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Cross-talk between light acclimation and defence reactions in plants

Contact information

Saijaliisa Kangasjärvi
e-mail: saijaliisa.kangasjarvi [at]


Saijaliisa Kangasjärvi, Dr, Docent, Senior Lecturer, Project Leader
Guido Durian,  Dr., Postdoctoral Researcher
Jesus Pascual, Dr., Postdoctoral Researcher
Moona Rahikainen, MSc, Doctoral Student
Sara Alegre Garcia, MSc, Doctoral Student
Zsofia Winter, MSc


Besides photosynthesis, chloroplasts perform essential signalling functions in light acclimation and various stress responses in plants. The final acclimation responses are, however, influenced by cross-talk with other components of the cellular signalling networks. The main objective of this project is to identify novel components in the cross-talk of chloroplast signaling using Arabidopsis thaliana as a tool.


We have taken a reverse genetic approach to identify novel components in the cross-talk of chloroplast signaling. Mutants deficient in protein phosphatase 2A (PP2A) subunits showed peculiar light-intensity-dependent phenotypes, and were therefore chosen for further analysis.
 A specific PP2A regulatory subunit B was identified as a cytoplasmic component in the cross-talk between light acclimation and disease resistance in Arabidopsis thaliana. Another highly similar mitochondrial PP2A subunit seems to have a distinct function in the regulation of cellular energy metabolism. Intriguingly, however, genetic analysis indicates that these two distinct PP2A regulatory B subunits are functionally interconnected with each other.
Currently, we are working on identification of the specific PP2A-B-dependent target processes of PP2A. A combination of yeast two-hybrid screening, affinity purification assays, proteomic approaches and phenotypic analysis of Arabidopsis mutants is expected to specify the mechanisms of PP2A function in plants.


It has become well-known that type 2 protein phosphatases carry out crucial signalling functions in the regulation of phosphorelay cascades in both animals and plants. Thus, analysis of PP2A and its signalling interactions in plants may provide novel insights into its functional role in mammalian systems as well. Furthermore, generation of stress-resistant crop plants or production of biopharmaceuticals in plants will become possible when a comprehensive view to defence mechanisms and developmental processes in plants has been achieved. Our work is part of this goal.

Recent publications

Rahikainen M, Alegre S, Trotta A, Pascual J, Kangasjärvi S. 2017. Trans-methylation reactions in plants: focus on the activated methyl cycle. Physiologia Plantarum, in press. [A2]  [Epub ahead of print]

