Katharina Pawlowski

Katharina Pawlowski


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Works at Department of Ecology, Environment and Plant Sciences
Telephone 08-16 37 72
Visiting address Svante Arrhenius väg 20 A
Room N424
Postal address Institutionen för ekologi miljö och botanik 106 91 Stockholm

About me


  • 1980-1982 University of Heidelberg (Germany), study of Biology; Pre-Diploma (subjects: Zoology, Botany, Genetics)
  • 1982-1986 University of Cologne (Germany), study of Biology; Diploma (subjects: Genetics, Botany, Biochemistry)
  • 1989 PhD in Biology at the University of Cologne, research performed at the Max Planck Institute for Plant Breeding Research, Cologne, in the Department of Jeff Schell, in the group of Frans de Bruijn, Title of PhD thesis: Studien zur Häm-Biosynthese und zur Regulation des Stickstoffhaushalts von Azorhizobium caulinodans ORS571 im freilebenden Zustand und in Symbiose mit Sesbania rostrata.
  • 2003 Habilitation (qualification for professorship), University of Göttingen

Academic appointments:

  • 1990 - 1991 Researcher, Max Planck Institute for Plant Breeding Research, Cologne
  • 1991 - 1997 Researcher, Agricultural University of Wageningen, The Netherlands
  • 1997 - 2005 Assistant professor at the Department of Plant Biochemistry, University of Göttingen, Germany
  • 2005 - 2007 Lecturer at the Department of Botany, Stockholm University

Current position:

Since 2007 Professor in plant-microbe interactions at Stockholm University, Department of Botany (now: Department of Ecology, Environment and Plant Sciences)




Nitrogen-fixing root nodule symbioses


Nitrogen is the element that most often limits plant growth. Only prokaryotes that can form the nitrogenase enzyme complex can reduce air dinitrogen to ammonia and thereby bring it from the atmosphere into the biosphere. Plants that can enter a root nodule symbiosis with nitrogen-fixing soil bacteria are independent of soil nitrogen, i.e. fertilizer. In root nodules, the microsymbionts are hosted within plant cells, fix dinitrogen and deliver the products of nitrogen fixation to the host plant, while the host plant supplies them with carbon sources. Only plants belonging to a particular group, the so-called Fabid clade (but not all of them), are able to establish a root nodule symbiosis. Two groups of microsymbionts are involved in these symbioses – rhizobia with legumes and with Parasponia sp. from the Cannabaceae family, and Frankia strains with actinorhizal plants. Actinorhizal plants - mostly trees or woody shrubs - belong to eight different families from three different orders (Fagales, Rosales and Cucurbitales; look here for details).


Evolution of root nodule symbioses

The question arises which common feature of these plants represents the precondition that allowed the evolution of a root nodule symbiosis. Therefore, we compare root nodule symbioses from different branches of the Fabid clade in order to identify the common vs. family-specific features. The wide phylogenetic range of actinorhizal plant means that there is significant diversity among symbioses involving host plants from different families (see here). We are working on different plant species:



Medicago truncatula - model legume, indeterminate nodules, intracellular infection by Sinorhizobium meliloti

Lotus japonicus - model legume, determinate nodules, intracellular infection by Mesorhizobium loti


Actinorhizal plants:

Casuarina glauca (swamp oak) - Australian tree, intracellular infection by Frankia cluster I

Datisca glomerata (Durango root) - Northwest American suffruticose plant, pathway of infection by Frankia cluster II under examination

Ceanothus thyrsiflorus – Northwest American shrub, intercellular infection by Frankia cluster II


