in English
Distribution of reducing power in plastid metabolism


Paula Mulo, Ph.D.
Assistant Professor
email: paula.mulo [at]


Paula Mulo, Assistant Professor, Project Leader 
Magda Grabsztunowicz, Postdoctoral Researcher
Minna Koskela, M.Sc., Ph.D. student


The chloroplasts of higher plants perform oxygenic photosynthesis resulting in the transfer of light energy into chemical form, which is the basis of heterotrophic life on Earth. Photosynthesis may be dived into two sets of reactions: light reactions taking place in the thylakoid membranes, and carbon fixation reactions in soluble stroma. To ensure immaculate primary production under a wide spectrum of environmental conditions, the structure and function of photosynthetic machinery must be extremely dynamic. The molecular mechanisms behind these dynamic changes remain largely uncharacterised, although detailed knowledge of these reactions is of utmost importance for understanding the adaptation on organism level


Ferredoxin-NADP+-oxidoreductase (FNR) is a FAD-containg enzyme found both in the chloroplasts and non-photosynthetic plastids of higher plants. In chloroplasts, FNR has a well-defined role in linear electron flow, and in the root plastids, FNR is needed for nitrogen metabolism. In Arabidopsis thaliana, FNR is encoded by a gene family: At1g30510 and At4g05390 encode the root isozyme of FNR and At5g66190 and At1g20020 encode the leaf/chloroplast isozyme, which share a high degree of homology. Since FNR is a crucial determinant for the acclimation of the photosynthetic machinery, we have recently focused on resolving the specific physiological roles of the two distinct chloroplast-targeted FNR isoforms using the Arabidopsis fnr knock-out mutants (Lintala et al. 2007; 2009; 2012). We have also resolved the binding partner and the physiological significance of FNR shuttling within the chloroplast (Benz et al. 2009; 2010; Lintala et al.2014), and established differential drought stress -induced expression of various genes encoding potential components (including FNR isoforms) of cyclic electron transfer (Lehtimäki et al. 2010). Moreover, we have focused on the effects of post-translational modifications on the function of FNR (Lehtimäki et al. 2014).
The ultimate aim of our project is to resolve how the reducing power produced by the photosystems is distributed towards various stromal reactions.
Our aim is to resolve which alternative electron transfer routes are induced upon specific stress conditions, to characterize the role of FNR in these reactions, and to identify novel molecular components involved in the alternative electron transfer routes in the chloroplasts of higher plants.


Oxygenic photosynthesis, producing carbohydrates and oxygen, is the basis of heterotrophic life on Earth. The success to apply photosynthesis in production of sustainable and carbon neutral energy as well as in production of maximal yields for food supplies depends on the thorough understanding of photosynthetic mechanisms.