Salojärvi J, Smolander OP, Nieminen K, Rajaraman S, Safronov O, Safdari P, Lamminmäki A, Immanen J, Lan T, Tanskanen J, Rastas P, Amiryousefi A, Jayaprakash B, Kammonen JI, Hagqvist R, Eswaran G, Ahonen VH, Serra JA, Asiegbu FO, de Dios Barajas-Lopez J, Blande D, Blokhina O, Blomster T, Broholm S, Brosché M, Cui F, Dardick C, Ehonen SE, Elomaa P, Escamez S, Fagerstedt KV, Fujii H, Gauthier A, Gollan PJ, Halimaa P, Heino PI, Himanen K, Hollender C, Kangasjärvi S, Kauppinen L, Kelleher CT, Kontunen-Soppela S, Koskinen JP, Kovalchuk A, Kärenlampi SO, Kärkönen AK, Lim KJ, Leppälä J, Macpherson L, Mikola J, Mouhu K, Mähönen AP, Niinemets Ü, Oksanen E, Overmyer K, Palva ET, Pazouki L, Pennanen V, Puhakainen T, Poczai P, Possen BJHM, Punkkinen M, Rahikainen MM, Rousi M, Ruonala R, van der Schoot C, Shapiguzov A, Sierla M, Sipilä TP, Sutela S, Teeri TH, Tervahauta AI, Vaattovaara A, Vahala J, Vetchinnikova L, Welling A, Wrzaczek M, Xu E, Paulin LG, Schulman AH, Lascoux M, Albert VA, Auvinen P, Helariutta Y, Kangasjärvi J. (2017) Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch. Nat Genet. 49(6): 904-912 [A1]
Jakobson, L.; Vaahtera, L.; Tõldsepp, K.; Nuhkat, M.; Wang, C.; Wang, YS.; Hõrak, H.; Valk, E.; Pechter, P.; Sindarovska, Y.; Tang, J.; Xiao, C.; Xu, Y.; Gerst Talas, U.; García-Sosa, AT.; Kangasjärvi, S.; Maran, U.; Remm, M.; Roelfsema, MR.; Hu, H.; Kangasjärvi, J.; Loog, M.; Schroeder, JI.; Kollist, H. & Brosché M. 2016:  Natural variation in Arabidopsis Cvi-0 accession reveals an important role of MPK12 in guard cell CO2 signaling. - PLOS BIOLOGY 14(12): e2000322   [A1]
Rahikainen, M.; Trotta, A.; Alegre, S.; Pascual, J.; Vuorinen, K.; Overmyer, K.; Moffatt, B.; Ravanel, S.; Glawischnig, E., &, Kangasjärvi, S. 2016:  PP2A-B'γ modulates foliar trans-methylation capacity and formation of 4-methoxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves. -THE PLANT JOURNAL 89(1): 112-127.  (Epub 2016 Sep 6).
Durian, G.; Rahikainen, M.; Alegre García, S.; Brosché*, M. & Kangasjärvi, S. 2016:  Protein Phosphatase 2A in the regulatory network underlying biotic stress resistance in plants. - FRONTIERS IN PLANT SCIENCE 7(812): 1-17.   Free article   (Epub 2016 Jun 10).
Rahikainen, M.; Pascual, J.; Alegre, S.; Durian, G: & Kangasjärvi, S. 2016:  PP2A phosphatase as a regulator of ROS signaling in plants. - ANTIOXIDANTS 5(1): 8 11 pp.   Free article   (Epub 2016 Mar 2).
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).
Konert, G.; Rahikainen, M.; Trotta, A.; Durian, G.; Salojärvi J, Khorobrykh S, Tyystjärvi E, Kangasjärvi S. 2015:  Subunits B'γ and B'ζ of Protein Phosphatase 2A regulate photo-oxidative stress responses and growth in Arabidopsis thaliana. - PLANT, CELL & ENVIRONMENT 38(12): 2641-2651).   (Epub 2015 May 27).
Konert, G.; Trotta, A.; Kouvonen*, P.; Rahikainen, M.; Durian, G.; Blokhina*, O.; Fagerstedt*, K.; Muth*, D.; Corthals*, GL. & Kangasjärvi S. 2014:  Protein phosphatase 2A (PP2A) regulatory subunit B'γ interacts with cytoplasmic ACONITASE 3 and modulates the abundance of AOX1A and AOX1D in Arabidopsis thaliana. - NEW PHYTOLOGIST 205(3): 1250-1263.   (Epub 2014 Oct 13).
Rasool*, B.; Karpinska*, B.; Konert, G.; Durian, G.; Denessiouk*, K.; Kangasjärvi, S. & Foyer, CH. 2014:  Effects of light and the regulatory B-subunit composition of protein phosphatase 2A on the susceptibility of Arabidopsis thaliana to aphid (Myzus persicae) infestation. - FRONTIERS IN PLANT SCIENCE 5(405): 1-11.   Free article   (Epub 2014 Aug 21).