On the microbsymbiont side, in contrast with rhizobia, Frankia strains are monophyletic. Phylogenetically, there are four Frankia clusters, three of which representing facultative symbionts while cluster IV contains only non-symbiotic strains. Genome sizes differ strongly between strains from different clusters (cluster I genomes are ca. 7.5 MB in size except for the subgroup that nodulates Casuarinaceae which with 5.3 – 5.7 MB shows stronger genome reduction, cluster II genomes (5.3-5.6 MB) also show strong genome reduction, while clusters III (9-10 MB) and IV (ca. 10 MB) have the largest genome). Host range is correlated with phylogeny – e.g., members of cluster I nodulate actinorhizal Fagales (with the exception of Gymnostoma sp. (Casuarinaceae) and Myrica sp. (Myricaceae), members of cluster II nodule actinorhizal Cucurbitales and from the Rosales the actinorhizal Rosaceae and Ceanothus sp. (Rhamnaceae). Members of cluster III nodulate actinorhizal members of two Rosales families (Elaeagnaceae and Rhamnaceae with the exception of Ceanothus sp.) and the outlier genera of the actinorhizal Fagales, Gymnostoma sp. and Myrica sp. However, as a rule a member of a particular cluster cannot nodulate all host plants of said cluster.

            Phylogenetically, cluster II is basal to all other Frankia clusters (see here). So far, only one member of this cluster could be cultured, and this one, in contrast with all other known Frankia strains, is alkaliphile (see here). We are particularly interested in the evolution of cluster II and its host plants.


Projects (people from SU underlined):

  • Comparison of Frankia cluster II genomes from different areas (Fede Berckx, Hsiao-Han Lin, Cyndi Mae Bandong, Than Van Nguyen, Daniel Wibberg, Jörn Kalinowski)
  • Control of the microsymbiont by the plant in nodules of Datisca glomerata: characterization of nodule-specific cysteine-rich peptides (Irina Demina, Marco Salgado)
  • What is the carbon source provided by Datisca glomerata to its microsymbiont? (Marco Salgado, Irina Demina, Fede Berckx, Sabine Zimmermann)
  • Mechanism of stable internal accommodation of Frankia in actinorhizal nodules of Casuarina glauca and Datisca glomerata (Behnoosh Rashidi, Kirill Demchenko)
  • Conservation of transcription factors involved in nodule development: activity of nodule-specific promoters in heterologous systems (Behnoosh Rashidi, Sara Mehrabi, Patricia Santos, Beth Mullin)
  • Differentiation of infected cells in Datisca glomerata: transcriptome analysis using laser capture microdissection (Irina Demina, Marco Salgado, Nicole Gaude, Franziska Krajinski, Max Griesmann, Christoph Ziegenhain, Wolfgang Enard)
  • Comparison of nodule development and differentiation in two host plants of cluster II Frankia, Datisca glomerata and Ceanothus thyrsiflorus (Thanh Van Nguyen, Marco Salgado, Fede Berckx, Rolf Hilker, Daniel Wibberg, Jörn Kalinowski, Kai Battenberg, Alison Berry)
  • Effects of salt stress on actinorhizal plants with different nodule oxygen protection mechanisms (Stefano Papazian, Benedicte Albrectsen, Ana Ribeiro, Małgorzata Plaszczyca, Thanh Van Nguyen)
  • Metabolomics of actinorhizal nodules (Tomas Persson, Thanh Van Nguyen, Fede Berckx, Stefano Papazian, Benedicte Albrectsen, Alison Berry, Nicole Alloisio, Philippe Normand)
  • Auxin and Datisca glomerata nodules (Irina Demina, Pooja Jha Maity, Anurupa Nagchowdhury, Marco Salgado, Ulrike Mathesius)


Group members (current):

  • Fede Berckx (PhD student)
  • Marco Salgado (PhD student)


Former group members:

  • Anna Maria Zdyb (PhD) (now: Institute of Genetics, Technical University Dresden, Zellescher Weg 20b, 01062 Dresden, Germany)
  • Małgorzata Płaszczyca (PhD) (now: Rybnik, Poland)
  • Patricia Santos (PostDoc) (now: Department of Biochemistry and Molecular Biology, University of Nevada, Reno 89557, NV, USA)
  • Behnoosh Rashidi (PhD) (now: Copenhagen, Denmark)
  • Sara Mehrabi (MSc) (now: Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm, Sweden)
  • Tomas Persson (PhD) (now: Department for Mathematics and Science Education, Stockholm University)
  • Stefano Papazian (MSc) (now: Department of Plant Physiology, UPSC, Umeå University, 901 87 Umeå, Sweden)
  • Irina V. Demina (PhD) (now: Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK)
  • Anurupa Nagchowdhury (MSc) (now: Karolinska Institutet, Stockholm, Sweden)
  • Pooja Jha Maity (PostDoc) (now: Department of Botany, University of Delhi, Delhi 110 007, India)
  • Xiaoyun Gong (MSc) (now: Genetics, LMU Munich, Biocenter, Großhaderner Str. 4, 82152 Martinsried, Germany)
  • Thanh Van Nguyen (PhD) (now: Department of Organismal Biology, Uppsala University, 756 51 Uppsala, Sweden)


