Arabidopsis tic62 trol Mutant Lacking Thylakoid- Bound Ferredoxin-NADP＋ Oxidoreductase Shows Distinct Metabolic Phenotype  

作　　者：Minna Lintala Natalie Schuck Ina Thormaihlen Andreas Jungfer Katrin L. Weber Andreas P.M. Weber Peter Geigenberger Juirgen Soil Bettina Bolter Paula Mulo 

机构地区：[1]Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland [2]Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universitat Munchen, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany [3]Department of Biology I, Botany, Ludwig-Maximilians-Universitat Munchen, Groβhaderner Strasse 2-4, D-82152 Planegg-Martinsried, Germany [4]Department of Biology I, Plant Metabolism Group, Ludwig-Maximilians-Universitat Munchen, Groβhaderner Strasse 2-4, D-82152 Planegg-Martinsried Germany [5]Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Universitatsstrasse 1, D-40225 Dusseldorf, Germany

出　　处：《Molecular Plant》2014年第1期45-57,共13页分子植物（英文版）

摘　　要：Ferredoxin-NADP＋ oxidoreductase （FNR）, functioning in the last step of the photosynthetic electron transfer chain, exists both as a soluble protein in the chloroplast stroma and tightly attached to chloroplast membranes. Surface plasmon resonance assays showed that the two FNR isoforms, LFNR1 and LFNR2, are bound to the thylakoid membrane via the C-terminal domains of Tic62 and TROL proteins in a pH-dependent manner. The tic62 trol double mutants contained a reduced level of FNR, exclusively found in the soluble stroma. Although the mutant plants showed no visual phenotype or defects in the function of photosystems under any conditions studied, a low ratio of NADPH/NADP~ was detected. Since the CO2 fixation capacity did not differ between the tic62 trol plants and wild-type, it seems that the plants are able to funnel reducing power to most crucial reactions to ensure survival and fitness of the plants. However, the activity of malate dehydrogenase was down-regulated in the mutant plants. Apparently, the plastid metabolism is able to cope with substantial changes in directing the electrons from the light reactions to stromal metabolism and thus only few differences are visible in steady-state metabolite pool sizes of the tic62 trol plants.Ferredoxin-NADP＋ oxidoreductase （FNR）, functioning in the last step of the photosynthetic electron transfer chain, exists both as a soluble protein in the chloroplast stroma and tightly attached to chloroplast membranes. Surface plasmon resonance assays showed that the two FNR isoforms, LFNR1 and LFNR2, are bound to the thylakoid membrane via the C-terminal domains of Tic62 and TROL proteins in a pH-dependent manner. The tic62 trol double mutants contained a reduced level of FNR, exclusively found in the soluble stroma. Although the mutant plants showed no visual phenotype or defects in the function of photosystems under any conditions studied, a low ratio of NADPH/NADP~ was detected. Since the CO2 fixation capacity did not differ between the tic62 trol plants and wild-type, it seems that the plants are able to funnel reducing power to most crucial reactions to ensure survival and fitness of the plants. However, the activity of malate dehydrogenase was down-regulated in the mutant plants. Apparently, the plastid metabolism is able to cope with substantial changes in directing the electrons from the light reactions to stromal metabolism and thus only few differences are visible in steady-state metabolite pool sizes of the tic62 trol plants.

关 键 词：carbon assimilation ferredoxin-NADP＋ oxidoreductase photosynthesis CHLOROPLAST stromal metabolism Tic62 TROL. 

分 类 号：Q946.1[生物学—植物学] Q554