Inhibitory effects of hypo-osmotic stress on extracellular carbonic anhydrase and photosynthetic efficiency of green alga Dunaliella salina possibly through reactive oxygen species formation

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• 作者：Wenhua Liu ; ^{whliu@stu.edu.cn} ; Yao Ming ; Ping Li ; Zhongwen Huang
• 关键词：Dunaliella salina ; Hypo-osmotic stress ; Photosynthetic efficiency ; Carbonic anhydrase ; Reactive oxygen species
• 刊名：Plant Physiology and Biochemistry
• 出版年：2012
• 期刊代码：87_09819428
• 类别：abs
• 出版时间：May, 2012
• 卷：54
• 期：Complete
• 页码：43-48
• 文件大小：462 K

摘要

In this study, Dunaliella salina (D.聽salina) maintained in 30鈥?salinity for more than two years was exposed to the salinities of 5鈥? 10鈥? 20鈥? 30鈥?(control) in order to investigate oxidative burst and it's possible connection with extracellular carbonic anhydrase (CA) under hypo-osmotic stress (low salinity). The results indicated that intracellular ROS contents increased significantly when cells were exposed to salinity of 5 and 10鈥? and the increase also occurred at 20鈥?salinity. The activity of extracellular CA and its gene (P60) expression decreased significantly when cells were exposed to salinity of 5-20鈥? Data from H₂O₂ treatments hinted that ROS production was possibly one of the factors affecting CA, including enzyme activity and gene expression levels. Significant inhibition of effective quantum efficiency of PSII and photosynthetic oxygen evolution rate were observed with the increase of ROS production and decline of CA activities. Taken together, hypo-osmotic stresses could induce ROS production in D.聽salina, and CA enzyme activities and expression levels were consequently inhibited. As a result, algal photosynthesis and oxygen evolution were inhibited.