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Research Programmes

 

Functional Genomics and Proteomics of Plants

hejatko_logoRNDr. Jan Hejátko, Ph.D.
Research Group Leader

THEMATIC RESEARCH FOCUS

RESEARCH AREAS

  • Role of cytokinins in the vascular tissue and root apical meristem formation and development
  • Interaction of cytokinin and other hormones, particularly auxin
  • Interaction of cytokinins with light
  • Structural basis of multistep phosphorelay signaling in plants
  • Plant proteome and phosphoproteome response to cytokinins
  • Employing the knowledge of molecular mechanisms of multistep phosphorelay-based signalling in molecular breeding
  • Production of bioactive compounds in plant production systems

MAIN OBJECTIVES

Determination of molecular mechanisms governing hormonal regulations and their functions in plant development.

CONTENT OF RESEARCH

The research group is interested in the hormonal regulation of plant development and underlying molecular mechanisms with particular emphasis on the understanding of cytokinin signalling, action and interaction with other plant growth regulators.

Plant cells are well known for their tremendous developmental plasticity. Plant hormones, particularly auxins and cytokinins were found to be major regulators of intrinsic developmental programs associated with changes of differentiation status of plant cells and tissues. That allows de novo formation of entire plants from virtually all types of specialised plant tissues. Identification of basic molecular principles involved in the regulation of plant cell division and differentiation will provide developmental model useful in the comparative biology approaches and identification of corresponding regulatory and developmental events in animal and particularly human cell systems.

In the group of Functional Genomics and Proteomics of Plants, we are interested in the molecular mechanisms underlying the regulation of plant development by plant hormones cytokinins (CKs) and their interaction with other plant hormones, e.g. auxin. In our studies we employ comprehensive approaches including forward and reverse genetics, proteomics, protein biochemistry, protein structure analysis and bioinformatics to recognise the principles of complex molecular events involved in the cytokinin signal transduction and action.

We are particularly interested in study of following problems:

  1. Interaction of auxin and cytokinins in the processes of de novo organogenesis, regulation of root meristem patterning and vascular tissue development. We are interested in the identification of molecular targets acting downstream the CK signalling pathways and the role of gene regulatory networks constituting CKdependent developmental circuits.
  2. Elucidating molecular determinants of specifi city in multistep phosphorelay (MSP), with special emphasis on the role of MSP in CK signalling. Particularly we are interested in the structural analysis of intracellular receiver domains of sensory histidine kinases that, as we have found, specifically interact with downstream signaling His-containing phosphotransfer proteins, determining thus specificity in plant MSP pathways.
  3. Hormonal regulations of plant proteome, particularly the study of CK-dependent proteome changes with the aim of identifying novel regulatory targets of CK-mediated regulations of plant development and elucidating molecular mechanisms underlying interaction of CK with other plant growth regulators, e.g. ethylene.
  4. Development and application of novel approaches, e.g. immunomodulation (production of scFv fragments recognising both cytokinins and CK signalling proteins in vivo) to modulate CK-dependent regulation of plant development.

Extending our fundamental research and use of its results in applied science and development of novel strategies useful in e.g. molecular breeding or using of plant systems for biotherapeutics production.

KEY RESEARCH EQUIPMENT

PLANNED RESEARCH INFRASTRUCTURE

Technology Units

Molecular biology, genomics and proteomics of plants

CURRENT RESEARCH INFRASTRUCTURE

Equipment for cultivation of plants under tightly regulated conditions (fytotrons) and under defined light quality and quantity. Expertise and high-end instrumentation in advanced microscopy techniques that include high-end confocal microscope equipped with white laser, highly sensitive hybrid detectors and module for fluorescence life-time imaging (FLIM) and fluorescence correlation spectroscopy (FCS). Image analysis software allowing highly sensitive and specific fluorescence imaging in living cells via fluorescence intensity decay shape analysis microscopy (FIDSAM). High-throughput system for automated microscopy (Olympus “slide”) and horizontal confocal macroscope (modified Nikon AZ-C1 system), allowing detailed, real-time fluorescent protein localisation and dynamics in vivo.

MAIN PROJECTS

  • The role of cytokinins and auxin interactions in the regulation of root gravitropism in Arabidopsis thaliana (GAP501/11/1150), Czech Science Foundation, 2011-2013, J. Hejátko, Masaryk University.
  • Immunomodulation as a functional proteomics tool for cytokinin signaling study in Arabidopsis thaliana (GA521/09/1699), Czech Science Foundation, 2009-2012, L. Janda, Masaryk University, M. Faldyna, Veterinary Research Institute.
  • Identification of molecular components and the mechanism of polar targeting of PIN auxin transport proteins in Arabidopsis thaliana (IAA601630703), Academy of Sciences of the Czech Republic, 2007-2011, J. Friml, Masaryk University.
  • Structural basis for the specificity of signal transduction in plants: interaction network of histidine kinase receiver domains in Arabidopsis (GAP305/11/0756), Czech Science Foundation, 2011-2014, L. Žídek, Masaryk University.
  • Regulation of morphogenesis of plant cells and organs (LC06034), Ministry of Educaton, Youth and Sports, 2006-2011, E. Zažímalová, Institute of Experimental Botany AS CR, I. Kašík, Institute of Photonics and Electronics AS CR, Z. Opatrný, Charles University in Prague, J. Hejátko, Masaryk University, Z. Novotná, Chemical–Technology University in Prague, B. Brzobohatý, Mendel University in Brno.

SELECTED PUBLICATIONS

  • PEKAROVA, B., KLUMPLER, T., TRISKOVA, O., HORAK, J., JANSEN, S., DOPITOVA, R., BORKOVCOVA, P., PAPOUSKOVA, V., NEJEDLA, E., SKLENAR, V., MAREK, J., ZIDEK, L., HEJATKO, J., JANDA, L. Dynamic structure and binding specificity of the receiver domain of sensor histidine kinase CKI1 from Arabidopsis thaliana. Plant Journal. 2011, 67, p. 827-839.
  • HORAK, J., JANDA, L., PEKAROVA, B., HEJATKO, J. Molecular Determinants of the Signalling Specificity via Phosphorelay Pathways in Arabidopsis. Current Protein & Peptide Science. 2010, 12, p. 126-136.
  • HEJATKO, J., RYU, H., KIM, G., T., DOBESOVA, R., CHOI, S., CHOI, S., M., SOUCEK, P., HORAK, J., PEKAROVA, B., PALME, K., BRZOBOHATY, B., HWANG, I. The histidine kinases CYTOKININ-INDEPENDENT1 and ARABIDOPSIS HISTIDINE KINASE2 and 3 regulate vascular tissue development in Arabidopsis shoots. Plant Cell. 2009, 21(7), p.2008-2021.
  • PERNISOVA, M., KLIMA, P., HORAK, J., VALKOVA, M., MALBECK, J., SOUCEK, P., REICHMAN, P., HOYEROVA, K.,DUBOVA, J., FRIML, J., ZAZIMALOVA, E., HEJATKO, J. Cytokinins modulate auxin-induced organogenesis in plants via regulation of the auxin efflux. Proceedings of the National Academy of Sciences of the USA. 2009,106, p. 3609-3614.
  • KUDEROVA, A., URBANKOVA, I., VALKOVA, M., MALBECK, J., BRZOBOHATY, B., NEMETHOVA, D., HEJATKO, J. Effects of conditional IPT -dependent cytokinin overproduction on root architecture of Arabidopsis seed lings. Plant and Cell Physiology. 2008, 49, p. 570-582.
 

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