Changes in Growth, Carbon and Nitrogen Enzyme Activity and mRNA Accumulation in the Halophilic Microalga Dunaliella viridis in Response to NaCl Stress  

作　　者：WANG Dongmei WANG Weiwei XU Nianjun SUN Xue WANG Dongmei;WANG Weiwei;XU Nianjun;SUN Xue(Key Laboratory of Applied Marine Biotechnology of Ministry of Education, School of Marine Sciences,Ningbo University, Ningbo 315211, P. R. China)

机构地区：[1]Key Laboratory of Applied Marine Biotechnology of Ministry of Education, School of Marine Sciences,Ningbo University, Ningbo 315211, P. R. China

出　　处：《Journal of Ocean University of China》2016年第6期1094-1100,共7页中国海洋大学学报（英文版）

基　　金：funded by the Project of Science and Technology Innovation Team of Zhejiang Province (2010R50025-25);sponsored by the K. C. Wong Magna Fund

摘　　要：Abstract Many species of microalga Dunaliella exhibit a remarkable tolerance to salinity and are therefore ideal for probing the effects of salinity. In this work, we assessed the effects of NaC1 stress on the growth, activity and mRNA level of carbon and nitrogen metabolism enzymes of D. viridis. The alga could grow over a salinity range of 0.44 mol L-t to 3.00 mol L-1 NaCI, but the most rapid growth was observed at 1.00molL-1NaC1, followed by 2.00 molL-l NaC1. Paralleling these growth patterns, the highest initial and total Rubisco activities were detected in the presence of 1.00molL-t NaC1, decreasing to 37.33% and 26.39% of those values, re- spectively, in the presence of 3.00 mol L-1 NaC1, respectively. However, the highest extracellular carbonic anhydrase （CA） activity was measured in the presence of 2.00molL-1 NaC1, followed by 1.00molL-1NaC1. Different from the two carbon enzymes, nitrate reductase （NR） activity showed a slight change under different NaC1 concentrations. At the transcriptional level, the mRNAs of Rubisco large subunit （rbcL）, and small subunit （rbcS）, attained their highest abundances in the presence of 1.00 and 2.00molL-1 NaC1, respectively. The CA mRNA accumulation was induced from 0.44molL ~ to 3.00molL-1 NaC1, but the NR mRNA showed the decreasing tendency with the increasing salinity. In conclusion, the growth and carbon fixation enzyme of Rubisco displayed similar tendency in response to NaC1 stress, CA was proved be salt-inducible within a certain salinity range and NR showed the least effect by NaC1 in D. viridis.Many species of microalga Dunaliella exhibit a remarkable tolerance to salinity and are therefore ideal for probing the effects of salinity. In this work, we assessed the effects of NaCl stress on the growth, activity and m RNA level of carbon and nitrogen metabolism enzymes of D. viridis. The alga could grow over a salinity range of 0.44 mol L^(-1) to 3.00 mol L^(-1) NaCl, but the most rapid growth was observed at 1.00 mol L^(-1) NaCl, followed by 2.00 mol L^(-1) NaCl. Paralleling these growth patterns, the highest initial and total Rubisco activities were detected in the presence of 1.00 mol L^(-1) NaCl, decreasing to 37.33% and 26.39% of those values, respectively, in the presence of 3.00 mol L^(-1) Na Cl, respectively. However, the highest extracellular carbonic anhydrase(CA) activity was measured in the presence of 2.00 mol L^(-1) NaCl, followed by 1.00 mol L^(-1) NaCl. Different from the two carbon enzymes, nitrate reductase(NR) activity showed a slight change under different NaCl concentrations. At the transcriptional level, the m RNAs of Rubisco large subunit(rbcL), and small subunit(rbc S), attained their highest abundances in the presence of 1.00 and 2.00 mol L^(-1)NaCl, respectively. The CA mRNA accumulation was induced from 0.44 mol L^(-1) to 3.00 mol L^(-1) NaCl, but the NR m RNA showed the decreasing tendency with the increasing salinity. In conclusion, the growth and carbon fixation enzyme of Rubisco displayed similar tendency in response to NaCl stress, CA was proved be salt-inducible within a certain salinity range and NR showed the least effect by NaCl in D. viridis.

关 键 词：Dunaliella viridis NaC1 RUBISCO carbonic anhydrase nitrate reductase 

分 类 号：Q945.78[生物学—植物学]