Casanova-Sáez*, R.; Mateo-Bonmatí*, E.; Kangasjärvi, S.; Candela*, H. & Micol*,  JL. 2014:  Arabidopsis ANGULATA10 is required for thylakoid biogenesis and mesophyll development. - JOURNAL OF EXPERIMENTAL BOTANY 65(9): 2391-2404.  Free article  (Epub 2014 Mar 24).
Kangasjärvi, S. & Kangasjärvi*, J. 2014:  Towards understanding extracellular ROS sensory and signaling systems in plants. - ADVANCES IN BOTANY 2014, Article ID 538946: 1-10.  Free article   (Epub 2014 Jun 1). 
Kangasjärvi, S.; Tikkanen, M.; Durian, G. & Aro, EM. 2014:  Photosynthetic light reactions – An adjustable hub in basic production and plant immunity signaling. - PLANT PHYSIOLOGY AND BIOCHEMISTRY 81: 128-134.   (Epub 2013 Dec 14).
Li*, S.; Mhamdi*, A.; Trotta, A.; Kangasjärvi, S. & Noctor*, G. 2014:  The protein phosphatase subunit PP2A-B'γ is required to suppress day length-dependent pathogenesis responses triggered by intracellular oxidative stress. - NEW PHYTOLOGIST 202(1): 145-160.   (Epub 2013 Dec 2).
Trotta, A.; Rahikainen, M.; Konert, G.; Finazzi*, G. & Kangasjärvi, S. 2014:  Signalling crosstalk in light stress and immune reactions in plants. - PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B 369(1640): 20130235   (Epub 2014 Mar 3).
Heidari*, B.; Nemie-Feyissa*, D.; Kangasjärvi, S. & Lillo*, C. 2013:  Antagonistic regulation of flowering time through distinct regulatory subunits of protein phosphatase 2A. -  PLoS ONE 8(7): e67987.
Pérez-Pérez*, JM.; Esteve-Bruna*, D.; González-Bayón*, R.; Kangasjärvi, S.; Caldana*, C.; Hannah*, MA.; Willmitzer*, L.; Ponce*, MR. & Micol*, JL. 2013:  Functional redundancy and divergence within the Arabidopsis RETICULATA-RELATED gene family. - PLANT PHYSIOLOGY 162(2): 589-603.​1104/​pp.​113.​217323   Free article
Suorsa, M.; Grieco, M.; Järvi, S.; Gollan, PJ.; Kangasjärvi, S.; Tikkanen, M. & Aro, EM. 2013: PGR5 ensures photosynthetic control to safeguard photosystem I under fluctuating light conditions. -  PLANT SIGNALLING BEHAVIOR 8(1): 1-6.
Sierla*, M.; Rahikainen, M.; Salojärvi*, J.; Kangasjärvi*, J. & Kangasjärvi, S. 2013:  Apoplastic and chloroplastic redox signaling networks in plant stress responses. - ANTIOXIDANTS & REDOX SIGNALING 18(16): 2220-2239.
Grouneva, I.; Gollan, PJ.; Kangasjärvi, S.; Suorsa, M.; Tikkanen, M. & Aro, EM. 2013:  Phylogenetic viewpoints on regulation of light harvesting and electron transport in eukaryotic photosynthetic organisms. - PLANTA 237(2): 399-412.
Suorsa, M.; Järvi, S.; Grieco, M.; Nurmi, M.; Pietrzykowska*, M.; Rantala, M.; Kangasjärvi, S.; Paakkarinen, V.; Tikkanen, M.; Jansson*, S. & Aro, EM. 2012:  PROTON GRADIENT REGULATION5 is essential for proper acclimation of Arabidopsis Photosystem I to naturally and artificially fluctuating light conditions. - PLANT CELL 24(7): 2934-2948.
Tikkanen, M.;  Gollan, P.; Suorsa, M.; Kangasjärvi, S. &  Aro, EM. 2012:  STN7 operates in retrograde signaling through controlling redox balance in the electron transfer chain. - FRONTIERS IN PLANT PHYSIOLOGY 3(277): 1-11.   Free article
Grieco, M.; Tikkanen, M.; Paakkarinen, V.; Kangasjärvi, S. & Aro, EM. 2012:  Steady-state phosphorylation of light-harvesting complex II proteins preserves Photosystem I under fluctuating white light. - PLANT PHYSIOLOGY 160(4): 1896-1910.   Free Article
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
Kangasjärvi, S.; Neukermans*, J.; Li, S.; Aro, EM. & Noctor*, G. 2012: Photosynthesis, photorespiration, and light signalling in defence responses. - JOURNAL OF EXPERIMENTAL BOTANY  63(4): 1619-1636.
