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Research areas
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Role of cytokinins in the vascular tissue and root apical meristem formation and development
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Interaction of cytokinin and other hormones, particularly auxin
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Interaction of cytokinins with light
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Structural basis of multistep phosphorelay signaling in plants
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Plant proteome and phosphoproteome response to cytokinins
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Employing the knowledge of molecular mechanisms of multistep phosphorelay-based signalling in molecular breeding
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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:
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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.
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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.
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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.
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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.
1. DIRIGENT Genes in the Control of Plant Development
Supervisor: doc. RNDr. Jan Hejátko, Ph.D.
Annotation:
In our lab we are interested in the study of plant hormonal signaling pathways, particularly cytokinins (CKs) in the development of model plant Arabidopsis thaliana (1-4). CK signaling is mediated via what is called multistep phosphorelay signaling (MSP). Recently we have found that CKs control xylem differentiation via regulation of the composition of the cell wall and its biomechanical properties (Didi et al., unpublished). Our bioinformatics as well as experimental evidence suggest that there are more direct targets of CK signaling pathway with a potential role in the control of the cell wall properties. Among these are members of the almost completely unexplored Arabidopsis thaliana DIRIGENT (AtDIR) gene family. Based on our preliminary results it seems that AtDIRs could have an important role in the plant response to both biotic and abiotic stress as well as in the control of plant organogenesis. The aim of the project is to analyze the role of AtDIR13 and AtDIR14 in the Arabidopsis development. The work will include using up-to-date genetics, molecular biology and advanced imaging approaches including the recently introduced Brillouin imaging developed for the non-invasive measurement of biomechanical cell wall properties (5). The project promises to uncover novel mechanisms underlying hormonal control of plant development of fundamental importance. We offer: Experimental work on own project with the possibility of publication in distinguished international journals, nice lab staff, world-class lab equipment, attractive environment of novel university campus, help with both intellectual and practical problems, competitive salary corresponding to the work efficiency, collaboration with abroad lab. The position will be available from January 1 2018. Contact and further info: +420 5 4949 4165, hejatko@sci.muni.cz
References:
1. Dobisova, T., et al. (2017). Plant Physiol 174, 387-404.
2. Paniagua, C., et al. (2017). J Exp Bot.
3. Pernisova, M., et al. (2016). New Phytol 212, 497-509.
4. Zd'arska, M., et al. (2013). Plant Physiology 161, 918-930.
5. Elsayad, K., et al. (2016). Sci Signal 9, rs5.
Keywords: cytokinins, CKs, multistep phosphorelay signaling, MSP, AtDIR, Brillouin imaging, plant hormonal signaling pathways, mdel plant Arabidopsis thaliana
2. Genetic variability in multistep phoshorelay signaling in plants
Supervisor: doc. RNDr. Jan Hejátko, Ph.D.
Annotation
In our lab we are interested in the study of plant hormonal signaling pathways, particularly cytokinins in the development of model plant Arabidopsis thaliana (1-3). Cytokinin signaling is mediated via what is called multistep phosphorelay signaling (MSP). Cytokinins were described as important regulators of biotic and abiotic stresses, making members of the MSP signaling pathway attractive targets in breeding programs aimed to the improvement of crop adaptation responses. Previously we have identified sensor histidine kinases working as cytokinin receptors in oil-seed rape (4). However, our knowledge on the mechanism of action of MSP signaling in crops is very limited. In frame of the project, we will study the genetic variability in individual members of the MSP signaling pathway in Arabidopsis and oil-seed rape. The role of identified variants in the cytokinin responsiveness will be tested using transgenic plants carrying the transcriptional MSP reporters as well as transient expression in plant protoplasts. Molecular mechanisms of identified polymorphisms in cytokinin responsiveness will be studied by experimental as well as structural modeling approaches. The work will include using up-to-date genetics, molecular biology and advanced imaging approaches. The project will be solved in a tight collaboration with Photon Systems Instruments company, employing their cutting-edge plant phenotyping platform. Results with impact on both fundamental research of MSP signaling as well as high application potential are expected. We offer: Experimental work on own project with the possibility of publication in distinguished international journals, nice lab staff, world-class lab equipment, attractive environment of novel university campus, help with both intellectual and practical problems, competitive salary corresponding to the work efficiency, collaboration with abroad lab. The position will be available from Aug/Sep 2018. We expect: Highly motivated candidates with ambition of reaching top-ranked results.
References:
1. Dobisova, T., et al. (2017). Plant Physiol 174, 387-404.
2. Pernisova, M., et al. (2016). New Phytol 212, 497-509.
3. Pernisova, M., et al. (2009). Proc Natl Acad Sci U S A 106, 3609-3614.
4. Kuderova, A., et al. (2015). Journal of Experimental Botany 66, 339-353.
Keywords: cytokinins, multistep phosphorelay signaling, MSP, cytokinin receptors, plant phenotyping, biotic and abiotic stresses
3. Structural and functional analysis of cytokinin-regulated DIRIGENT proteins from Arabidopsis thaliana
Supervisor: Ing. Blanka Pekárová, Ph.D.