Füßl M, Lassowskat I, Née G, Koskela MM, Brünje A, Tilak P, Giese J, Leister D, Mulo P, Schwarzer D and Finkemeier I (2018) Beyond histones: New substrate proteins of lysine deacetylases in Arabidopsis nuclei. Front. Plant Sci., 10 April
Koskela MM, Dahlström KM, Goñi G, Lehtimäki N, Nurmi M, Velazquez-Campoy A, Hanke G, Bölter B, Salminen TA, Medina M, Mulo P. 2017: Arabidopsis FNRL protein is an NADPH-dependent chloroplast oxidoreductase resembling bacterial ferredoxin-NADP+ reductases. Physiologia Plantarum, in press [A1]  (Epub ahead of print)
Mulo, P. and Medina, M. (2017) Interaction and electron transfer between ferredoxin-NADP+ oxidoreductase and its partners: structural, functional and physiological implications. Photosynthesis Research, in press. (Epub 2017 Mar 30).
Grabsztunowicz, M., Koskela, M.M. and Mulo P. 2017: Post-translational modifications in regulation of chloroplast function: recent advances. Frontiers in Plant Science 8, 240.  Free article (eCollection 2017)
Yang, C.; Hu, H.; Ren, H.; Kong, Y.; Lin, H.; Guo, J.; Wang, L.; He, Y.; Ding, X.; Grabsztunowicz, M.; Mulo, P.; Chen, T.; Liu, Y.; Wu, Z.; Wu, YR.; Mao, C.; Wu,, P. & Mo, X. 2016:   LIGHT-INDUCED RICE1 regulates light-dependent attachment of LEAF-TYPE FERREDOXIN-NADP+ OXIDOREDUCTASE to the thylakoid membrane in rice and Arabidopsis. - PLANT CELL 28(3): 712-728.   (Epub 2016 Mar 3).
Allahverdiyeva, Y.; Battchikova, N.; Brosché*, M.; Fujii, H.; Kangasjärvi, S.; Mulo, P.; Mähönen*, AP.; Nieminen*, K.; Overmyer*, K.; Salojärvi* J. & Wrzaczek*, M. 2015:  Integration of photosynthesis, development and stress as an opportunity for plant biology. - NEW PHYTOLOGIST 208(3): 647-655.  Free article    (Epub 2015 Jul 14).
Urbischek*, M.; Nick von Braun*, S.; Brylok*, T.; Gügel*, IL.; Richter*, A.; Koskela, M.; Grimm*, B.; Mulo, P.; Bölter*, B.; Soll*, J.; Ankele*, E. & Schwenkert*, S. 2015:  The extreme Albino3 (Alb3) C terminus is required for Alb3 stability and function in Arabidopsis thaliana. - PLANTA 242(3): 733-746.   (Epub 2015 Jun 24).
Lehtimäki, N.; Koskela, MM. & Mulo, P. 2015:  Post-translational modifications of chloroplast proteins: An emerging field. - PLANT PHYSIOLOGY 168(3): 768-775..   (Epub 2015 Apr 24).
Lehtimäki, N.; Koskela, MM.; Dahlström*, KM.; Pakula, E.; Lintala, M.; Scholz*, M.; Hippler*, M.; Hanke*, GT.; Rokka, A.; Battchikova, N.; Salminen*; TA. &  Mulo P. 2014:  Posttranslational modifications of FERREDOXIN-NADP+ OXIDOREDUCTASE in Arabidopsis chloroplasts. - PLANT PHYSIOLOGY 166(4): 1764-1776.    Free article   (Epub 2014 Oct 9)
Ghotbi-Ravandi*, AA.; Shahbazi*, M.; Shariati*, M. & Mulo, P. 2014:  Effects of mild and severe drought stress on photosynthetic efficiency in tolerant and susceptible barley (Hordeum vulgare L.) genotypes. - JOURNAL OF AGRONOMY AND CROP SCIENCE 200(6): 403-415.   (Epub 2014 Apr 29).
Lintala, M.; Schuck*, N.; Thormählen*, I.; Jungfer*, A.; Weber*, KL.; Weber*, AP.; Geigenberger*, P.; Soll*, J.; Bölter*, B. & Mulo, P. 2014:  Arabidopsis tic62 trol mutant lacking thylakoid bound ferredoxin-NADP+ oxidoreductase shows distinct metabolic phenotype. - MOLECULAR PLANT 7(1): 45-57.   (Epub 2013 Dec 2).
Carmel, D.; Dahlström*, KM.; Holmström, M.; Allahverdiyeva, Y.; Battchikova, N.; Aro, EM.; Salminen*, TA. & Mulo, P. 2013:  Structural model, physiology and regulation of Slr0006 in Synechocystis PCC 6803. - ARCHIVES OF MICROBIOLOGY 195(10-11): 727-736.
Hanke*, G. & Mulo, P. 2013:  Plant type ferredoxins and ferredoxin-dependent metabolism. - PLANT, CELL & ENVIRONMENT 36(6): 1071-1084.
Shunmugam, S.; Hinttala*, R.; Lehtimäki, N.; Miettinen*, M.; Uusimaa*, J.; Majamaa*, K.; Sivonen*, K.; Aro, EM. & Mulo, P. 2013:  Nodularia spumigena extract induces upregulation of mitochondrial respiratory chain complexes in spinach (Spinacia oleracea L.). - ACTA PHYSIOLOGIAE PLANTARUM 35(3): 969-974.