Trotta, A.; Konert, G.; Rahikainen, M.; Aro, EM. & Kangasjärvi, S. 2011:  Knock-down of protein phosphatase 2A subunit B'γ promotes phosphorylation of CALRETICULIN 1 in Arabidopsis thaliana. - PLANT SIGNALING AND BEHAVIOR 6(11):1665-1668.
Trotta, A.; Wrzaczek*, M.; Scharte*, J.; Tikkanen, M.; Konert, G.; Rahikainen, M.; Holmström, M.; Hiltunen, HM.; Rips*, S.; Sipari*, N.; Mulo, P.; Weis*, E.; von Schaewen*, A.; Aro, EM. & Kangasjarvi, S. 2011:  Regulatory subunit B'γ of protein phosphatase 2A prevents unnecessary defense reactions under low light in Arabidopsis thaliana. - PLANT PHYSIOLOGY 156(3):1464-1480   Free article
*Wrzaczek, M., *Brosche, M., *Salojärvi, J., Kangasjärvi, S., *Idänheimo, N., *Mersmann, S., *Robatzek, S., *Karpinski, S., *Karpinska, B., *Kangasjärvi, J. 2010:  Transcriptional regulation of the CRK/DUF26 group of Receptor-like protein kinases by ozone and plant hormones in Arabidopsis. - BMC PLANT BIOLOGY 10:95   Free article
Yin, L. Lundin, B. Bertrand, M. Nurmi, M., Solymosi, K., Kangasjärvi, S. Aro, E.-M., Schoefs, B.and Spetea, C. (2010) Role of Thylakoid ATP/ADP Carrier in Photoinhibition and Photoprotection of Photosystem II in Arabidopsis. PLANT PHYSIOLOGY 153(2): 666-677.   Free Article
Tikkanen, M., Grieco, M., Kangasjärvi, S. and Aro, E.-M. (2010): Thylakoid protein phosphorylation in higher plant chloroplasts optimises electron transfer under fluctuating light. PLANT PHYSIOLOGY 152(2): 723-735.   Free PMC Article
Broche, M., Overmyer, K., Wrzaczek, M., Kangasjärvi, J and Kangasjärvi, S. (2010) Stress signaling: reactive oxygen species. In: Bohnert, H., Govindjee, Pareek, A. and Sopory, S. (Eds.): Abiotic Stress Adaptation in Plants: Physiological, Molecular and Genomic Foundation (Springer, Dordrecht, The Netherlands), pp. 91-102. DOI: 10.1007/978-90-481-3112-9_5.
Rintamäki, E., Lepistö, A. and Kangasjärvi, S. (2009) Implication of chlorophyll biosynthesis on chloroplast-to-nucleus retrograde signaling. Plant Signaling & Behavior 4: 545-547.
Kangasjärvi, S., Nurmi, M., Tikkanen, M. and Aro, E.-M. (2009) Cell-specific mechanisms and systemic signalling as emerging themes in light acclimation of C3 plants. Plant Cell and Environment 32:1230-1240.
Lepistö A, Kangasjärvi S, Luomala EM, Brader G, Sipari N, Keranen M, Keinänen M, Rintamäki E (2009) Chloroplast NADPH Thioredoxin Reductase Interacts with Photoperiodic Development in Arabidopsis thaliana. Plant Physiology 149:1261-1276.
Tikkanen, M., Nurmi, M., Kangasjärvi, S. and Aro, E.-M. (2008) Core protein phosphorylation facilitates the repair of photodamaged photosystem II at high light. Biochimical and Biophysical Acta. 1777:1432-1437.
Lintala M, Allahverdiyeva Y, Kangasjärvi S, Lehtimäki N, Keränen M, Rintamäki E, Aro EM, Mulo P. (2009): Comparative analysis of leaf-type ferredoxin-NADP(+)-oxidoreductase isoforms in Arabidopsis thaliana. Plant J 57:1103-1115.
Overmyer, K., Kollist, H.,  Tuominen, H., Betz, C., Langebartels, C, Wingsle, G., Kangasjärvi, S., Brader, G., Mullineaux, P., and Kangasjärvi, J (2008) Complex phenotypic profiles leading to ozone sensitivity in Arabidopsis thaliana mutants. Plant Cell and Environment 31: 1237-1249.
Kangasjärvi, S, Lepistö, A, Hännikäinen, K., Luomala, E.-M., Aro, E.-M. and Rintamäki, E. (2008) Dissection of the role of chloroplast stromal and thylakoid-bound ascorbate peroxidases in plant stress responses. Biochemical Journal 412:275-285.