Funding (currently):



External collaborations:

  • Kai Battenberg and Alison M. Berry (Department of Plant Sciences, University of California, Davis 95616, CA, USA)
  • Martin Parniske, Benjamin Billault-Penneteau, Xiaoyun Gong and Max Griesmann (Genetics, LMU Munich, Biocenter, Großhaderner Str. 4, 82152 Martinsried, Germany)
  • Kirill Demchenko (Laboratory of Plant Anatomy & Morphology, V.L. Komarov Botanical Institute, Russian Academy of Sciences, 2 Prof. Popov Street, St.-Petersburg 197376, St.-Petersburg, Russia)
  • Olga Voitsekhovskaja (Department of Plant Physiologial Ecology, V.L. Komarov Botanical Institute, Russian Academy of Sciences, 2 Prof. Popov Street, 197376 St. Petersburg, Russia)
  • Daniel Wibberg and Jörn Kalinowski (CeBiTec, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany)
  • Rolf Hilker (Department of Bioinformatics and Systems Biology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany)
  • Pooja Jha Maity (Department of Botany, University of Delhi, Delhi 110 007, India)
  • Tinting Xiao and Ton Bisseling (Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands)
  • Lidija Berke (Biosystematics, Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands)
  • Patricia Santos and Dylan Kosma (Department of Biochemistry and Molecular Biology, University of Nevada, Reno 89557, NV, USA)
  • Stefano Papazian and Benedicte Albrectsen (Department of Plant Physiology, UPSC, Umeå University, 901 87 Umeå, Sweden)
  • Petar Pujic, Nicole Alloisio and Philippe Normand (Ecologie Microbienne, Universite Lyon 1, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France)
  • Sabine Zimmermann (Biochimie et Physiologie Moleéculaire des Plantes, UMR 5004 CNRS/INRA/SupAgro/UM2, Campus INRA/SupAgro, 2 Place Viala, 34060 Montpellier Cedex 2, France)
  • Ana Ribeiro (ECO-BIO/IICT, Quinta do Marquês, 2784-505 Oeiras, Portugal)
  • Ulrike Mathesius (Division of Plant Science, Research School of Biology, Australian National University, Canberra ACT 2601, Australia)
  • Didier Bogusz and Claudine Franche (IRD Montpellier, France)
  • Beth Mullin (Department of Botany, University of Tennessee, Knoxville, TN 37996-1100, USA)
  • Franziska Krajinski (Institute of Biology, Applied and General Botany Lab, Leipzig University, Johannisallee 21-23, 04103 Leipzig, Germany)
  • Christoph Ziegenhain and Wolfgang Enard (Anthropology and Human Genetics, Department Biology II, Faculty of Biology, Ludwig-Maximilians University Munich, Großhaderner Straße 2, 82152 Martinsried, Germany)
  • Marcel Bucher (Botanical Institute, Cologne Biocenter, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany)


A selection from Stockholm University publication database
  • 2015. Tomas Persson (et al.). PLoS ONE 10 (5)

