Non-redundant Contribution of the Plastidial FAD8 ω-3 Desatumse to Glycerolipid Unsatumtion at Different Temperatures in Arabidopsis  

作　　者：Angela Roman Maria L. Hernandez Angel Soria-Garcia Sara Lopez-Gomollon Beatriz Lagunas Rafael Picorel Jose Manuel Martinez-Rivas Miguel Alfonso 

机构地区：[1]Estacion Experimental de Aula Dei (EEAD-CSIC), Avda. Montanana 1005, 50059 Zaragoza, Spain [2]Instituto de la Grasa (IG-CSIC), Campus Universidad Pablo de Olavide, Building 46, Ctra. Utrera kin, 1, 41013 Seville, Spain

出　　处：《Molecular Plant》2015年第11期1599-1611,共13页分子植物（英文版）

摘　　要：Plastidial ω-3 desaturase FAD7 is a major contributor to trienoic fatty acid biosynthesis in the leaves of Arabidopsis plants. However, the precise contribution of the other plastidial ω-3 desaturase, FAD8, is poorly understood. Fatty acid and lipid analysis of several ω-3 desaturase mutants, including two insertion lines of AtFAD7 and AtFAD8, showed that FAD8 partially compensated the disruption of the AtFAD7 gene at 22℃, indicating that FAD8 was active at this growth temperature, contrasting to previous observations that circumscribed the FAD8 activity at low temperatures. Our data revealed that FAD8 had a higher selectivity for 18：2 acyl-lipid substrates and a higher preference for lipids other than galactolipids, particularly phosphatidylglycerol, at any of the temperatures studied. Differences in the mechanism controlling AtFAD7 and AtFAD8 gene expression at different temperatures were also detected. Confocal microscopy and biochemical analysis of FAD8-YFP over-expressing lines confirmed the chloroplast envelope localization of FAD8. Co-localization experiments suggested that FAD8 and FAD7 might be located in close vicinity in the envelope membrane. FAD8-YFP over-expressing lines showed a specific increase in 18：3 fatty acids at 22℃. Together, these results indicate that the function of both plastidial ω-3 desaturases is coordinated in a non-redundant manner.Plastidial ω-3 desaturase FAD7 is a major contributor to trienoic fatty acid biosynthesis in the leaves of Arabidopsis plants. However, the precise contribution of the other plastidial ω-3 desaturase, FAD8, is poorly understood. Fatty acid and lipid analysis of several ω-3 desaturase mutants, including two insertion lines of AtFAD7 and AtFAD8, showed that FAD8 partially compensated the disruption of the AtFAD7 gene at 22℃, indicating that FAD8 was active at this growth temperature, contrasting to previous observations that circumscribed the FAD8 activity at low temperatures. Our data revealed that FAD8 had a higher selectivity for 18：2 acyl-lipid substrates and a higher preference for lipids other than galactolipids, particularly phosphatidylglycerol, at any of the temperatures studied. Differences in the mechanism controlling AtFAD7 and AtFAD8 gene expression at different temperatures were also detected. Confocal microscopy and biochemical analysis of FAD8-YFP over-expressing lines confirmed the chloroplast envelope localization of FAD8. Co-localization experiments suggested that FAD8 and FAD7 might be located in close vicinity in the envelope membrane. FAD8-YFP over-expressing lines showed a specific increase in 18：3 fatty acids at 22℃. Together, these results indicate that the function of both plastidial ω-3 desaturases is coordinated in a non-redundant manner.

关 键 词：Arabidopsis thaliana GLYCEROLIPID fatty acid FAD7 FAD8 PLASTID 

分 类 号：Q943[生物学—植物学] TN304.2[电子电信—物理电子学]