Cyanobacterial monogalactosyldiacylglycerol-synthesis pathway is involved in normal unsaturation of galactolipids and low-temperature adaptation of Synechocystis sp. PCC 6803
Cyanobacterial monogalactosyldiacylglycerol-synthesis pathway is involved in normal unsaturation of galactolipids and low-temperature adaptation of Synechocystis sp. PCC 6803
复制标题
蓝藻单半乳糖二酰基甘油合成途径参与半乳糖脂的正常不饱和和集胞藻的低温适应。
DOI：
10.1016/j.bbalip.2013.12.007
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
et al.
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文献类型：
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作者：
Yuichi Yuzawa;et al.
我们使用集胞藻（Synechocystissp）表征了蓝藻单葡萄糖二酰基甘油的某些生理功能。 PCC 6803突变体，其中单葡糖基二酰基甘油合酶基因已被破坏，并且通过包含拟南芥单半乳糖基二酰基甘油合酶基因来补充其功能。通过使用这种方法，我们制备了第一个可行的蓝藻单葡糖基二酰基甘油缺陷突变体，并发现当拟南芥单半乳糖基二酰基甘油合酶充分提供单半乳糖基二酰基甘油时，在一组“正常生长条件”下，单葡糖基二酰基甘油对其生长和光合作用不是必需的。突变体具有健康的类囊体膜和正常的色素含量。突变体的膜脂组成与WT相似，只是在常温和低温下缺乏单葡萄糖二酰甘油并且磷脂酰甘油水平略有增加。然而，与WT相比，突变体中单半乳糖二酰甘油和双半乳糖二酰甘油中不饱和脂肪酸的比例降低。尽管在正常生长温度下突变体的生长与WT没有区别，但与WT相比，在低温下其生长明显迟缓。我们的数据表明，蓝藻单半乳糖二酰基甘油合成途径可能是半乳糖脂中脂肪酸足够不饱和水平所必需的，并影响低温敏感性。
We characterized certain physiological functions of cyanobacterial monoglucosyldiacylglycerol using aSynechocystissp. PCC 6803 mutant in which the gene for monoglucosyldiacylglycerol synthase had been disrupted and its function complemented by inclusion of anArabidopsismonogalactosyldiacylglycerol synthase gene. By using this method, we prepared the first viable monoglucosyldiacylglycerol-deficient mutant of cyanobacterium and found that monoglucosyldiacylglycerol is not essential for its growth and photosynthesis under a set of “normal growth conditions” when monogalactosyldiacylglycerol is adequately supplied by theArabidopsismonogalactosyldiacylglycerol synthase. The mutant had healthy thylakoid membranes and normal pigment content. The membrane lipid composition of the mutant was similar with that of WT except lack of monoglucosyldiacylglycerol and a slight increase in the level of phosphatidylglycerol at both normal and low temperatures. However, the ratio of unsaturated fatty acids in monogalactosyldiacylglycerol and digalactosyldiacylglycerol was reduced in the mutant compared with WT. Although the growth of the mutant was indistinguishable with that of WT at normal growth temperature, it was markedly retarded at low temperature compared with that of WT. Our data indicated the possibility that cyanobacterial monogalactosyldiacylglycerol-synthesis pathway might be required for the adequate unsaturation level of fatty acids in galactolipids and affect the low-temperature sensitivity.