Enhanced photosynthesis and redox energy production contribute to salinity tolerance in Dunaliella as revealed by homology-based proteomics
Enhanced photosynthesis and redox energy production contribute to salinity tolerance in Dunaliella as revealed by homology-based proteomics
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DOI：
10.1104/pp.104.039438
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发表时间：
2004-09-01
期刊：
影响因子：
7.4
通讯作者：
Katz, A
中科院分区：
文献类型：
--
作者：
Liska, AJ;Shevchenko, A;Katz, A
盐度是植物增殖的主要限制因素，并抑制光合作用等中心代谢活动。耐盐绿色藻类杜氏藻能够适应高盐环境，被认为是耐盐光合生物的模式。为了阐明盐耐受性的分子基础，采用蛋白质组学方法鉴定了杜氏藻盐诱导蛋白。从不同亚细胞组分的二维凝胶分离中选择76个盐诱导蛋白，并通过质谱（MS）进行分析。应用纳米电喷雾质谱，结合序列相似性数据库搜索算法，MS BLAST和MultiTag，能够识别80%的盐诱导蛋白质。盐胁迫上调了卡尔文循环、淀粉动员和氧化还原能量产生中的关键酶;蛋白质生物合成和降解中的调节因子;以及细菌Na（+）-氧化还原转运蛋白的同系物。结果表明，盐藻对高盐胁迫的反应是通过增强光合作用中的CO2同化作用，并将碳源和能源转移到渗透物质甘油的合成上。盐藻在高盐环境下提高光合作用活性的能力是显著的，因为在大多数植物和蓝藻中，盐胁迫抑制光合作用。结果证明了MS BLAST搜索在基因组未知的生物体中鉴定蛋白质的能力，并为解剖藻类和高等植物耐盐性的分子机制铺平了道路。
Salinity is a major limiting factor for the proliferation of plants and inhibits central metabolic activities such as photosynthesis. The halotolerant green alga Dunaliella can adapt to hypersaline environments and is considered a model photosynthetic organism for salinity tolerance. To clarify the molecular basis for salinity tolerance, a proteomic approach has been applied for identification of salt-induced proteins in Dunaliella. Seventy-six salt-induced proteins were selected from two-dimensional gel separations of different subcellular fractions and analyzed by mass spectrometry (MS). Application of nanoelectrospray mass spectrometry, combined with sequence-similarity database-searching algorithms, MS BLAST and MultiTag, enabled identification of 80% of the salt-induced proteins. Salinity stress up-regulated key enzymes in the Calvin cycle, starch mobilization, and redox energy production; regulatory factors in protein biosynthesis and degradation; and a homolog of a bacterial Na(+)-redox transporters. The results indicate that Dunaliella responds to high salinity by enhancement of photosynthetic CO(2) assimilation and by diversion of carbon and energy resources for synthesis of glycerol, the osmotic element in Dunaliella. The ability of Dunaliella to enhance photosynthetic activity at high salinity is remarkable because, in most plants and cyanobacteria, salt stress inhibits photosynthesis. The results demonstrated the power of MS BLAST searches for the identification of proteins in organisms whose genomes are not known and paved the way for dissecting molecular mechanisms of salinity tolerance in algae and higher plants.