Consultant: doc. RNDr. Jan Hejátko, Ph.D.
Annotation
Our Research Group Functional Genomics and Proteomics of Plants has been investigating plant hormonal signaling pathways, particularly cytokinins and ethylene in the development of model plant Arabidopsis thaliana (1-4) for a long time. Recently, we have turned our attention to understand the molecular mechanisms mediating cytokinin regulations of the cell wall composition and thus its biomechanical properties. We found that two out of 26 Arabidopsis DIRIGENT proteins (AtDIR13 and AtDIR14) are up-regulated by cytokinins in the Arabidopsis roots and they also seem to be direct targets of cytokinin signaling (2). AtDIR6 is the only member of the family with known structure (5). DIRIGENT proteins are glycoproteins mediating biosynthesis of lignan and lignin, phenolic compounds important in plant development. Some DIRIGENT proteins were shown to be involved in the biotic and abiotic stress responses. Additionally, lignin that represents approx. 15-30% dry weight of lignocellulose has potential as a renewable source of high-value aromatic chemicals. Lignans can be used as drugs in conventional medicine. The aim of this work is to clone, express, purify and crystallize AtDIR13/14 proteins and use them in the series of in vitro enzymatic assays in order to identify their substrate specificity and putative role in the catalysis of lignin and/or lignan formation. We expect: Highly motivated candidates with ambition of reaching top-ranked results. We offer: Experimental work on own project with the possibility of publication in distinguished international journals, nice lab staff, world-class lab equipment, attractive environment of novel university campus, help with both intellectual and practical problems, competitive salary corresponding to the work efficiency. The position will be available from January 2018. Contact and further info: +420 5 4949 3029, pekarova@sci.muni.cz, hejatko@sci.muni.cz
References:
1. Dobisova, T., et al. (2017). Plant Physiol. 174, 387-404.
2. Paniagua, C., et al. (2017). J Exp Bot. 68, 3287-3301.
3. Pernisova, M., et al. (2016). New Phytol. 212, 497-509.
4. Zdarska, M., et al. (2013). Plant Physiol. 161, 918-930.
5. Gasper, R., et al. (2016). Plant Physiol. 172, 2165-2175.
Keywords: cytokinin regulations, Arabidopsis DIRIGENT proteins,AtDIR13, AtDIR14, plant model Arabidopsis thaliana, hormonal signaling pathways
4.The role of cytokinin-inducible EXPANSINs in the control of cell wall properties and development in Arabidopsis
Supervisor: Mgr. Markéta Šámalová, Ph.D.
Consultant: doc. RNDr. Jan Hejátko, Ph.D.
Annotation
In our lab we are interested in the study of plant hormonal signaling pathways, particularly cytokinins (CKs) in the development of model plant Arabidopsis thaliana (1-4). Our recent preliminary data suggest an important role for CK-regulated genes, namely EXPANSINs, in the control of cell wall (CW) properties. Besides CW critical developmental importance in plants, CW-based biomaterials are exploited in diverse human activities and have high application potential as a source of sustainable and renewable energy for the future. The aim of the project is to investigate a novel role for CKs in the regulation of CW composition and structure during CK-controlled cell differentiation. We hypothesize that CKs control cell differentiation via regulation of biomechanical properties of the CW. As an important part of the project we will employ the CRISPR-Cas9 gene-editing technology and brand-new optical method, Brillouin imaging, developed for the non-invasive measurement of biomechanical CW properties (5). We expect: Highly motivated, ambitious candidates with interest in molecular biology and plants. We offer: Experimental work on own project with the possibility of publication in top-ranked international journals, friendly lab staff, world-class equipment, attractive environment of novel university campus, help with both intellectual and practical problems, competitive salary corresponding to the work efficiency. The position is available from January 2018. Contact and further info: +420 5 4949 8476, marketa.samalova@ceitec.muni.cz hejatko@sci.muni.cz
References:
1. Dobisova, T., et al. (2017). Plant Physiol 174, 387-404.
2. Paniagua, C., et al. (2017). J Exp Bot.
3. Pernisova, M., et al. (2016). New Phytol 212, 497-509.
4. Zd'arska, M., et al. (2013). Plant Physiology 161, 918-930.
5. Elsayad, K., et al. (2016). Sci Signal 9, rs5.
Keywords: CK-regulated genes, EXPANSINs, cell wall properties control, CRISPR-Cas9 gene-editing, Brillouin imaging