    Frankia strains are nitrogen-fixing soil actinobacteria that can form root symbioses with actinorhizal plants. Phylogenetically, symbiotic frankiae can be divided into three clusters, and this division also corresponds to host specificity groups. The strains of cluster II which form symbioses with actinorhizal Rosales and Cucurbitales, thus displaying a broad host range, show suprisingly low genetic diversity and to date can not be cultured. The genome of the first representative of this cluster, Candidatus Frankia datiscae Dg1 (Dg1), a microsymbiont of Datisca glomerata, was recently sequenced. A phylogenetic analysis of 50 different housekeeping genes of Dg1 and three published Frankia genomes showed that cluster II is basal among the symbiotic Frankia clusters. Detailed analysis showed that nodules of Datisca glomerata, independent of the origin of the inoculum, contain several closely related cluster II Frankia operational taxonomic units. Actinorhizal plants and legumes both belong to the nitrogen-fixing plant clade, and bacterial signaling in both groups involves the common symbiotic pathway also used by arbuscular mycorrhizal fungi. However, so far, no molecules resembling rhizobial Nod factors could be isolated from Frankia cultures. Alone among Frankia genomes available to date, the genome of Dg1 contains the canonical nod genes nodA, nodB and nodC known from rhizobia, and these genes are arranged in two operons which are expressed in Datisca glomerata nodules. Furthermore, Frankia Dg1 nodC was able to partially complement a Rhizobium leguminosarum A34 nodC::Tn5 mutant. Phylogenetic analysis showed that Dg1 Nod proteins are positioned at the root of both alpha- and beta-rhizobial NodABC proteins. NodA-like acyl transferases were found across the phylum Actinobacteria, but among Proteobacteria only in nodulators. Taken together, our evidence indicates an Actinobacterial origin of rhizobial Nod factors.

  • 2007. Anke Sirrenberg (et al.). Physiologia Plantarum 131, 581–589

    Piriformospora indica has been shown to improve the growth of many plant species including Arabidopsis thaliana, but the mechanism by which this is achieved is still unclear. Arabidopsis root colonization by P. indica was examined in sterile culture on the medium of Murashige and Skoog. P. indica formed intracellular structures in Arabidopsis root epidermal cells and caused changes in root growth, leading to stunted and highly branched root systems. This effect was because of a diffusible factor and could be mimicked by IAA. In addition, P. indica was shown to produce IAA in liquid culture. We suggest that auxin production affecting root growth is responsible for, or at least contributes to, the beneficial effect of P. indica on its host plants.

  • 2012. Katharina Pawlowski, Kirill N. Demchenko. Protoplasma 249 (4), 967-979

    Filamentous aerobic soil actinobacteria of the genus Frankia can induce the formation of nitrogen-fixing nodules on the roots of a diverse group of plants from eight dicotyledonous families, collectively called actinorhizal plants. Within nodules, Frankia can fix nitrogen while being hosted inside plant cells. Like in legume/rhizobia symbioses, bacteria can enter the plant root either intracellularly through an infection thread formed in a curled root hair, or intercellularly without root hair involvement, and the entry mechanism is determined by the host plant species. Nodule primordium formation is induced in the root pericycle as for lateral root primordia. Mature actinorhizal nodules are coralloid structures consisting of multiple lobes, each of which represents a modified lateral root without a root cap, a superficial periderm and with infected cells in the expanded cortex. In this review, an overview of nodule induction mechanisms and nodule structure is presented including comparisons with the corresponding mechanisms in legume symbioses.

  • 2011. Katharina Pawlowski (et al.). New Phytologist 189 (2), 568-579

    • Jasmonic acid (JA) is a plant signalling compound that has been implicated in theregulation of mutualistic symbioses. In order to understand the spatial distributionof JA biosynthetic capacity in nodules of two actinorhizal species, Casaurina glauca and Datisca glomerata, and one legume, Medicago truncatula, we determined thelocalization of allene oxide cyclase (AOC) which catalyses a committed step inJA biosynthesis. In all nodule types analysed, AOC was detected exclusively inuninfected cells.

    • The levels of JA were compared in the roots and nodules of the three plantspecies. The nodules and noninoculated roots of the two actinorhizal species, andthe root systems of M. truncatula, noninoculated or nodulated with wild-type Sinorhizobium meliloti or with mutants unable to fix nitrogen, did not showsignificant differences in JA levels. However, JA levels in all plant organs examined increased significantly on mechanical disturbance.

    • To study whether JA played a regulatory role in the nodules of M. truncatula, composite plants containing roots expressing an MtAOC1-sense or MtAOC1-RNAi construct were inoculated with S. meliloti. Neither an increase nor reductionin AOC levels resulted in altered nodule formation.

    • These data suggest that jasmonates are not involved in the development andfunction of root nodules.

Show all publications by Katharina Pawlowski at Stockholm University

Last updated: September 19, 2019

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