Lintala, M.; Lehtimäki, N.; Benz*, JP; Jungfer*, A.; Soll*, J.; Aro, EM.; Bölter*, B. & Mulo, P. 2012:  Depletion of leaf-type ferredoxin-NADP+ oxidoreductase results in permanent induction of photoprotective mechanisms in Arabidopsis chloroplasts. - THE PLANT JOURNAL 70(5): 809-817.
Hebbelmann*, I.; Selinski*, J.; Wehmeyer*, C.; Goss*, T.; Voss*, I.; Mulo, P.; Kangasjärvi, S.; Aro, EM.; Oelze*, ML.; Dietz*, KJ.; Nunes-Nesi*, A.; Do*, PT.; Fernie*, AR.; Talla*, SK.; Raghavendra*, AS.; Linke*, V. & Scheibe*, R. 2012:  Multiple strategies to prevent oxidative stress in Arabidopsis plants lacking the malate valve enzyme NADP-malate dehydrogenase. -JOURNAL OF EXPERIMENTAL BOTANY 63(3): 1445-1459.   Free article
Mulo, P.; Sakurai, I. & Aro, EM. (2012)  Strategies for psbA gene expression in cyanobacteria, green algae and higher plants: From transcription to PSII repair. - BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1817(1): 247-257.
Lehtimäki, N., Shunmugam, S., Jokela, J., Wahlsten, M., Carmel, D., Keränen, M., Sivonen, K, Allahverdiyeva, Y., Aro, E.-M., Mulo, P.(2011) Nodularin uptake and induction of oxidative stress in spinach (Spinachia oleracea). Journal of Plant Physiology, 168, 594-600.
Trotta, A., Wrzaczek, M., Scharte, J., Tikkanen, M., Konert, G., Rahikainen, M., Holmström, M., Hiltunen H-M., Rips, S., Sipari, N., Mulo, P., Weis, E., von Schaewen, A., Aro, E-M. and Kangasjärvi, S. (2011) Regulatory subunit B’γ of protein phosphatase 2A prevents unnecessary defense reactions under low light in Arabidopsis thaliana. Plant Physiology 156, 1464-80.
Carmel, D., Battchikova, N., Mulo, P., Aro, E.-M. (2011) Membrane attachment of Slr0006 in Synechocystis sp. PCC 6803 is determined by divalent ions. Photosynthesis Research, in press.
Mulo, P. (2011) Chloroplast -targeted ferredoxin-NADP+ oxidoreductase (FNR): Structure, function and location. - BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1807(8): 927-934..
*Benz; JP., Lintala, M., *Soll; J., Mulo; P., *Boelter, B. (2010)  New concept for ferredoxin-NADP(H)oxidoreductase binding to plant thylakoids. - TRENDS IN PLANT SCIENCE 15(11): 608-613.
Brandt, AM., Raksajit, W., Yodsang, P., Mulo, P., Incharoensakdi, A., Salminen, TA., Mäenpää, P. (2010)  Characterization of the substrate-binding PotD subunit in Synechocystis sp. strain PCC 6803. - ARCHIVES OF MICROBIOLOGY 192(10): 791-801.
Lehtimäki, N., Lintala, M., Allahverdiyeva, Y., Aro, E.-M., Mulo, P. (2010) Drought stress -induced upregulation of components involved in ferredoxin-dependent cyclic electron transfer. J. Plant Physiol. 167:1018-22.
Benz, J.P., Stengel, A., Lintala, M., Lee, Y.-H., Weber, A., Philippar, K., Gügel, L.L., Kaieda, S., Ikegami, T., Mulo, P., Soll, J. and Bölter, B. (2009) Arabidopsis Tic62 and ferredoxin-NADP(H) oxidoreductase form light-regulated complexes that are integrated into the chloroplast redox poise. Plant Cell 21, 3965-3983.
Mulo, P., Sicora, C. and Aro, E.-M. (2009) Cyanobacterial psbA gene family ?optimization of oxygenic photosynthesis. Cellular and Molecular Life Sciences 66, 3697-3710.
Lintala, M., Allahverdiyeva, Y., Lehtimäki, N., Kangasjärvi, S., Keränen, M., Rintamäki, E., Aro, E-M. and Mulo, P. (2009) Comparative analysis of leaf-type ferredoxin-NADP+-oxidoreductase isoforms in Arabidopsis thaliana. The Plant Journal 57, 1103-1115.
Mulo, P., Sirpiö, S., Suorsa, M. and Aro, E-M. (2008) Auxiliary proteins involved in the assembly and sustenance of Photosystem II. Photosynthesis Research 98, 489-501.
Lintala M., Allahverdiyeva, Y., Kidron, H., Piippo, M., Battchikova, N., Suorsa, M., Rintamäki, E., Salminen, T., Aro, E-M. and Mulo, P. (2007)  Structural and functional characterization of ferredoxin-NADP+-oxidoreductase using knock-out mutants of Arabidopsis. The Plant Journal 49, 1041-1052.
Tikkanen, M., Piippo, M., Suorsa, M., Sirpiö, S., Mulo, P., Allahverdiyeva, Y., Aro, E-M. (2006) State transitions revisited-a buffering system for dynamic low light acclimation of Arabidopsis. Plant Molecular Biology 62, 779-793.