profiling and the salinity-adaptation capability of C. tagal. We identified differentially expressed genes (DEGs) by comparing salt-shocked samples with unstressed controls.(1) The content of soluble protein and enzyme activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in the C. tagal roots treated by four concentrations (0,150mmol/L,300mmol/L、450mmol/L) of NaCl were studied in a greenhouse of Hainan University, Haikou, China. The results showed that the activity of all these antioxidative enzymes had a certain increase at the indicated salt concentrations, which indicated that cell plasma membrane of C. tagal roots had rather strong resistance to the injury of salt ion.(2) A series of microarray experiments to monitor the transcript profiles using young roots that were shocked with500mmol/L NaCl for0,1,9,24hours were utilized to characterize the effects of salt shock on C. tagal. High-salinity-induced Differentially Expressed Genes (DEGs) were identified and Functional Annotated. Among all these DEGs, two full length CDS (Mn-SOD�'�1Cu/Zn-SOD) were choosen as candidate gene for salt resistance.(3) The whole Mn-SOD and Cu/Zn-SOD DNA fragment were amplified by PCR, digested with restriction enzymes and cloned into pYES2vector. Sequencing was performed to identify the recombinant. pYES2-Mn SOD and pYES2-Cu/Zn SOD were transformed into yeast INVSc I.(4) When pYES2-Mn SOD and pYES2-Cu/Zn SOD plasmid was transformed into yeast, galactose instead of glucose was used to induce Mn-SOD and Cu/Zn-SOD expression. Western blot was performed to identify the quantity of the expressed Mn-SOD and Cu/Zn-SOD. Compared with the negative control group, both yeasts containing pYES2-MnSOD and pYES2-Cu/Zn SOD can express well. We concluded that a high effective yeast expression system for Mn-SOD and Cu/Zn-SOD were constructed successfully.(5) Different concentrations of salt were utilized to stress the Yeast strains of INVSc I(pYES2), INVSc I(pYES2-Mn SOD) and INVSc I(pYES2-Cu/Zn SOD), the results showed that the Yeast strains INVSc I(pYES2-Mn SOD) and INVSc I (pYES2-Cu/Zn SOD) were significantly more salt resistsnt than that of the INVSc I(pYES2). Which means that superoxide dismutase produced by the INVSc I (pYES2-Mn SOD) and INVSc I(pYES2-Cu/Zn SOD) coult protect the yeast cells against salt stress.