Group of auxin transport

Head: Jan Petrášek

We focus on the molecular mechanism of polar auxin transport and on the ways of its regulation.

Polar auxin transport (PAT) is the process, in which plant hormone auxin is transported in cell-to-cell manner. The word “polar” refers to the fact that this type of transport is directional, either within the region of particular tissue or among tissues. Directionality of PAT is maintained by the interplay of diffusion and carrier-mediated transport of auxin across plasma membrane. The reason why PAT plays very important role in plant development is that it helps to establish auxin concentration gradients that subsequently regulate gene expression and also many other post-translational processes. Our recent research is focused on the understanding of how plasma membrane-located and endomembrane auxin transporters contribute to the overall auxin homeostasis within the cells. Read more…

Group of metabolism and physiological function of cytokinins

Head: Václav Motyka

We are engaged in the research of cytokinins, i.e. plant hormones that regulate cell division and differentiation and thus efficiently control plant growth and development.

Cytokinins are naturally occurring phytohormones that act in concert with auxins to regulate cell division and differentiation and thus efficiently control plant growth and development. Transient enhancement of auxin in relation to cytokinin levels induces root formation while the opposite shift results in shoot formation. Re-establishment of the two hormone quantitative ratios (hormonal homeostasis) is essential for further development of induced events.

Endogenous levels of bioactive cytokinins and their mode of action in plants are regulated at different levels and by various mechanisms concerning biosynthesis, metabolic conversions, inactivation and degradation as well as signalling pathways and transport. Read more…

Group of the role of phytohormones in the interaction with environment

Head: Radka Vaňková

We focus on the elucidation of plant defence mechanisms, with the aim to contribute to the development of effective strategies to enhance stress tolerance of plants.

Plants have evolved complex systems of defence against, and adaption to, the variable and often potentially damaging environmental conditions to which they are exposed during their growth and development. Due to their sessile character, plants need to respond very dynamically to various abiotic (drought, extreme temperatures, high light intensity) as well as biotic stresses (pest and pathogen attacks).

Development of plants as well as their interactions with environment are regulated by plant hormones. Each phytohormone affects a range of physiological processes and vice versa each process is regulated (in positive or negative mode) by several hormones. Hormones mediate both fast responses (e.g. stomata closure during water deficit) and long-term adaptations, associated with modulation of growth and development. Positive regulators of cell division and growth are predominantly cytokinins and auxins. Negative growth regulator, which plays a decisive role during the seed development as well as in the response to abiotic stresses (especially to those associated with water deficit), is abscisic acid. The aim of our work is to characterize the role of individual plant hormones (especially of cytokinins, auxin and abscisic acid) in the response to abiotic and biotic stresses, to evaluate their intensive cross-talk and to elucidate the underlying mechanisms as well as to elucidate cytokinin roles in plant development. Read more…

Group of mathematical modelling

Head: Klára Hoyerová

Our group uses mathematical modelling approach to unravel regulatory mechanisms of polar auxin flow in plants.

Nowadays, mathematical modelling is used as a tool for studying auxin transport more and more often. Present models are sometimes excessively simplified and/or do not reflect the structure of the real system properly. We have focused on construction of a detailed model of auxin transport mechanisms in plant cells using experimental data to analyse particular transport mechanism separately (an analytical-synthetic approach). These data include measurements of accumulation kinetics of radiolabeled auxins in cell suspensions and HPLC analysis of radiolabeled auxin metabolism, which has both provided valuable information about auxin transport properties at cellular level. Read more…

Analytical unit

Head: Petr Dobrev

The analytical unit of our laboratory works on improving of existing and developing of new analytical procedures for purification, quantitation and metabolic profiling of plant hormones and some other bioactive substances of plant origin. Read more…